Duke Energy (DUK) 10-K 20 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-32853
Entity Registrant Name	DUKE ENERGY CORPORATION
Entity Tax Identification Number	20-2777218
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	550 South Tryon Street
Entity Address, City or Town	Charlotte
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	28202-1803
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 64,230,558,771
Entity Common Stock, Shares Outstanding		733,321,965
Documents Incorporated by Reference	Portions of the Duke Energy definitive proxy statement for the 2020 Annual Meeting of the Shareholders or an amendment to this Annual Report are incorporated by reference into PART III, Items 10, 11 and 13 hereof. This combined Form 10-K is filed separately by eight registrants: Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio, Duke Energy Indiana and Piedmont (collectively the Duke Energy Registrants). Information contained herein relating to any individual registrant is filed by such registrant solely on its own behalf. Each registrant makes no representation as to information relating exclusively to the other registrants.
Entity Central Index Key	0001326160
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	DUK
Security Exchange Name	NYSE
Junior Subordinated Debentures 5.125% Coupon Due January 2073
Document Information [Line Items]
Title of 12(b) Security	5.125% Junior Subordinated Debentures
Trading Symbol	DUKH
Security Exchange Name	NYSE
Junior Subordinated Debentures 5.625% Coupon Due September 2078
Document Information [Line Items]
Title of 12(b) Security	5.625% Junior Subordinated Debentures
Trading Symbol	DUKB
Security Exchange Name	NYSE
Depositary Share
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares
Trading Symbol	DUK PR A
Security Exchange Name	NYSE
Duke Energy Carolinas
Document Information [Line Items]
Entity File Number	1-4928
Entity Registrant Name	DUKE ENERGY CAROLINAS, LLC
Entity Tax Identification Number	56-0205520
Entity Incorporation, State or Country Code	NC
Entity Address, Address Line One	526 South Church Street
Entity Address, City or Town	Charlotte
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	28202-1803
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0000030371
Current Fiscal Year End Date	--12-31
Progress Energy
Document Information [Line Items]
Entity File Number	1-15929
Entity Registrant Name	PROGRESS ENERGY, INC.
Entity Tax Identification Number	56-2155481
Entity Incorporation, State or Country Code	NC
Entity Address, Address Line One	410 South Wilmington Street
Entity Address, City or Town	Raleigh
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27601-1748
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0001094093
Current Fiscal Year End Date	--12-31
Duke Energy Progress
Document Information [Line Items]
Entity File Number	1-3382
Entity Registrant Name	DUKE ENERGY PROGRESS, LLC
Entity Tax Identification Number	56-0165465
Entity Incorporation, State or Country Code	NC
Entity Address, Address Line One	410 South Wilmington Street
Entity Address, City or Town	Raleigh
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27601-1748
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0000017797
Current Fiscal Year End Date	--12-31
Duke Energy Florida
Document Information [Line Items]
Entity File Number	1-3274
Entity Registrant Name	DUKE ENERGY FLORIDA, LLC
Entity Tax Identification Number	59-0247770
Entity Incorporation, State or Country Code	FL
Entity Address, Address Line One	299 First Avenue North
Entity Address, City or Town	St. Petersburg
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	33701
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0000037637
Current Fiscal Year End Date	--12-31
Duke Energy Ohio
Document Information [Line Items]
Entity File Number	1-1232
Entity Registrant Name	DUKE ENERGY OHIO, INC.
Entity Tax Identification Number	31-0240030
Entity Incorporation, State or Country Code	OH
Entity Address, Address Line One	139 East Fourth Street
Entity Address, City or Town	Cincinnati
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45202
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0000020290
Current Fiscal Year End Date	--12-31
Duke Energy Indiana
Document Information [Line Items]
Entity File Number	1-3543
Entity Registrant Name	DUKE ENERGY INDIANA, LLC
Entity Tax Identification Number	35-0594457
Entity Incorporation, State or Country Code	IN
Entity Address, Address Line One	1000 East Main Street
Entity Address, City or Town	Plainfield
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46168
City Area Code	704
Local Phone Number	382-3853
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0000081020
Current Fiscal Year End Date	--12-31
Piedmont
Document Information [Line Items]
Entity File Number	1-6196
Entity Registrant Name	PIEDMONT NATURAL GAS COMPANY, INC.
Entity Tax Identification Number	56-0556998
Entity Incorporation, State or Country Code	NC
Entity Address, Address Line One	4720 Piedmont Row Drive
Entity Address, City or Town	Charlotte
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	28210
City Area Code	704
Local Phone Number	364-3120
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0000078460
Current Fiscal Year End Date	--12-31

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenues
Regulated electric		$ 22,615	$ 22,097	$ 21,177
Regulated natural gas		1,759	1,773	1,734
Nonregulated electric and other		705	651	654
Total operating revenues		25,079	24,521	23,565
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		6,826	6,831	6,350
Operation, maintenance and other		6,066	6,463	5,944
Depreciation and amortization		4,548	4,074	3,527
Property and other taxes		1,307	1,280	1,233
Impairment charges		(8)	402	282
Total operating expenses		19,366	19,747	17,968
(Losses) Gains on Sales of Other Assets and Other, net		(4)	(89)	28
Operating Income		5,709	4,685	5,625
Other Income and Expenses
Equity in earnings of unconsolidated affiliates		162	83	119
Other income and expenses, net		430	399	508
Total other income and expenses		592	482	627
Interest Expense		2,204	2,094	1,986
Income (Loss) from Continuing Operations before Income Taxes		4,097	3,073	4,266
Income Tax Expense From Continuing Operations		519	448	1,196
Income From Continuing Operations		3,578	2,625	3,070
(Loss) Income From Discontinued Operations, net of tax		(7)	19	(6)
Net Income		3,571	2,644	3,064
Less: Net (Loss) Income Attributable to Noncontrolling Interests		(177)	(22)	5
Net Income Attributable to Parent		3,748	2,666	3,059
Less: Preferred Dividends		41
Net Income Available to Common Stockholders		3,707	2,666	3,059
Other Comprehensive (Loss) Income, net of tax(a)
Pension and OPEB adjustments	[1]	9	(6)	3
Net unrealized (losses) gains on cash flow hedges	[1]	(47)	(10)
Net unrealized gain on cash flow hedges	[1]			2
Reclassification into earnings from cash flow hedges	[1]	6	6
Reclassification into earnings from cash flow hedges	[1]			8
Unrealized gains on available for sale securities	[1]	8	(3)	13
Other Comprehensive (Loss) Income, net of tax	[1]	(24)	(13)	26
Comprehensive Income		3,547	2,631	3,090
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests		(177)	(22)	5
Comprehensive (Loss) Income Attributable to Parent		$ 3,683	$ 2,653	$ 3,085
Income from continuing operations available to Duke Energy Corporation common stockholders
Basic and diluted (in usd per share)		$ 5.07	$ 3.73	$ 4.37
(Loss) Income from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic and diluted (in usd per share)		(0.01)	0.03	(0.01)
Net income available to Duke Energy Corporation common stockholders
Basic and diluted (in usd per share)		$ 5.06	$ 3.76	$ 4.36
Weighted average shares outstanding
Weighted average common shares outstanding – basic and diluted		729	708	700
Cost of natural gas
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		$ 627	$ 697	$ 632
Duke Energy Carolinas
Operating Revenues
Total operating revenues		7,395	7,300	7,302
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		1,804	1,821	1,822
Operation, maintenance and other		1,868	2,130	2,021
Depreciation and amortization		1,388	1,201	1,090
Property and other taxes		292	295	281
Impairment charges		17	192	0
Total operating expenses		5,369	5,639	5,214
(Losses) Gains on Sales of Other Assets and Other, net			(1)	1
Operating Income		2,026	1,660	2,089
Other Income and Expenses
Other income and expenses, net		151	153	199
Total other income and expenses		151	153	199
Interest Expense		463	439	422
Income (Loss) from Continuing Operations before Income Taxes		1,714	1,374	1,866
Income Tax Expense From Continuing Operations		311	303	652
Net Income Attributable to Parent		1,403	1,071	1,214
Other Comprehensive (Loss) Income, net of tax(a)
Reclassification into earnings from cash flow hedges			1
Reclassification into earnings from cash flow hedges				2
Other Comprehensive (Loss) Income, net of tax			1	2
Comprehensive (Loss) Income Attributable to Parent		1,403	1,072	1,216
Progress Energy
Operating Revenues
Total operating revenues		11,202	10,728	9,783
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		4,024	3,976	3,417
Operation, maintenance and other		2,495	2,613	2,301
Depreciation and amortization		1,845	1,619	1,285
Property and other taxes		561	529	503
Impairment charges		(24)	87	156
Total operating expenses		8,901	8,824	7,662
(Losses) Gains on Sales of Other Assets and Other, net			24	26
Operating Income		2,301	1,928	2,147
Other Income and Expenses
Other income and expenses, net		141	165	209
Total other income and expenses		141	165	209
Interest Expense		862	842	824
Income From Continuing Operations Before Income Taxes		1,580	1,251	1,532
Income Tax Expense From Continuing Operations		253	218	264
Net Income		1,327	1,033	1,268
Less: Net (Loss) Income Attributable to Noncontrolling Interests			6	10
Net Income Attributable to Parent		1,327	1,027	1,258
Other Comprehensive (Loss) Income, net of tax(a)
Pension and OPEB adjustments		2	5	4
Net unrealized (losses) gains on cash flow hedges		5	6
Net unrealized gain on cash flow hedges				5
Unrealized gains on available for sale securities		1	(1)	4
Other Comprehensive (Loss) Income, net of tax		8	10	13
Comprehensive Income		1,335	1,043	1,281
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests			6	10
Comprehensive (Loss) Income Attributable to Parent		1,335	1,037	1,271
Duke Energy Progress
Operating Revenues
Total operating revenues		5,957	5,699	5,129
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		2,012	1,892	1,609
Operation, maintenance and other		1,446	1,578	1,439
Depreciation and amortization		1,143	991	725
Property and other taxes		176	155	156
Impairment charges		12	33	19
Total operating expenses		4,789	4,649	3,948
(Losses) Gains on Sales of Other Assets and Other, net			9	4
Operating Income		1,168	1,059	1,185
Other Income and Expenses
Other income and expenses, net		100	87	115
Total other income and expenses		100	87	115
Interest Expense		306	319	293
Income (Loss) from Continuing Operations before Income Taxes		962	827	1,007
Income Tax Expense From Continuing Operations		157	160	292
Net Income Attributable to Parent		805	667	715
Other Comprehensive (Loss) Income, net of tax(a)
Comprehensive (Loss) Income Attributable to Parent		805	667	715
Duke Energy Florida
Operating Revenues
Total operating revenues		5,231	5,021	4,646
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		2,012	2,085	1,808
Operation, maintenance and other		1,034	1,025	853
Depreciation and amortization		702	628	560
Property and other taxes		392	374	347
Impairment charges		(36)	54	138
Total operating expenses		4,104	4,166	3,706
(Losses) Gains on Sales of Other Assets and Other, net			1	1
Operating Income		1,127	856	941
Other Income and Expenses
Other income and expenses, net		48	86	96
Total other income and expenses		48	86	96
Interest Expense		328	287	279
Income (Loss) from Continuing Operations before Income Taxes		847	655	758
Income Tax Expense From Continuing Operations		155	101	46
Net Income Attributable to Parent		692	554	712
Other Comprehensive (Loss) Income, net of tax(a)
Unrealized gains on available for sale securities		1	(1)	3
Other Comprehensive (Loss) Income, net of tax		1	(1)	3
Comprehensive (Loss) Income Attributable to Parent		693	553	715
Duke Energy Ohio
Operating Revenues
Regulated electric		1,456	1,450	1,373
Regulated natural gas		484	506	508
Nonregulated electric and other			1	42
Total operating revenues		1,940	1,957	1,923
Operating Expenses
Operation, maintenance and other		520	480	530
Depreciation and amortization		265	268	261
Property and other taxes		308	290	278
Impairment charges				1
Total operating expenses		1,576	1,563	1,604
(Losses) Gains on Sales of Other Assets and Other, net			(106)	1
Operating Income		364	288	320
Other Income and Expenses
Other income and expenses, net		24	23	23
Total other income and expenses		24	23	23
Interest Expense		109	92	91
Income (Loss) from Continuing Operations before Income Taxes		279	219	252
Income Tax Expense From Continuing Operations		40	43	59
Income From Continuing Operations		239	176	193
(Loss) Income From Discontinued Operations, net of tax		(1)		(1)
Net Income Attributable to Parent		238	176	192
Other Comprehensive (Loss) Income, net of tax(a)
Comprehensive (Loss) Income Attributable to Parent		238	176	192
Duke Energy Ohio | Cost of natural gas
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		95	113	107
Duke Energy Ohio | Electric Utilities and Infrastructure
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		388	412	369
Duke Energy Ohio | Electricity, Nonregulated
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas				58
Duke Energy Indiana
Operating Revenues
Total operating revenues		3,004	3,059	3,047
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		935	1,000	966
Operation, maintenance and other		790	788	743
Depreciation and amortization		525	520	458
Property and other taxes		69	78	76
Impairment charges			30	18
Total operating expenses		2,319	2,416	2,261
Operating Income		685	643	786
Other Income and Expenses
Other income and expenses, net		41	45	47
Total other income and expenses		41	45	47
Interest Expense		156	167	178
Income (Loss) from Continuing Operations before Income Taxes		570	521	655
Income Tax Expense From Continuing Operations		134	128	301
Net Income Attributable to Parent		436	393	354
Piedmont
Operating Revenues
Regulated natural gas		1,369	1,365	1,319
Nonregulated electric and other		12	10	9
Total operating revenues		1,381	1,375	1,328
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		532	584	524
Operation, maintenance and other		328	357	304
Depreciation and amortization		172	159	148
Property and other taxes		45	49	48
Impairment charges				7
Total operating expenses		1,077	1,149	1,031
Operating Income		304	226	297
Other Income and Expenses
Equity in earnings of unconsolidated affiliates		8	7	(6)
Other income and expenses, net		20	14	(11)
Total other income and expenses		28	21	(17)
Interest Expense		87	81	79
Income (Loss) from Continuing Operations before Income Taxes		245	166	201
Income Tax Expense From Continuing Operations		43	37	62
Net Income Attributable to Parent		202	129	139
Other Comprehensive (Loss) Income, net of tax(a)
Comprehensive (Loss) Income Attributable to Parent		$ 202	$ 129	$ 139
[1]	Tax impacts are insignificant for all periods presented.

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 3,683	$ 2,653	$ 3,085
Duke Energy Progress
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	805	667	715
Duke Energy Ohio
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 238	$ 176	$ 192

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 3,571	$ 2,644	$ 3,064
Other Comprehensive (Loss) Income, net of tax(a)
Pension and OPEB adjustments	[1]	9	(6)	3
Net unrealized (losses) gains on cash flow hedges	[1]	(47)	(10)
Net unrealized (losses) gains on cash flow hedges	[1]			2
Reclassification into earnings from cash flow hedges	[1]	6	6
Reclassification into earnings from cash flow hedges	[1]			8
Unrealized gains (losses) on available-for-sale securities	[1]	8	(3)	13
Other Comprehensive (Loss) Income, net of tax	[1]	(24)	(13)	26
Comprehensive Income		3,547	2,631	3,090
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests		(177)	(22)	5
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		3,724	2,653	3,085
Less: Preferred Dividends		41
Comprehensive (Loss) Income Attributable to Parent		$ 3,683	$ 2,653	$ 3,085
[1]	Tax impacts are insignificant for all periods presented.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 311	$ 442
Receivables (net of allowance for doubtful accounts)	1,066	962
Receivables of VIEs (net of allowance for doubtful accounts)	1,994	2,172
Inventory	3,232	3,084
Regulatory assets (includes amounts related to VIEs)	1,796	2,005
Other (including amounts related to VIEs)	764	1,049
Total current assets	9,163	9,714
Property, Plant and Equipment
Cost	147,654	134,458
Accumulated depreciation and amortization	(45,773)	(43,126)
Generation facilities to be retired, net	246	362
Net property, plant and equipment	102,127	91,694
Other Noncurrent Assets
Goodwill	19,303	19,303
Regulatory assets (includes amounts related to VIEs)	13,222	13,617
Nuclear decommissioning trust funds	8,140	6,720
Operating lease right-of-use assets, net	1,658
Investments in equity method unconsolidated affiliates	1,936	1,409
Other (including amounts related to VIEs)	3,289	2,935
Total other noncurrent assets	47,548	43,984
Total Assets	158,838	145,392
Current Liabilities
Accounts payable	3,487	3,487
Notes payable and commercial paper	3,135	3,410
Taxes accrued	392	577
Interest accrued	565	559
Current maturities of long-term debt (includes amounts related to VIEs)	3,141	3,406
Asset retirement obligations	881	919
Regulatory liabilities	784	598
Other	2,367	2,085
Total current liabilities	14,752	15,041
Long-Term Debt (includes amounts related to VIEs)	54,985	51,123
Other Noncurrent Liabilities
Deferred income taxes	8,878	7,806
Asset retirement obligations	12,437	9,548
Regulatory liabilities	15,264	14,834
Operating lease liabilities	1,432
Accrued pension and other post-retirement benefit costs	934	988
Investment tax credits	624	568
Other (includes amounts related to VIEs)	1,581	1,650
Total other noncurrent liabilities	41,150	35,394
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	40,881	40,795
Retained earnings	4,108	3,113
Accumulated other comprehensive (loss) income	(130)	(92)
Total Parent stockholders' equity	46,822	43,817
Noncontrolling interests	1,129	17
Total equity	47,951	43,834
Total Liabilities and Equity	158,838	145,392
Series A Preferred Stock
Equity
Preferred stock	973
Series B Preferred Stock
Equity
Preferred stock	989
Duke Energy Carolinas
Current Assets
Cash and cash equivalents	18	33
Receivables (net of allowance for doubtful accounts)	324	219
Receivables of VIEs (net of allowance for doubtful accounts)	642	699
Receivables from affiliated companies	114	182
Inventory	996	948
Regulatory assets (includes amounts related to VIEs)	550	520
Other (including amounts related to VIEs)	21	72
Total current assets	2,665	2,673
Property, Plant and Equipment
Cost	48,922	44,741
Accumulated depreciation and amortization	(16,525)	(15,496)
Net property, plant and equipment	32,397	29,245
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	3,360	3,457
Nuclear decommissioning trust funds	4,359	3,558
Operating lease right-of-use assets, net	123
Other (including amounts related to VIEs)	1,149	1,027
Total other noncurrent assets	8,991	8,042
Total Assets	44,053	39,960
Current Liabilities
Accounts payable	954	988
Accounts payable to affiliated companies	210	230
Notes payable to affiliated companies	29	439
Taxes accrued	46	171
Interest accrued	115	102
Current maturities of long-term debt (includes amounts related to VIEs)	458	6
Asset retirement obligations	206	290
Regulatory liabilities	255	199
Other	611	571
Total current liabilities	2,884	2,996
Long-Term Debt (includes amounts related to VIEs)	11,142	10,633
Long-Term Debt Payable to Affiliated Companies	300	300
Other Noncurrent Liabilities
Deferred income taxes	3,921	3,689
Asset retirement obligations	5,528	3,659
Regulatory liabilities	6,423	5,999
Operating lease liabilities	102
Accrued pension and other post-retirement benefit costs	84	99
Investment tax credits	231	231
Other (includes amounts related to VIEs)	627	671
Total other noncurrent liabilities	16,916	14,348
Commitments and Contingencies
Equity
Member's equity	12,818	11,689
Accumulated other comprehensive (loss) income	(7)	(6)
Total member's equity	12,811	11,683
Total Liabilities and Equity	44,053	39,960
Progress Energy
Current Assets
Cash and cash equivalents	48	67
Receivables (net of allowance for doubtful accounts)	220	220
Receivables of VIEs (net of allowance for doubtful accounts)	830	909
Receivables from affiliated companies	76	168
Notes receivable from affiliated companies	164
Inventory	1,423	1,459
Regulatory assets (includes amounts related to VIEs)	946	1,137
Other (including amounts related to VIEs)	210	125
Total current assets	3,917	4,085
Property, Plant and Equipment
Cost	55,070	50,260
Accumulated depreciation and amortization	(17,159)	(16,398)
Generation facilities to be retired, net	246	362
Net property, plant and equipment	38,157	34,224
Other Noncurrent Assets
Goodwill	3,655	3,655
Regulatory assets (includes amounts related to VIEs)	6,346	6,564
Nuclear decommissioning trust funds	3,782	3,162
Operating lease right-of-use assets, net	788
Other (including amounts related to VIEs)	1,049	974
Total other noncurrent assets	15,620	14,355
Total Assets	57,694	52,664
Current Liabilities
Accounts payable	1,104	1,172
Accounts payable to affiliated companies	310	360
Notes payable to affiliated companies	1,821	1,235
Taxes accrued	46	109
Interest accrued	228	246
Current maturities of long-term debt (includes amounts related to VIEs)	1,577	1,672
Asset retirement obligations	485	514
Regulatory liabilities	330	280
Other	902	821
Total current liabilities	6,803	6,409
Long-Term Debt (includes amounts related to VIEs)	17,907	17,089
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	4,462	3,941
Asset retirement obligations	5,986	4,897
Regulatory liabilities	5,225	5,049
Operating lease liabilities	697
Accrued pension and other post-retirement benefit costs	488	521
Other (includes amounts related to VIEs)	383	351
Total other noncurrent liabilities	17,241	14,759
Commitments and Contingencies
Equity
Additional paid-in capital	9,143	9,143
Retained earnings	6,465	5,131
Accumulated other comprehensive (loss) income	(18)	(20)
Total Parent stockholders' equity	15,590	14,254
Noncontrolling interests	3	3
Total equity	15,593	14,257
Total Liabilities and Equity	57,694	52,664
Duke Energy Progress
Current Assets
Cash and cash equivalents	22	23
Receivables (net of allowance for doubtful accounts)	123	75
Receivables of VIEs (net of allowance for doubtful accounts)	489	547
Receivables from affiliated companies	52	23
Inventory	934	954
Regulatory assets (includes amounts related to VIEs)	526	703
Other (including amounts related to VIEs)	60	62
Total current assets	2,206	2,387
Property, Plant and Equipment
Cost	34,603	31,459
Accumulated depreciation and amortization	(11,915)	(11,423)
Generation facilities to be retired, net	246	362
Net property, plant and equipment	22,934	20,398
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	4,152	4,111
Nuclear decommissioning trust funds	3,047	2,503
Operating lease right-of-use assets, net	387
Other (including amounts related to VIEs)	651	612
Total other noncurrent assets	8,237	7,226
Total Assets	33,377	30,011
Current Liabilities
Accounts payable	629	660
Accounts payable to affiliated companies	203	278
Notes payable to affiliated companies	66	294
Taxes accrued	17	53
Interest accrued	110	116
Current maturities of long-term debt (includes amounts related to VIEs)	1,006	603
Asset retirement obligations	485	509
Regulatory liabilities	236	178
Other	478	408
Total current liabilities	3,230	3,099
Long-Term Debt (includes amounts related to VIEs)	7,902	7,451
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	2,388	2,119
Asset retirement obligations	5,408	4,311
Regulatory liabilities	4,232	3,955
Operating lease liabilities	354
Accrued pension and other post-retirement benefit costs	238	237
Investment tax credits	137	142
Other (includes amounts related to VIEs)	92	106
Total other noncurrent liabilities	12,849	10,870
Commitments and Contingencies
Equity
Total member's equity	9,246	8,441
Total Liabilities and Equity	33,377	30,011
Duke Energy Florida
Current Assets
Cash and cash equivalents	17	36
Receivables (net of allowance for doubtful accounts)	96	143
Receivables of VIEs (net of allowance for doubtful accounts)	341	362
Receivables from affiliated companies		28
Notes receivable from affiliated companies	173
Inventory	489	504
Regulatory assets (includes amounts related to VIEs)	419	434
Other (including amounts related to VIEs)	58	46
Total current assets	1,593	1,553
Property, Plant and Equipment
Cost	20,457	18,792
Accumulated depreciation and amortization	(5,236)	(4,968)
Net property, plant and equipment	15,221	13,824
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	2,194	2,454
Nuclear decommissioning trust funds	734	659
Operating lease right-of-use assets, net	401
Other (including amounts related to VIEs)	311	311
Total other noncurrent assets	3,640	3,424
Total Assets	20,454	18,801
Current Liabilities
Accounts payable	474	511
Accounts payable to affiliated companies	131	91
Notes payable to affiliated companies		108
Taxes accrued	43	74
Interest accrued	75	75
Current maturities of long-term debt (includes amounts related to VIEs)	571	270
Asset retirement obligations		5
Regulatory liabilities	94	102
Other	415	406
Total current liabilities	1,803	1,642
Long-Term Debt (includes amounts related to VIEs)	7,416	7,051
Other Noncurrent Liabilities
Deferred income taxes	2,179	1,986
Asset retirement obligations	578	586
Regulatory liabilities	993	1,094
Operating lease liabilities	343
Accrued pension and other post-retirement benefit costs	218	254
Other (includes amounts related to VIEs)	136	93
Total other noncurrent liabilities	4,447	4,013
Commitments and Contingencies
Equity
Member's equity	6,789	6,097
Accumulated other comprehensive (loss) income	(1)	(2)
Total member's equity	6,788	6,095
Total Liabilities and Equity	20,454	18,801
Duke Energy Ohio
Current Assets
Cash and cash equivalents	17	21
Receivables (net of allowance for doubtful accounts)	84	102
Receivables from affiliated companies	92	114
Inventory	135	126
Regulatory assets (includes amounts related to VIEs)	49	33
Other (including amounts related to VIEs)	21	24
Total current assets	398	420
Property, Plant and Equipment
Cost	10,241	9,360
Accumulated depreciation and amortization	(2,843)	(2,717)
Net property, plant and equipment	7,398	6,643
Other Noncurrent Assets
Goodwill	920	920
Regulatory assets (includes amounts related to VIEs)	549	531
Operating lease right-of-use assets, net	21
Other (including amounts related to VIEs)	52	41
Total other noncurrent assets	1,542	1,492
Total Assets	9,338	8,555
Current Liabilities
Accounts payable	288	316
Accounts payable to affiliated companies	68	78
Notes payable to affiliated companies	312	274
Taxes accrued	219	202
Interest accrued	30	22
Current maturities of long-term debt (includes amounts related to VIEs)		551
Asset retirement obligations	1	6
Regulatory liabilities	64	57
Other	75	74
Total current liabilities	1,057	1,580
Long-Term Debt (includes amounts related to VIEs)	2,594	1,589
Long-Term Debt Payable to Affiliated Companies	25	25
Other Noncurrent Liabilities
Deferred income taxes	922	817
Asset retirement obligations	79	87
Regulatory liabilities	763	840
Operating lease liabilities	21
Accrued pension and other post-retirement benefit costs	100	79
Other (includes amounts related to VIEs)	94	93
Total other noncurrent liabilities	1,979	1,916
Commitments and Contingencies
Equity
Common stock	762	762
Additional paid-in capital	2,776	2,776
Retained earnings	145	(93)
Total Parent stockholders' equity	3,683	3,445
Total Liabilities and Equity	9,338	8,555
Duke Energy Indiana
Current Assets
Cash and cash equivalents	25	24
Receivables (net of allowance for doubtful accounts)	60	52
Receivables from affiliated companies	79	122
Inventory	517	422
Regulatory assets (includes amounts related to VIEs)	90	175
Other (including amounts related to VIEs)	60	35
Total current assets	831	830
Property, Plant and Equipment
Cost	16,305	15,443
Accumulated depreciation and amortization	(5,233)	(4,914)
Net property, plant and equipment	11,072	10,529
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	1,082	982
Operating lease right-of-use assets, net	57
Other (including amounts related to VIEs)	234	194
Total other noncurrent assets	1,373	1,176
Total Assets	13,276	12,535
Current Liabilities
Accounts payable	201	200
Accounts payable to affiliated companies	87	83
Notes payable to affiliated companies	30	167
Taxes accrued	49	43
Interest accrued	58	58
Current maturities of long-term debt (includes amounts related to VIEs)	503	63
Asset retirement obligations	189	109
Regulatory liabilities	55	25
Other	112	107
Total current liabilities	1,284	855
Long-Term Debt (includes amounts related to VIEs)	3,404	3,569
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	1,150	1,009
Asset retirement obligations	643	613
Regulatory liabilities	1,685	1,722
Operating lease liabilities	55
Accrued pension and other post-retirement benefit costs	148	115
Investment tax credits	164	147
Other (includes amounts related to VIEs)	18	16
Total other noncurrent liabilities	3,863	3,622
Commitments and Contingencies
Equity
Total member's equity	4,575	4,339
Total Liabilities and Equity	13,276	12,535
Piedmont
Current Assets
Receivables (net of allowance for doubtful accounts)	241	266
Receivables from affiliated companies	10	22
Inventory	72	70
Regulatory assets (includes amounts related to VIEs)	73	54
Other (including amounts related to VIEs)	28	19
Total current assets	424	431
Property, Plant and Equipment
Cost	8,446	7,486
Accumulated depreciation and amortization	(1,681)	(1,575)
Net property, plant and equipment	6,765	5,911
Other Noncurrent Assets
Goodwill	49	49
Regulatory assets (includes amounts related to VIEs)	290	303
Operating lease right-of-use assets, net	24
Investments in equity method unconsolidated affiliates	83	64
Other (including amounts related to VIEs)	121	52
Total other noncurrent assets	567	468
Total Assets	7,756	6,810
Current Liabilities
Accounts payable	215	203
Accounts payable to affiliated companies	3	38
Notes payable to affiliated companies	476	198
Taxes accrued	24	84
Interest accrued	33	31
Current maturities of long-term debt (includes amounts related to VIEs)		350
Regulatory liabilities	81	37
Other	67	58
Total current liabilities	899	999
Long-Term Debt (includes amounts related to VIEs)	2,384	1,788
Other Noncurrent Liabilities
Deferred income taxes	708	551
Asset retirement obligations	17	19
Regulatory liabilities	1,131	1,181
Operating lease liabilities	23
Accrued pension and other post-retirement benefit costs	3	4
Other (includes amounts related to VIEs)	148	177
Total other noncurrent liabilities	2,030	1,932
Commitments and Contingencies
Equity
Common stock	1,310	1,160
Retained earnings	1,133	931
Total Parent stockholders' equity	2,443	2,091
Total Liabilities and Equity	$ 7,756	$ 6,810

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts - receivables	$ 22	$ 16
Regulatory Assets: Current	1,796	2,005
Current Assets: Other	764	1,049
Other Noncurrent Assets: Regulatory assets	13,222	13,617
Other Noncurrent Assets: Other	3,289	2,935
Current maturities of long-term debt	3,141	3,406
Long-Term Debt	54,985	51,123
Other Noncurrent Liabilities: Other	$ 1,581	$ 1,650
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	733,000,000	727,000,000
Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 54	$ 55
Regulatory Assets: Current	52	52
Current Assets: Other	242	162
Other Noncurrent Assets: Regulatory assets	989	1,041
Other Noncurrent Assets: Other	110	261
Current maturities of long-term debt	216	227
Long-Term Debt	3,997	3,998
Other Noncurrent Liabilities: Other	$ 228	212
Series A Preferred Stock
Preferred stock, par value (in usd per share)	$ 0.001
Preferred stock, depositary shares authorized	40,000,000
Preferred stock, depositary shares outstanding	40,000,000
Series B Preferred Stock
Preferred stock, par value (in usd per share)	$ 0.001
Preferred stock, depositary shares authorized	1,000,000
Preferred stock, depositary shares outstanding	1,000,000
Duke Energy Carolinas
Allowance for doubtful accounts - receivables	$ 3	2
Regulatory Assets: Current	550	520
Current Assets: Other	21	72
Other Noncurrent Assets: Regulatory assets	3,360	3,457
Other Noncurrent Assets: Other	1,149	1,027
Current maturities of long-term debt	458	6
Long-Term Debt	11,142	10,633
Other Noncurrent Liabilities: Other	627	671
Duke Energy Carolinas | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	7	7
Progress Energy
Allowance for doubtful accounts - receivables	7	5
Regulatory Assets: Current	946	1,137
Current Assets: Other	210	125
Other Noncurrent Assets: Regulatory assets	6,346	6,564
Other Noncurrent Assets: Other	1,049	974
Current maturities of long-term debt	1,577	1,672
Long-Term Debt	17,907	17,089
Other Noncurrent Liabilities: Other	$ 383	$ 351
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Progress Energy | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 9	$ 8
Regulatory Assets: Current	52	52
Current Assets: Other	39	39
Other Noncurrent Assets: Regulatory assets	989	1,041
Current maturities of long-term debt	54	53
Long-Term Debt	1,632	1,636
Duke Energy Progress
Allowance for doubtful accounts - receivables	3	2
Regulatory Assets: Current	526	703
Current Assets: Other	60	62
Other Noncurrent Assets: Regulatory assets	4,152	4,111
Other Noncurrent Assets: Other	651	612
Current maturities of long-term debt	1,006	603
Long-Term Debt	7,902	7,451
Other Noncurrent Liabilities: Other	92	106
Duke Energy Progress | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	5	5
Duke Energy Florida
Allowance for doubtful accounts - receivables	3	3
Regulatory Assets: Current	419	434
Current Assets: Other	58	46
Other Noncurrent Assets: Regulatory assets	2,194	2,454
Other Noncurrent Assets: Other	311	311
Current maturities of long-term debt	571	270
Long-Term Debt	7,416	7,051
Other Noncurrent Liabilities: Other	136	93
Duke Energy Florida | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	4	3
Regulatory Assets: Current	52	52
Current Assets: Other	39	39
Other Noncurrent Assets: Regulatory assets	989	1,041
Current maturities of long-term debt	54	53
Long-Term Debt	1,307	1,336
Duke Energy Ohio
Allowance for doubtful accounts - receivables	4	2
Regulatory Assets: Current	49	33
Current Assets: Other	21	24
Other Noncurrent Assets: Regulatory assets	549	531
Other Noncurrent Assets: Other	52	41
Current maturities of long-term debt		551
Long-Term Debt	2,594	1,589
Other Noncurrent Liabilities: Other	$ 94	$ 93
Common stock, par value	$ 8.50	$ 8.50
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares outstanding	90,000,000	90,000,000
Duke Energy Indiana
Allowance for doubtful accounts - receivables	$ 3	$ 2
Regulatory Assets: Current	90	175
Current Assets: Other	60	35
Other Noncurrent Assets: Regulatory assets	1,082	982
Other Noncurrent Assets: Other	234	194
Current maturities of long-term debt	503	63
Long-Term Debt	3,404	3,569
Other Noncurrent Liabilities: Other	18	16
Piedmont
Allowance for doubtful accounts - receivables	6	2
Regulatory Assets: Current	73	54
Current Assets: Other	28	19
Other Noncurrent Assets: Regulatory assets	290	303
Other Noncurrent Assets: Other	121	52
Current maturities of long-term debt		350
Long-Term Debt	2,384	1,788
Other Noncurrent Liabilities: Other	$ 148	$ 177
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net income	$ 3,571	$ 2,644	$ 3,064
Net Income Attributable to Parent	3,748	2,666	3,059
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	5,176	4,696	4,046
Equity component of AFUDC	(139)	(221)	(237)
Losses (Gains) on sales of other assets	4	88	(33)
Impairment charges	(8)	402	282
Deferred income taxes	806	1,079	1,433
Equity in earnings of unconsolidated affiliates	(162)	(83)	(119)
Accrued pension and other post-retirement benefit costs	24	61	8
Contributions to qualified pension plans	(77)	(141)	(19)
Payments for asset retirement obligations	(746)	(533)	(571)
Payment for the disposal of other assets		(105)
Provision for rate refunds	60	425
Refund of AMT credit carryforwards	573
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(48)	22	18
Receivables	78	(345)	(83)
Inventory	(122)	156	268
Other current assets	10	(721)	(400)
Increase (decrease) in
Accounts payable	(164)	479	(204)
Taxes accrued	(224)	23	149
Other current liabilities	172	270	(482)
Other assets	(520)	(971)	(436)
Other liabilities	(55)	(39)	(60)
Net cash provided by (used in) operating activities	8,209	7,186	6,624
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(11,122)	(9,389)	(8,052)
Contributions to equity method investments	(324)	(416)	(414)
Return of investment capital	11	137	281
Purchases of debt and equity securities	(3,348)	(3,762)	(4,071)
Proceeds from sales and maturities of debt and equity securities	3,343	3,747	4,098
Other	(517)	(377)	(284)
Net cash used in investing activities	(11,957)	(10,060)	(8,442)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	7,091	5,299	6,909
Net proceeds from Issuance of Preferred Stock and Preference Stock	1,962
Proceeds from Issuance of Common Stock	384	1,838
Payments for the redemption of long-term debt	(3,476)	(2,906)	(2,316)
Proceeds from the issuance of short-term debt with original maturities greater than 90 days	397	472	319
Payments for the redemption of short-term debt with original maturities greater than 90 days	(479)	(282)	(272)
Notes payable and commercial paper	(298)	981	(409)
Contributions from noncontrolling interests	843	41
Dividends paid	(2,668)	(2,471)	(2,450)
Other	(26)	(12)	1
Net cash provided by financing activities	3,730	2,960	1,782
Net (decrease) increase in cash, cash equivalents, and restricted cash	(18)	86	(36)
Cash, cash equivalents, and restricted cash at beginning of period	591	505	541
Cash, cash equivalents, and restricted cash at end of period	573	591	505
Cash and cash equivalents at beginning of period	442
Cash and cash equivalents at end of period	311	442
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	2,195	2,086	1,963
Cash (received from) paid for income taxes	(651)	(266)	4
Significant non-cash transactions:
Accrued capital expenditures	1,356	1,112	1,032
Non-cash dividends	108	107
Duke Energy Carolinas
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	1,403	1,071	1,214
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,671	1,487	1,409
Equity component of AFUDC	(42)	(73)	(106)
Losses (Gains) on sales of other assets		1	(1)
Impairment charges	17	192
Deferred income taxes	133	305	410
Accrued pension and other post-retirement benefit costs	(5)	4	(4)
Contributions to qualified pension plans	(7)	(46)
Payments for asset retirement obligations	(278)	(230)	(271)
Provision for rate refunds	36	182
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(8)	2	9
Receivables	(21)	(86)	(9)
Receivables from affiliated companies	68	(87)	68
Inventory	(48)	25	78
Other current assets	(73)	(161)	7
Increase (decrease) in
Accounts payable	(50)	168	23
Accounts payable to affiliated companies	(20)	21	(38)
Taxes accrued	(127)	(65)	86
Other current liabilities	127	89	(161)
Other assets	(31)	(179)	(49)
Other liabilities	(36)	(90)	(31)
Net cash provided by (used in) operating activities	2,709	2,530	2,634
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,714)	(2,706)	(2,524)
Purchases of debt and equity securities	(1,658)	(1,810)	(2,124)
Proceeds from sales and maturities of debt and equity securities	1,658	1,810	2,128
Notes receivable from affiliated companies			66
Other	(204)	(147)	(109)
Net cash used in investing activities	(2,918)	(2,853)	(2,563)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	886	1,983	569
Payments for the redemption of long-term debt	(6)	(1,205)	(116)
Notes payable to affiliated companies	(410)	335	104
Distributions to parent	(275)	(750)	(625)
Other	(1)	(23)	(1)
Net cash provided by financing activities	194	340	(69)
Net (decrease) increase in cash and cash equivalents	(15)	17	2
Cash and cash equivalents at beginning of period	33	16	14
Cash and cash equivalents at end of period	18	33	16
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	433	452	398
Cash (received from) paid for income taxes	122	89	193
Significant non-cash transactions:
Accrued capital expenditures	347	302	315
Progress Energy
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net income	1,327	1,033	1,268
Net Income Attributable to Parent	1,327	1,027	1,258
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	2,207	1,987	1,516
Equity component of AFUDC	(66)	(104)	(92)
Losses (Gains) on sales of other assets		(24)	(28)
Impairment charges	(24)	87	156
Deferred income taxes	433	358	703
Accrued pension and other post-retirement benefit costs	20	24	(28)
Contributions to qualified pension plans	(57)	(45)
Payments for asset retirement obligations	(412)	(230)	(248)
Provision for rate refunds	15	122
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(34)	18
Receivables	47	(207)	(89)
Receivables from affiliated companies	81	(137)	71
Inventory	62	121	125
Other current assets	184	(12)	(397)
Increase (decrease) in
Accounts payable	(4)	217	(260)
Accounts payable to affiliated companies	(50)	109	(97)
Taxes accrued	(74)	8	17
Other current liabilities	25	129	(166)
Other assets	(336)	(876)	(300)
Other liabilities	(135)	(34)	(98)
Net cash provided by (used in) operating activities	3,209	2,544	2,053
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(3,952)	(3,854)	(3,152)
Purchases of debt and equity securities	(1,511)	(1,753)	(1,806)
Proceeds from sales and maturities of debt and equity securities	1,504	1,769	1,824
Notes receivable from affiliated companies	(164)	240	(160)
Other	(190)	(162)	(59)
Net cash used in investing activities	(4,313)	(3,760)	(3,353)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	2,187	1,833	2,118
Payments for the redemption of long-term debt	(1,667)	(771)	(813)
Notes payable to affiliated companies	586	430	100
Dividends to parent		(250)	(124)
Other	12	(1)	(4)
Net cash provided by financing activities	1,118	1,241	1,277
Net (decrease) increase in cash, cash equivalents, and restricted cash	14	25	(23)
Cash, cash equivalents, and restricted cash at beginning of period	112	87	110
Cash, cash equivalents, and restricted cash at end of period	126	112	87
Cash and cash equivalents at beginning of period	67
Cash and cash equivalents at end of period	48	67
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	892	798	773
Cash (received from) paid for income taxes	(79)	(348)	(146)
Significant non-cash transactions:
Accrued capital expenditures	447	478	391
Equitization of certain notes payable to affiliates			1,047
Dividend to parent related to a legal entity restructuring			547
Duke Energy Progress
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	805	667	715
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,329	1,183	936
Equity component of AFUDC	(60)	(57)	(47)
Losses (Gains) on sales of other assets		(9)	(5)
Impairment charges	12	33	19
Deferred income taxes	197	236	384
Accrued pension and other post-retirement benefit costs	4	15	(20)
Contributions to qualified pension plans	(3)	(25)
Payments for asset retirement obligations	(390)	(195)	(192)
Provision for rate refunds	12	122
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(6)	5	(4)
Receivables	21	(107)	(58)
Receivables from affiliated companies	(29)	(20)	2
Inventory	20	63	59
Other current assets	101	(201)	(75)
Increase (decrease) in
Accounts payable	32	219	(230)
Accounts payable to affiliated companies	(75)	99	(48)
Taxes accrued	(46)	(11)	(39)
Other current liabilities	68	46	(131)
Other assets	(198)	(447)	(53)
Other liabilities	29	12	(18)
Net cash provided by (used in) operating activities	1,823	1,628	1,195
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,108)	(2,220)	(1,715)
Purchases of debt and equity securities	(842)	(1,236)	(1,249)
Proceeds from sales and maturities of debt and equity securities	810	1,206	1,207
Notes receivable from affiliated companies			165
Other	(119)	(95)	(51)
Net cash used in investing activities	(2,259)	(2,345)	(1,643)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	1,269	845	812
Payments for the redemption of long-term debt	(605)	(3)	(470)
Notes payable to affiliated companies	(228)	54	240
Distributions to parent		(175)	(124)
Other	(1)	(1)	(1)
Net cash provided by financing activities	435	720	457
Net (decrease) increase in cash and cash equivalents	(1)	3	9
Cash and cash equivalents at beginning of period	23	20	11
Cash and cash equivalents at end of period	22	23	20
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	331	303	291
Cash (received from) paid for income taxes	(30)	(112)	59
Significant non-cash transactions:
Accrued capital expenditures	175	220	191
Duke Energy Florida
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	692	554	712
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	869	793	570
Equity component of AFUDC	(6)	(47)	(45)
Losses (Gains) on sales of other assets		(1)	(1)
Impairment charges	(36)	54	138
Deferred income taxes	180	159	245
Accrued pension and other post-retirement benefit costs	11	5	(13)
Contributions to qualified pension plans	(53)	(20)
Payments for asset retirement obligations	(22)	(35)	(56)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(33)	7	5
Receivables	26	(100)	(38)
Receivables from affiliated companies	17	(26)
Inventory	42	58	66
Other current assets	156	59	(138)
Increase (decrease) in
Accounts payable	(36)	(1)	(32)
Accounts payable to affiliated companies	40	17	(51)
Taxes accrued	(31)	40	1
Other current liabilities	(36)	82	(37)
Other assets	(135)	(428)	(229)
Other liabilities	(167)	(61)	(82)
Net cash provided by (used in) operating activities	1,478	1,109	1,015
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,844)	(1,634)	(1,437)
Purchases of debt and equity securities	(669)	(517)	(557)
Proceeds from sales and maturities of debt and equity securities	695	563	617
Notes receivable from affiliated companies	(173)	313	(313)
Other	(67)	(65)	(7)
Net cash used in investing activities	(2,058)	(1,340)	(1,697)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	918	988	1,306
Payments for the redemption of long-term debt	(262)	(769)	(342)
Notes payable to affiliated companies	(108)	108	(297)
Distributions to parent		(75)
Other	13	1	(1)
Net cash provided by financing activities	561	253	666
Net (decrease) increase in cash, cash equivalents, and restricted cash	(19)	22	(16)
Cash, cash equivalents, and restricted cash at beginning of period	75	53	69
Cash, cash equivalents, and restricted cash at end of period	56	75	53
Cash and cash equivalents at beginning of period	36
Cash and cash equivalents at end of period	17	36
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	332	270	274
Cash (received from) paid for income taxes	1	(120)	(197)
Significant non-cash transactions:
Accrued capital expenditures	272	258	199
Duke Energy Ohio
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	238	176	192
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	269	271	265
Equity component of AFUDC	(13)	(11)	(11)
Losses (Gains) on sales of other assets		106	(1)
Impairment charges			1
Deferred income taxes	81	25	90
Accrued pension and other post-retirement benefit costs	2	3	2
Contributions to qualified pension plans	(2)		(4)
Payments for asset retirement obligations	(8)	(3)	(7)
Provision for rate refunds	7	24
(Increase) decrease in
Receivables	20	(33)	2
Receivables from affiliated companies	22	19	(4)
Inventory	(9)	7	6
Other current assets	(5)	16	(22)
Increase (decrease) in
Accounts payable	(17)	(19)	12
Accounts payable to affiliated companies	(10)	16	(1)
Taxes accrued	17	12	11
Other current liabilities	1	14	(19)
Other assets	(22)	(26)	(28)
Other liabilities	(45)	(27)	(5)
Net cash provided by (used in) operating activities	526	570	479
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(952)	(827)	(686)
Notes receivable from affiliated companies		14	80
Other	(68)	(89)	(41)
Net cash used in investing activities	(1,020)	(902)	(647)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	1,003	99	182
Payments for the redemption of long-term debt	(551)	(3)	(2)
Notes payable to affiliated companies	38	245	13
Dividends to parent			(25)
Other			(1)
Net cash provided by financing activities	490	341	167
Net (decrease) increase in cash and cash equivalents	(4)	9	(1)
Cash and cash equivalents at beginning of period	21	12	13
Cash and cash equivalents at end of period	17	21	12
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	97	87	85
Cash (received from) paid for income taxes	(37)	(6)	(8)
Significant non-cash transactions:
Accrued capital expenditures	109	95	82
Transfer of ownership interest of certain equity method investees to parent		106
Duke Energy Indiana
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	436	393	354
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	531	524	462
Equity component of AFUDC	(18)	(32)	(28)
Impairment charges		30	18
Deferred income taxes	156	95	152
Accrued pension and other post-retirement benefit costs	6	7	2
Contributions to qualified pension plans	(2)	(8)
Payments for asset retirement obligations	(48)	(69)	(45)
Provision for rate refunds		53
(Increase) decrease in
Receivables	(8)	7	59
Receivables from affiliated companies	41	3	(11)
Inventory	(95)	28	54
Other current assets	76	(25)	28
Increase (decrease) in
Accounts payable	(10)	37	(86)
Accounts payable to affiliated companies	4	5	4
Taxes accrued	(25)	(52)	64
Other current liabilities	15	14	(10)
Other assets	(71)	29	(28)
Other liabilities	9	(33)	(20)
Net cash provided by (used in) operating activities	997	1,006	969
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(876)	(832)	(840)
Purchases of debt and equity securities	(26)	(48)	(20)
Proceeds from sales and maturities of debt and equity securities	20	44	7
Notes receivable from affiliated companies			86
Other	(49)	18	(65)
Net cash used in investing activities	(931)	(818)	(832)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	485
Payments for the redemption of long-term debt	(213)	(3)	(5)
Notes payable to affiliated companies	(137)	6	161
Distributions to parent	(200)	(175)	(300)
Other		(1)	(1)
Net cash provided by financing activities	(65)	(173)	(145)
Net (decrease) increase in cash and cash equivalents	1	15	(8)
Cash and cash equivalents at beginning of period	24	9	17
Cash and cash equivalents at end of period	25	24	9
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	150	162	179
Cash (received from) paid for income taxes	(6)	75	117
Significant non-cash transactions:
Accrued capital expenditures	102	88	125
Piedmont
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	202	129	139
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	174	161	151
Impairment charges			7
Deferred income taxes	136	(31)	154
Equity in earnings of unconsolidated affiliates	(8)	(7)	6
Accrued pension and other post-retirement benefit costs	(9)	(4)	23
Contributions to qualified pension plans	(1)		(11)
Provision for rate refunds	2	43
(Increase) decrease in
Receivables	28	7	(40)
Receivables from affiliated companies	12	(15)
Inventory	(2)	(4)
Other current assets	(25)	71	(20)
Increase (decrease) in
Accounts payable	(7)	15	(13)
Accounts payable to affiliated companies	(35)	25	5
Taxes accrued	(60)	65	(48)
Other current liabilities	1	21	(9)
Other assets	9	6	7
Other liabilities	(8)	(4)	(2)
Net cash provided by (used in) operating activities	409	478	349
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,053)	(721)	(585)
Contributions to equity method investments	(16)		(12)
Return of investment capital	4	3	2
Other	(14)	(10)	(6)
Net cash used in investing activities	(1,083)	(731)	(603)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	596	100	250
Payments for the redemption of long-term debt	(350)		(35)
Notes payable and commercial paper			(330)
Notes payable to affiliated companies	278	(166)	364
Contribution from parent	150	300
Other			(1)
Net cash provided by financing activities	674	234	248
Net (decrease) increase in cash and cash equivalents		(19)	(6)
Cash and cash equivalents at beginning of period		19	25
Cash and cash equivalents at end of period			19
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	84	79	78
Cash (received from) paid for income taxes	(31)	(16)	(12)
Significant non-cash transactions:
Accrued capital expenditures	$ 109	$ 96	34
Transfer of ownership interest of certain equity method investees to parent			$ 149

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions		Total		Preferred Stock	Common Stock	Additional Paid In Capital	Retained Earnings		Net Gains (Losses) on Cash Flow Hedges	Net Gains (Losses) on Cash Flow Hedges		Net Unrealized Gains (Losses) on Available-for-Sale Securities		Pension and OPEB Adjustments		Common Stockholders' Equity		Noncontrolling Interests		Duke Energy Carolinas	Duke Energy CarolinasMembers Equity	Duke Energy CarolinasNet Gains (Losses) on Cash Flow Hedges	Duke Energy CarolinasNet Gains (Losses) on Cash Flow Hedges	Progress Energy		Progress EnergyAdditional Paid In Capital		Progress EnergyRetained Earnings		Progress EnergyNet Gains (Losses) on Cash Flow Hedges	Progress EnergyNet Gains (Losses) on Cash Flow Hedges		Progress EnergyNet Unrealized Gains (Losses) on Available-for-Sale Securities		Progress EnergyPension and OPEB Adjustments		Progress EnergyCommon Stockholders' Equity		Progress EnergyNoncontrolling Interests		Duke Energy Progress	Duke Energy ProgressMembers Equity	Duke Energy Florida		Duke Energy FloridaMembers Equity		Duke Energy FloridaNet Unrealized Gains (Losses) on Available-for-Sale Securities		Duke Energy Ohio	Duke Energy OhioCommon Stock	Duke Energy OhioAdditional Paid In Capital	Duke Energy OhioRetained Earnings	Duke Energy Indiana	Duke Energy IndianaMembers Equity	Piedmont	PiedmontCommon Stock	PiedmontRetained Earnings	Series A Preferred Stock	[7]	Series A Preferred StockPreferred Stock	[7]	Series A Preferred StockCommon Stockholders' Equity	[7]	Series B Preferred Stock	[8]	Series B Preferred StockPreferred Stock	[8]	Series B Preferred StockCommon Stockholders' Equity	[8]
Beginning Balance (parent) at Dec. 31, 2016		$ 41,041			$ 1	$ 38,741	$ 2,384		$ (20)			$ (1)		$ (72)		$ 41,033		$ 8						$ 11,807		$ 8,094		$ 3,764		$ (23)			$ 1		$ (16)		$ 11,820		$ (13)
Beginning Members' Equity at Dec. 31, 2016																				$ 10,772	$ 10,781	$ (9)																				$ 7,358	$ 4,900		$ 4,899		$ 1							$ 4,067
Beginning Balance (Attributable to Parent) at Dec. 31, 2016																																																	$ 2,996	$ 762	$ 2,695	$ (461)			$ 1,672	$ 860	$ 812
Balance (in shares) at Dec. 31, 2016					700,000,000
Net income		3,064					3,059									3,059		5						1,268				1,258									1,258		10
Net Income Attributable to Parent		3,059																		1,214	1,214			1,258																	$ 715	715	712		712				192			192	$ 354	354	139		139
Other comprehensive income (loss), net of tax		26	[1]						$ 10			13		3		26				2		$ 2		13						$ 5			4		4		13						3				3
Stock issuances		51				51										51
Distributions/Dividends to parent		(2,450)					(2,450)									(2,450)				(625)	(625)			(672)	[2]			(672)	[2]								(672)	[2]				(124)							(25)		(25)			(300)
Distributions to noncontrolling interest in subsidiaries		(2)																(2)
Equitization of certain notes payable to affiliates																								1,047		1,047											1,047
Other		7	[3]				20	[3]								20	[3]	(13)	[3]	(2)	(2)			2		2											2						3		3										(149)		(149)
Balance (in shares) at Dec. 31, 2017					700,000,000
Ending Balance (parent) at Dec. 31, 2017		41,737			$ 1	38,792	3,013			$ (10)		12		(69)		41,739		(2)						13,465		9,143		4,350			$ (18)		5		(12)		13,468		(3)
Ending member's equity at Dec. 31, 2017																				11,361	11,368		$ (7)																			7,949	5,618		5,614		4							4,121
Ending Balance (Attributable to Parent) at Dec. 31, 2017																																																	3,163	762	2,670	(269)			1,662	860	802
Net income		2,644					2,666									2,666		(22)						1,033				1,027									1,027		6
Net Income Attributable to Parent		2,666																		1,071	1,071			1,027																	667	667	554		554				176			176	393	393	129		129
Contribution from parent																																																	$ 106		106				(300)	(300)
Other comprehensive income (loss), net of tax		(13)	[1]							(4)		(3)		(6)		(13)				1			1	10							6		(1)		5		10						(1)				(1)
Stock issuances, shares					27,000,000
Stock issuances		2,003				2,003										2,003
Distributions/Dividends to parent		(2,578)					(2,578)									(2,578)				(750)	(750)			(250)				(250)									(250)					(175)	(75)		(75)									(175)
Contribution from parent																																																							$ 300
Distributions to noncontrolling interest in subsidiaries		(1)																(1)						(1)															(1)
Other		$ 42	[4]				12	[4]				(12)	[4]					42	[4]					$ 0	[5]	0	[5]	4	[5]				(5)	[5]			(1)	[5]	1	[5]			(1)	[6]	4	[6]	(5)	[6]
Balance (in shares) at Dec. 31, 2018		727,000,000			727,000,000																			100																									90,000,000						100
Ending Balance (parent) at Dec. 31, 2018		$ 43,834			$ 1	40,795	3,113			(14)		(3)		(75)		43,817		17						$ 14,257		9,143		5,131			(12)		(1)		(7)		14,254		3
Ending member's equity at Dec. 31, 2018																				11,683	11,689		(6)																		8,441	8,441	6,095		6,097		(2)						4,339	4,339
Ending Balance (Attributable to Parent) at Dec. 31, 2018		43,817																						14,254																									$ 3,445	762	2,776	(93)			$ 2,091	1,160	931
Net income		3,571																						1,327				1,327									1,327		0
Net income		3,530					3,707									3,707		(177)
Net Income Attributable to Parent		3,748																		1,403	1,403			1,327																	805	805	692		692				$ 238			238	436	436	202		202
Contribution from parent																																																							(150)	(150)
Other comprehensive income (loss), net of tax		(24)	[1]							(41)		8		9		(24)								8							5		1		2		8						1				1
Stock issuances, shares					6,000,000
Stock issuances		552				552										552																																										$ 973		$ 973		$ 973		$ 989		$ 989		$ 989
Distributions/Dividends to parent		(2,735)					(2,735)									(2,735)				(275)	(275)																																	(200)
Contribution from parent																																																							$ 150
Sale of noncontrolling interest	[9]	407				(466)				10						(456)		863
Contribution from noncontrolling interest		428																428
Distributions to noncontrolling interest in subsidiaries		(4)																(4)
Other		$ 1	[10]				23	[10]		(6)	[10]	(2)	[10]	(16)	[10]	(1)	[10]	2	[10]	0	1		(1)	$ 1	[11]			7	[11]		(3)	[11]	(1)	[11]	(2)	[11]	1	[11]
Balance (in shares) at Dec. 31, 2019		733,000,000			733,000,000																			100																									90,000,000						100
Ending Balance (parent) at Dec. 31, 2019		$ 47,951		$ 1,962	$ 1	$ 40,881	$ 4,108			$ (51)		$ 3		$ (82)		$ 46,822		$ 1,129						$ 15,593		$ 9,143		$ 6,465			$ (10)		$ (1)		$ (7)		$ 15,590		$ 3
Ending member's equity at Dec. 31, 2019																				$ 12,811	$ 12,818		$ (7)																		$ 9,246	$ 9,246	$ 6,788		$ 6,789		$ (1)						$ 4,575	$ 4,575
Ending Balance (Attributable to Parent) at Dec. 31, 2019		$ 46,822																						$ 15,590																									$ 3,683	$ 762	$ 2,776	$ 145			$ 2,443	$ 1,310	$ 1,133
[1]	Tax impacts are insignificant for all periods presented.
[2]	Includes a $547 million
[3]	Retained Earnings relates to a cumulative-effect adjustment due to implementation of a new accounting standard related to stock-based compensation and the associated income taxes. See Note 1 to the Consolidated Financial Statements for additional information. Noncontrolling Interests relates to the purchase of remaining interest in REC Solar.
[4]	Amounts in Retained Earnings and AOCI represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement. See Note 1 for more information. Amount in Noncontrolling Interests primarily relates to tax equity financing activity in the Commercial Renewables segment.
[5]	Amounts in Retained Earnings and AOCI represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement. See Note 1 for more information.
[6]	Amounts represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement. See Note 1 for more information.
[7]	Duke Energy issued 40 million depositary shares of preferred stock, series A, in the first quarter of 2019.
[8]	Duke Energy issued 1 million shares of preferred stock, series B, in the third quarter of 2019.
[9]	See Note 3 for additional discussion of the transaction. (f) Amounts in Retained Earnings and AOCI primarily represent impacts to accumulated other comprehensive income due to implementation of a new accounting standard related to Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.
[10]	Amounts in Retained Earnings and AOCI primarily represent impacts to accumulated other comprehensive income due to implementation of a new accounting standard related to Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.
[11]	Amounts in Retained Earnings and AOCI primarily represent impacts to accumulated other comprehensive income due to implementation of a new accounting standard related to Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parentheticals) - USD ($) shares in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2017
Progress Energy
Non-cash dividend			$ 547
Preferred Stock | Series A Preferred Stock
Stock issuances, shares		40
Preferred Stock | Series B Preferred Stock
Stock issuances, shares	1

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Index to Combined Notes To Consolidated Financial Statements The notes to the consolidated financial statements are a combined presentation. The following table indicates the registrants to which the notes apply. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Duke Energy • • • • • • • • • • • • • • • • • • • • • • • • • • Duke Energy Carolinas • • • • • • • • • • • • • • • • • • • • • • • Progress Energy • • • • • • • • • • • • • • • • • • • • • • Duke Energy Progress • • • • • • • • • • • • • • • • • • • • • • Duke Energy Florida • • • • • • • • • • • • • • • • • • • • • • Duke Energy Ohio • • • • • • • • • • • • • • • • • • • • • Duke Energy Indiana • • • • • • • • • • • • • • • • • • • • • • • Piedmont • • • • • • • • • • • • • • • • • • • • • • Tables within the notes may not sum across due to (i) Progress Energy's consolidation of Duke Energy Progress, Duke Energy Florida and other subsidiaries that are not registrants and (ii) subsidiaries that are not registrants but included in the consolidated Duke Energy balances. Nature of Operations and Basis of Consolidation Duke Energy is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the FERC and other regulatory agencies listed below. Duke Energy operates in the U.S. primarily through its direct and indirect subsidiaries. Certain Duke Energy subsidiaries are also subsidiary registrants, including Duke Energy Carolinas; Progress Energy; Duke Energy Progress; Duke Energy Florida; Duke Energy Ohio; Duke Energy Indiana and Piedmont. When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its separate Subsidiary Registrants, which along with Duke Energy, are collectively referred to as the Duke Energy Registrants. The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Consolidated Financial Statements. However, none of the Subsidiary Registrants make any representation as to information related solely to Duke Energy or the Subsidiary Registrants of Duke Energy other than itself. These Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries or VIEs where the respective Duke Energy Registrants have control. See Note 18 for additional information on VIEs. These Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. See Note 9 for additional information on joint ownership. Substantially all of the Subsidiary Registrants' operations qualify for regulatory accounting. Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Progress Energy is a public utility holding company, which conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Progress Energy is subject to regulation by FERC and other regulatory agencies listed below. Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the FPSC, NRC and FERC. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers and recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky. References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the PUCO, KPSC and FERC. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the IURC and FERC. Piedmont is a regulated public utility primarily engaged in the distribution of natural gas in portions of North Carolina, South Carolina and Tennessee. Piedmont is subject to the regulatory provisions of the NCUC, PSCSC, TPUC and FERC. Certain prior year amounts have been reclassified to conform to the current year presentation. Other Current Assets and Liabilities The following table provides a description of amounts included in Other within Current Assets or Current Liabilities that exceed 5% of total Current Assets or Current Liabilities on the Duke Energy Registrants' Consolidated Balance Sheets at either December 31, 2019 , or 2018 . December 31, (in millions) Location 2019 2018 Duke Energy Taxes receivable Current Assets $ 357 $ 729 Accrued compensation Current Liabilities 862 793 Duke Energy Carolinas Accrued compensation Current Liabilities $ 271 $ 251 Other accrued liabilities Current Liabilities 147 55 Progress Energy Customer deposits Current Liabilities $ 354 $ 345 Duke Energy Florida Customer deposits Current Liabilities $ 209 $ 208 Other accrued liabilities Current Liabilities 89 85 Duke Energy Indiana Income taxes receivable Current Assets $ 44 $ 9 Customer deposits Current Liabilities 49 47 Discontinued Operations Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these consolidated financial statements exclude amounts related to discontinued operations for all periods presented. See Note 2 for additional information. Amounts Attributable to Controlling Interests For the years ended December 31, 2019 , 2018 and 2017 , the Income (Loss) From Discontinued Operations, net of tax on Duke Energy's Consolidated Statements of Operations is entirely attributable to controlling interest. Noncontrolling Interest Duke Energy maintains a controlling financial interest in certain less-than wholly owned non-regulated subsidiaries. As a result, Duke Energy consolidates these subsidiaries and presents the third-party investors' portion of Duke Energy's net income (loss), net assets and comprehensive income (loss) as noncontrolling interest. Noncontrolling interest is included as a component of equity on the Consolidated Balance Sheet. Several operating agreements of Duke Energy's subsidiaries with noncontrolling interest are subject to allocations of tax attributes and cash flows in accordance with contractual agreements that vary throughout the lives of the subsidiaries. Therefore, Duke Energy and the other investors' (the owners) interests in the subsidiaries are not fixed, and the subsidiaries apply the HLBV method in allocating income or loss and other comprehensive income or loss (all measured on a pretax basis) to the owners. The HLBV method measures the amounts that each owner would hypothetically claim at each balance sheet reporting date, including tax benefits realized by the owners, upon a hypothetical liquidation of the subsidiary at the net book value of its underlying assets. The change in the amount that each owner would hypothetically receive at the reporting date compared to the amount it would have received on the previous reporting date represents the amount of income or loss allocated to each owner for the reporting period. During 2019, Duke Energy received $428 million for the sale of noncontrolling interests to tax equity members subject to the HLBV method for projects totaling 718 MW in nameplate capacity. Duke Energy allocated approximately $165 million of losses to noncontrolling tax equity members utilizing the HLBV method for the year ended December 31, 2019 . Other operating agreements of Duke Energy's subsidiaries with noncontrolling interest allocate profit and loss based on their pro rata shares of the ownership interest in the respective subsidiary. Therefore, Duke Energy allocates net income or loss and other comprehensive income or loss of these subsidiaries to the owners based on their pro rata shares. During the third quarter of 2019, Duke Energy completed a sale of minority interest in a portion of certain renewable assets to John Hancock. John Hancock's ownership interest in the assets represents a noncontrolling interest. See Note 2 for additional information on the sale. Significant Accounting Policies Use of Estimates In preparing financial statements that conform to GAAP, the Duke Energy Registrants must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. Regulatory Accounting The majority of the Duke Energy Registrants’ operations are subject to price regulation for the sale of electricity and natural gas by state utility commissions or FERC. When prices are set on the basis of specific costs of the regulated operations and an effective franchise is in place such that sufficient natural gas or electric services can be sold to recover those costs, the Duke Energy Registrants apply regulatory accounting. Regulatory accounting changes the timing of the recognition of costs or revenues relative to a company that does not apply regulatory accounting. As a result, regulatory assets and regulatory liabilities are recognized on the Consolidated Balance Sheets. Regulatory assets and liabilities are amortized consistent with the treatment of the related cost in the ratemaking process. See Note 4 for further information. Regulatory accounting rules also require recognition of a disallowance (also called "impairment") loss if it becomes probable that part of the cost of a plant under construction (or a recently completed plant or an abandoned plant) will be disallowed for ratemaking purposes and a reasonable estimate of the amount of the disallowance can be made. For example, if a cost cap is set for a plant still under construction, the amount of the disallowance is a result of a judgment as to the ultimate cost of the plant. These disallowances can require judgments on allowed future rate recovery. When it becomes probable that regulated generation, transmission or distribution assets will be abandoned, the cost of the asset is removed from plant in service. The value that may be retained as a regulatory asset on the balance sheet for the abandoned property is dependent upon amounts that may be recovered through regulated rates, including any return. As such, an impairment charge could be partially or fully offset by the establishment of a regulatory asset if rate recovery is probable. The impairment charge for a disallowance of costs for regulated plants under construction, recently completed or abandoned is based on discounted cash flows. The Duke Energy Registrants utilize cost-tracking mechanisms, commonly referred to as fuel adjustment clauses or PGA clauses. These clauses allow for the recovery of fuel and fuel-related costs, portions of purchased power, natural gas costs and hedging costs through surcharges on customer rates. The difference between the costs incurred and the surcharge revenues is recorded either as an adjustment to Operating Revenues, Operating Expenses – Fuel used in electric generation or Operating Expenses – Cost of natural gas on the Consolidated Statements of Operations, with an off-setting impact on regulatory assets or liabilities. Cash, Cash Equivalents and Restricted Cash All highly liquid investments with maturities of three months or less at the date of acquisition are considered cash equivalents. Duke Energy, Progress Energy and Duke Energy Florida have restricted cash balances related primarily to collateral assets, escrow deposits and VIEs. See Note 18 for additional information. Restricted cash amounts are included in Other within Current Assets and Other Noncurrent Assets on the Consolidated Balance Sheets. The following table presents the components of cash, cash equivalents and restricted cash included in the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 311 $ 48 $ 17 $ 442 $ 67 $ 36 Other 222 39 39 141 39 39 Other Noncurrent Assets Other 40 39 — 8 6 — Total cash, cash equivalents and restricted cash $ 573 $ 126 $ 56 $ 591 $ 112 $ 75 Inventory Inventory related to regulated operations is valued at historical cost. Inventory related to nonregulated operations is valued at the lower of cost or market. Inventory is charged to expense or capitalized to property, plant and equipment when issued, primarily using the average cost method. Excess or obsolete inventory is written-down to the lower of cost or net realizable value. Once inventory has been written-down, it creates a new cost basis for the inventory that is not subsequently written-up. Provisions for inventory write-offs were not material at December 31, 2019 , and 2018 , respectively. The components of inventory are presented in the tables below. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,297 $ 768 $ 1,038 $ 686 $ 351 $ 79 $ 318 $ 5 Coal 586 187 186 138 48 15 198 — Natural gas, oil and other 349 41 199 110 90 41 1 67 Total inventory $ 3,232 $ 996 $ 1,423 $ 934 $ 489 $ 135 $ 517 $ 72 December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,238 $ 731 $ 1,049 $ 734 $ 315 $ 84 $ 312 $ 2 Coal 491 175 192 106 86 14 109 — Natural gas, oil and other 355 42 218 114 103 28 1 68 Total inventory $ 3,084 $ 948 $ 1,459 $ 954 $ 504 $ 126 $ 422 $ 70 Investments in Debt and Equity Securities The Duke Energy Registrants classify investments in equity securities as FV-NI and investments in debt securities as AFS. Both categories are recorded at fair value on the Consolidated Balance Sheets. Realized and unrealized gains and losses on securities classified as FV-NI are reported through net income. Unrealized gains and losses for debt securities classified as AFS are included in AOCI until realized, except OTTIs that are included in earnings immediately. At the time gains and losses for debt securities are realized, they are reported through net income. For certain investments of regulated operations, such as substantially all of the NDTF, realized and unrealized gains and losses (including any OTTIs) on debt securities are recorded as a regulatory asset or liability. The credit loss portion of debt securities of nonregulated operations are included in earnings. Investments in debt and equity securities are classified as either current or noncurrent based on management’s intent and ability to sell these securities, taking into consideration current market liquidity. See Note 16 for further information. Goodwill Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont perform annual goodwill impairment tests as of August 31 each year at the reporting unit level, which is determined to be a business segment or one level below. Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont update these tests between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. See Note 12 for further information. Intangible Assets Intangible assets are included in Other in Other Noncurrent Assets on the Consolidated Balance Sheets. Generally, intangible assets are amortized using an amortization method that reflects the pattern in which the economic benefits of the intangible asset are consumed or on a straight-line basis if that pattern is not readily determinable. Amortization of intangibles is reflected in Depreciation and amortization on the Consolidated Statements of Operations. Intangible assets are subject to impairment testing and if impaired, the carrying value is accordingly reduced. Emission allowances permit the holder of the allowance to emit certain gaseous byproducts of fossil fuel combustion, including SO 2 and NO X . Allowances are issued by the EPA at zero cost and may also be bought and sold via third-party transactions. Allowances allocated to or acquired by the Duke Energy Registrants are held primarily for consumption. Carrying amounts for emission allowances are based on the cost to acquire the allowances. Emission allowances are expensed to Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. RECs are used to measure compliance with renewable energy standards and are held primarily for consumption. See Note 12 for further information. Long-Lived Asset Impairments The Duke Energy Registrants evaluate long-lived assets, excluding goodwill, for impairment when circumstances indicate the carrying value of those assets may not be recoverable. An impairment exists when a long-lived asset’s carrying value exceeds the estimated undiscounted cash flows expected to result from the use and eventual disposition of the asset. The estimated cash flows may be based on alternative expected outcomes that are probability weighted. If the carrying value of the long-lived asset is not recoverable based on these estimated future undiscounted cash flows, the carrying value of the asset is written-down to its then-current estimated fair value and an impairment charge is recognized. The Duke Energy Registrants assess fair value of long-lived assets using various methods, including recent comparable third-party sales, internally developed discounted cash flow analysis and analysis from outside advisors. Triggering events to reassess cash flows may include, but are not limited to, significant changes in commodity prices, the condition of an asset or management’s interest in selling the asset. Equity Method Investment Impairments Investments in affiliates that are not controlled by Duke Energy, but over which it has significant influence, are accounted for using the equity method. Equity method investments are assessed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable. If the decline in value is considered to be other than temporary, the investment is written down to its estimated fair value, which establishes a new cost basis in the investment. Impairment assessments use a discounted cash flow income approach and include consideration of the severity and duration of any decline in the fair value of the investments. The estimated cash flows may be based on alternative expected outcomes that are probability weighted. Key inputs that involve estimates and significant management judgment include cash flow projections, selection of a discount rate, probability weighting of potential outcomes, and whether any decline in value is considered temporary. Property, Plant and Equipment Property, plant and equipment are stated at the lower of depreciated historical cost net of any disallowances or fair value, if impaired. The Duke Energy Registrants capitalize all construction-related direct labor and material costs, as well as indirect construction costs such as general engineering, taxes and financing costs. See “Allowance for Funds Used During Construction and Interest Capitalized” for information on capitalized financing costs. Costs of renewals and betterments that extend the useful life of property, plant and equipment are also capitalized. The cost of repairs, replacements and major maintenance projects, which do not extend the useful life or increase the expected output of the asset, are expensed as incurred. Depreciation is generally computed over the estimated useful life of the asset using the composite straight-line method. Depreciation studies are conducted periodically to update composite rates and are approved by state utility commissions and/or the FERC when required. The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2019 2018 2017 Duke Energy 3.1 % 3.0 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.8 % Progress Energy 3.1 % 2.9 % 2.6 % Duke Energy Progress 3.1 % 2.9 % 2.6 % Duke Energy Florida 3.1 % 3.0 % 2.8 % Duke Energy Ohio 2.6 % 2.8 % 2.8 % Duke Energy Indiana 3.3 % 3.3 % 3.0 % Piedmont 2.4 % 2.5 % 2.3 % In general, when the Duke Energy Registrants retire regulated property, plant and equipment, the original cost plus the cost of retirement, less salvage value and any depreciation already recognized, is charged to accumulated depreciation. However, when it becomes probable the asset will be retired substantially in advance of its original expected useful life or is abandoned, the cost of the asset and the corresponding accumulated depreciation is recognized as a separate asset. If the asset is still in operation, the net amount is classified as Generation facilities to be retired, net on the Consolidated Balance Sheets. If the asset is no longer operating, the net amount is classified in Regulatory assets on the Consolidated Balance Sheets if deemed recoverable (see discussion of long-lived asset impairments above). The carrying value of the asset is based on historical cost if the Duke Energy Registrants are allowed to recover the remaining net book value and a return equal to at least the incremental borrowing rate. If not, an impairment is recognized to the extent the net book value of the asset exceeds the present value of future revenues discounted at the incremental borrowing rate. When the Duke Energy Registrants sell entire regulated operating units, or retire or sell nonregulated properties, the original cost and accumulated depreciation and amortization balances are removed from Property, Plant and Equipment on the Consolidated Balance Sheets. Any gain or loss is recorded in earnings, unless otherwise required by the applicable regulatory body. See Note 11 for additional information. Nuclear Fuel Nuclear fuel is classified as Property, Plant and Equipment on the Consolidated Balance Sheets. Nuclear fuel in the front-end fuel processing phase is considered work in progress and not amortized until placed in service. Amortization of nuclear fuel is included within Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Amortization is recorded using the units-of-production method. Allowance for Funds Used During Construction and Interest Capitalized For regulated operations, the debt and equity costs of financing the construction of property, plant and equipment are reflected as AFUDC and capitalized as a component of the cost of property, plant and equipment. AFUDC equity is reported on the Consolidated Statements of Operations as non-cash income in Other income and expenses, net. AFUDC debt is reported as a non-cash offset to Interest Expense. After construction is completed, the Duke Energy Registrants are permitted to recover these costs through their inclusion in rate base and the corresponding subsequent depreciation or amortization of those regulated assets. AFUDC equity, a permanent difference for income taxes, reduces the ETR when capitalized and increases the ETR when depreciated or amortized. See Note 24 for additional information. For nonregulated operations, interest is capitalized during the construction phase with an offsetting non-cash credit to Interest Expense on the Consolidated Statements of Operations. Asset Retirement Obligations AROs are recognized for legal obligations associated with the retirement of property, plant and equipment. Substantially all AROs are related to regulated operations. When recording an ARO, the present value of the projected liability is recognized in the period in which it is incurred, if a reasonable estimate of fair value can be made. The liability is accreted over time. For operating plants, the present value of the liability is added to the cost of the associated asset and depreciated over the remaining life of the asset. For retired plants, the present value of the liability is recorded as a regulatory asset unless determined not to be probable of recovery. The present value of the initial obligation and subsequent updates are based on discounted cash flows, which include estimates regarding timing of future cash flows, selection of discount rates and cost escalation rates, among other factors. These estimates are subject to change. Depreciation expense is adjusted prospectively for any changes to the carrying amount of the associated asset. The Duke Energy Registrants receive amounts to fund the cost of the ARO for regulated operations through a combination of regulated revenues and earnings on the NDTF. As a result, amounts recovered in regulated revenues, earnings on the NDTF, accretion expense and depreciation of the associated asset are netted and deferred as a regulatory asset or liability. Obligations for nuclear decommissioning are based on site-specific cost studies. Duke Energy Carolinas and Duke Energy Progress assume prompt dismantlement of the nuclear facilities after operations are ceased. In 2019, Duke Energy Florida entered into an agreement for the accelerated decommissioning of Crystal River Unit 3. See Note 4 for more information. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida also assume that spent fuel will be stored on-site until such time that it can be transferred to a yet to be built DOE facility. Obligations for closure of ash basins are based upon discounted cash flows of estimated costs for site-specific plans, if known, or probability weightings of the potential closure methods if the closure plans are under development and multiple closure options are being considered and evaluated on a site-by-site basis. See Note 10 for additional information. Revenue Recognition Duke Energy recognizes revenue as customers obtain control of promised goods and services in an amount that reflects consideration expected in exchange for those goods or services. Generally, the delivery of electricity and natural gas results in the transfer of control to customers at the time the commodity is delivered and the amount of revenue recognized is equal to the amount billed to each customer, including estimated volumes delivered when billings have not yet occurred. See Note 19 for further information. Derivatives and Hedging Derivative and non-derivative instruments may be used in connection with commodity price and interest rate activities, including swaps, futures, forwards and options. All derivative instruments, except those that qualify for the NPNS exception, are recorded on the Consolidated Balance Sheets at fair value. Qualifying derivative instruments may be designated as either cash flow hedges or fair value hedges. Other derivative instruments (undesignated contracts) either have not been designated or do not qualify as hedges. The effective portion of the change in the fair value of cash flow hedges is recorded in AOCI. The effective portion of the change in the fair value of a fair value hedge is offset in net income by changes in the hedged item. For activity subject to regulatory accounting, gains and losses on derivative contracts are reflected as regulatory assets or liabilities and not as other comprehensive income or current period income. As a result, changes in fair value of these derivatives have no immediate earnings impact. Formal documentation, including transaction type and risk management strategy, is maintained for all contracts accounted for as a hedge. At inception and at least every three months thereafter, the hedge contract is assessed to see if it is highly effective in offsetting changes in cash flows or fair values of hedged items. See Note 15 for further information. Captive Insurance Reserves Duke Energy has captive insurance subsidiaries that provide coverage, on an indemnity basis, to the Subsidiary Registrants as well as certain third parties, on a limited basis, for financial losses, primarily related to property, workers’ compensation and general liability. Liabilities include provisions for estimated losses incurred but not reported (IBNR), as well as estimated provisions for known claims. IBNR reserve estimates are primarily based upon historical loss experience, industry data and other actuarial assumptions. Reserve estimates are adjusted in future periods as actual losses differ from experience. Duke Energy, through its captive insurance entities, also has reinsurance coverage with third parties for certain losses above a per occurrence and/or aggregate retention. Receivables for reinsurance coverage are recognized when realization is deemed probable. Unamortized Debt Premium, Discount and Expense Premiums, discounts and expenses incurred with the issuance of outstanding long-term debt are amortized over the term of the debt issue. The gain or loss on extinguishment associated with refinancing higher-cost debt obligations in the regulated operations is amortized over the remaining life of the original instrument. Amortization expense is recorded as Interest Expense in the Consolidated Statements of Operations and is reflected as Depreciation, amortization and accretion within Net cash provided by operating activities on the Consolidated Statements of Cash Flows. Premiums, discounts and expenses are presented as an adjustment to the carrying value of the debt amount and included in Long-Term Debt on the Consolidated Balance Sheets presented. Preferred Stock Preferred stock is reviewed to determine the appropriate balance sheet classification and embedded features, such as call options, are evaluated to determine if they should be bifurcated and accounted for separately. Costs directly related to the issuance of preferred stock is recorded as a reduction of the proceeds received. The liability for the dividend is recognized when declared. The accumulated dividends on the cumulative preferred stock is recognized to net income available to Duke Energy Corporation in the EPS calculation. See Note 20 for further information. Loss Contingencies and Environmental Liabilities Contingent losses are recorded when it is probable a loss has occurred and can be reasonably estimated. When a range of the probable loss exists and no amount within the range is a better estimate than any other amount, the minimum amount in the range is recorded. Unless otherwise required by GAAP, legal fees are expensed as incurred. Environmental liabilities are recorded on an undiscounted basis when environmental remediation or other liabilities become probable and can be reasonably estimated. Environmental expenditures related to past operations that do not generate current or future revenues are expensed. Environmental expenditures related to operations that generate current or future revenues are expensed or capitalized, as appropriate. Certain environmental expenditures receive regulatory accounting treatment and are recorded as regulatory assets. See Notes 4 and 5 for further information. Pension and Other Post-Retirement Benefit Plans Duke Energy maintains qualified, non-qualified and other post-retirement benefit plans. Eligible employees of the Subsidiary Registrants participate in the respective qualified, non-qualified and other post-retirement benefit plans and the Subsidiary Registrants are allocated their proportionate share of benefit costs. See Note 23 for further information, including significant accounting policies associated with these plans

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONS ACQUISITIONS The Duke Energy Registrants consolidate assets and liabilities from acquisitions as of the purchase date and include earnings from acquisitions in consolidated earnings after the purchase date. 2016 Acquisition of Piedmont Natural Gas On October 3, 2016, Duke Energy acquired all outstanding common stock of Piedmont for a total cash purchase price of $5 billion and assumed Piedmont's existing long-term debt, which had a fair value of approximately $2 billion at the time of the acquisition. The acquisition provides a foundation for Duke Energy to establish a broader, long-term strategic natural gas infrastructure platform to complement its existing natural gas pipeline investments and regulated natural gas business in the Midwest. In connection with the closing of the acquisition, Piedmont became a wholly owned subsidiary of Duke Energy. Accounting Charges Related to the Acquisition Duke Energy incurred pretax transaction and integration costs associated with the acquisition of $84 million and $103 million for the years ended December 31, 2018, and 2017, respectively. Amounts recorded on the Consolidated Statements of Operations in 2018 and 2017 were primarily system integration costs of $78 million and $71 million , respectively, related to combining the various operational and financial systems of Duke Energy and Piedmont, including a one-time software impairment resulting from planned accounting system and process integration in 2017. A $7 million charge was recorded within Impairment Charges, with the remaining $64 million recorded within Operation, maintenance and other in 2017. The majority of transition and integration activities were completed by the end of 2018. DISPOSITIONS On April 24, 2019, Duke Energy executed an agreement to sell a minority interest in a portion of certain renewable assets within the Commercial Renewables segment. The sale closed on September 6, 2019, and resulted in pretax proceeds to Duke Energy of $415 million . The portion of Duke Energy’s commercial renewables energy portfolio sold includes 49% of 37 operating wind, solar and battery storage assets and 33% of 11 operating solar assets across the U.S. Duke Energy retained control of these assets, and, therefore, no gain or loss was recognized on the Consolidated Statements of Operations. The difference between the consideration received and the carrying value of the noncontrolling interest claim on net assets is $466 million , net of a tax benefit of $8 million , and was recorded in equity.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Reportable segments are determined based on information used by the chief operating decision-maker in deciding how to allocate resources and evaluate the performance of the business. Duke Energy evaluates segment performance based on segment income. Segment income is defined as income from continuing operations net of income attributable to noncontrolling interests. Segment income, as discussed below, includes intercompany revenues and expenses that are eliminated on the Consolidated Financial Statements. Certain governance costs are allocated to each segment. In addition, direct interest expense and income taxes are included in segment income. Products and services are sold between affiliate companies and reportable segments of Duke Energy at cost. Segment assets as presented in the tables that follow exclude all intercompany assets. Duke Energy Duke Energy's segment structure includes the following segments: Electric Utilities and Infrastructure, Gas Utilities and Infrastructure and Commercial Renewables. The Electric Utilities and Infrastructure segment includes Duke Energy's regulated electric utilities in the Carolinas, Florida and the Midwest. The regulated electric utilities conduct operations through the Subsidiary Registrants that are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. Electric Utilities and Infrastructure also includes Duke Energy's electric transmission infrastructure investments. The Gas Utilities and Infrastructure segment includes Piedmont, Duke Energy's natural gas local distribution companies in Ohio and Kentucky, and Duke Energy's natural gas storage and midstream pipeline investments. Gas Utilities and Infrastructure's operations are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. The Commercial Renewables segment is primarily comprised of nonregulated utility-scale wind and solar generation assets located throughout the U.S. On April 24, 2019, Duke Energy executed an agreement to sell a minority interest in a portion of certain renewable assets. See Note 2 for additional information on the minority interest sale. The remainder of Duke Energy’s operations is presented as Other, which is primarily comprised of interest expense on holding company debt, unallocated corporate costs and Duke Energy’s wholly owned captive insurance company, Bison. Other also includes Duke Energy's interest in NMC. See Note 13 for additional information on the investment in NMC. Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Year Ended December 31, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 22,798 $ 1,770 $ 487 $ 25,055 $ 24 $ — $ 25,079 Intersegment Revenues 33 96 — 129 71 (200 ) — Total Revenues $ 22,831 $ 1,866 $ 487 $ 25,184 $ 95 $ (200 ) $ 25,079 Interest Expense $ 1,345 $ 117 $ 95 $ 1,557 $ 705 $ (58 ) $ 2,204 Depreciation and amortization 3,951 256 168 4,375 178 (5 ) 4,548 Equity in earnings (losses) of unconsolidated affiliates 9 114 (4 ) 119 43 — 162 Income tax expense (benefit) 785 22 (115 ) 692 (173 ) — 519 Segment income (loss) (a)(b) 3,536 432 198 4,166 (452 ) — 3,714 Add back noncontrolling interest (c) (177 ) Add back preferred stock dividend 41 Loss from discontinued operations, net of tax (7 ) Net income $ 3,571 Capital investments expenditures and acquisitions $ 8,263 $ 1,539 $ 1,423 $ 11,225 $ 221 $ — $ 11,446 Segment assets 135,561 13,921 6,020 155,502 3,148 188 158,838 (a) Electric Utilities and Infrastructure includes a $27 million reduction of a prior year impairment at Citrus County CC related to the plant's cost cap. See Note 4 for additional information. (b) Gas Utilities and Infrastructure includes an after-tax impairment charge of $19 million for the remaining investment in Constitution. See Note 13 for additional information. (c) Includes the allocation of losses to noncontrolling tax equity members. See Note 1 for additional information. Year Ended December 31, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 22,242 $ 1,783 $ 477 $ 24,502 $ 19 $ — $ 24,521 Intersegment Revenues 31 98 — 129 70 (199 ) — Total Revenues $ 22,273 $ 1,881 $ 477 $ 24,631 $ 89 $ (199 ) $ 24,521 Interest Expense $ 1,288 $ 106 $ 88 $ 1,482 $ 657 $ (45 ) $ 2,094 Depreciation and amortization 3,523 245 155 3,923 152 (1 ) 4,074 Equity in earnings (losses) of unconsolidated affiliates 5 27 (1 ) 31 52 — 83 Income tax expense (benefit) (a) 799 78 (147 ) 730 (282 ) — 448 Segment income (loss) (b)(c)(d)(e) 3,058 274 9 3,341 (694 ) — 2,647 Add back noncontrolling interest component (22 ) Loss from discontinued operations, net of tax 19 Net income $ 2,644 Capital investments expenditures and acquisitions $ 8,086 $ 1,133 $ 193 $ 9,412 $ 256 $ — $ 9,668 Segment assets 125,364 12,361 4,204 141,929 3,275 188 145,392 (a) All segments include adjustments to the December 31, 2017, estimate of the income tax effects of the Tax Act. Electric Utilities and Infrastructure includes a $24 million expense, Gas Utilities and Infrastructure includes a $1 million expense, Commercial Renewables includes a $3 million benefit and Other includes a $2 million benefit. See Note 24 for additional information. (b) Electric Utilities and Infrastructure includes after-tax regulatory and legislative impairment charges of $202 million related to rate case orders, settlements or other actions of regulators or legislative bodies and an after-tax impairment charge of $46 million related to the Citrus County CC at Duke Energy Florida. See Note 4 for additional information. (c) Gas Utilities and Infrastructure includes an after-tax impairment charge of $42 million for the investment in Constitution. See Note 13 for additional information. (d) Commercial Renewables includes an impairment charge of $91 million , net of $2 million Noncontrolling interests, related to goodwill. See Note 12 for additional information. (e) Other includes $65 million of after-tax costs to achieve the Piedmont merger, $144 million of after-tax severance charges related to a companywide initiative and an $82 million after-tax loss on the sale of Beckjord described below. For additional information, see Note 2 for the Piedmont Merger and Note 21 for severance charges. In February 2018, Duke Energy sold Beckjord, a nonregulated facility retired during 2014, and recorded a pretax loss of $106 million within (Losses) Gains on Sales of Other Assets and Other, net and $1 million within Operation, maintenance and other on Duke Energy's Consolidated Statements of Operations for the year ended December 31, 2018. The sale included the transfer of coal ash basins and other real property and indemnification from any and all potential future claims related to the property, whether arising under environmental laws or otherwise. Year Ended December 31, 2017 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,300 $ 1,743 $ 460 $ 23,503 $ 62 $ — $ 23,565 Intersegment Revenues 31 93 — 124 76 (200 ) — Total Revenues $ 21,331 $ 1,836 $ 460 $ 23,627 $ 138 $ (200 ) $ 23,565 Interest Expense $ 1,240 $ 105 $ 87 $ 1,432 $ 574 $ (20 ) $ 1,986 Depreciation and amortization 3,010 231 155 3,396 131 — 3,527 Equity in earnings (losses) of unconsolidated affiliates 5 62 (5 ) 62 57 — 119 Income tax expense (benefit) (a) 1,355 116 (628 ) 843 353 — 1,196 Segment income (loss) (b)(c)(d) 3,210 319 441 3,970 (905 ) — 3,065 Add back noncontrolling interest component 5 Loss from discontinued operations, net of tax (6 ) Net income $ 3,064 Capital investments expenditures and acquisitions $ 7,024 $ 907 $ 92 $ 8,023 $ 175 $ — $ 8,198 Segment assets 119,423 11,462 4,156 135,041 2,685 188 137,914 (a) All segments include impacts of the Tax Act. Electric Utilities and Infrastructure includes a $231 million benefit, Gas Utilities and Infrastructure includes a $26 million benefit, Commercial Renewables includes a $442 million benefit and Other includes charges of $597 million . (b) Electric Utilities and Infrastructure includes after-tax regulatory settlement charges of $98 million . (c) Commercial Renewables includes after-tax impairment charges of $74 million related to certain wind projects and the Energy Management Solutions reporting unit. See Notes 11 and 12 for additional information. (d) Other includes $64 million of after-tax costs to achieve the Piedmont merger. See Note 2 for additional information. Geographical Information Substantially all assets and revenues from continuing operations are within the U.S. Major Customers For the year ended December 31, 2019 , revenues from one customer of Duke Energy Progress are $635 million . Duke Energy Progress has one reportable segment, Electric Utilities and Infrastructure. No other Subsidiary Registrant has an individual customer representing more than 10% of its revenues. Products and Services The following table summarizes revenues of the reportable segments by type. Retail Wholesale Retail Total (in millions) Electric Electric Natural Gas Other Revenues 2019 Electric Utilities and Infrastructure $ 19,745 $ 2,231 $ — $ 855 $ 22,831 Gas Utilities and Infrastructure — — 1,782 84 1,866 Commercial Renewables — 389 — 98 487 Total Reportable Segments $ 19,745 $ 2,620 $ 1,782 $ 1,037 $ 25,184 2018 Electric Utilities and Infrastructure $ 19,013 $ 2,345 $ — $ 915 $ 22,273 Gas Utilities and Infrastructure — — 1,817 64 1,881 Commercial Renewables — 375 — 102 477 Total Reportable Segments $ 19,013 $ 2,720 $ 1,817 $ 1,081 $ 24,631 2017 Electric Utilities and Infrastructure $ 18,177 $ 2,104 $ — $ 1,050 $ 21,331 Gas Utilities and Infrastructure — — 1,732 104 1,836 Commercial Renewables — 375 — 85 460 Total Reportable Segments $ 18,177 $ 2,479 $ 1,732 $ 1,239 $ 23,627 Duke Energy Ohio Duke Energy Ohio has two reportable segments, Electric Utilities and Infrastructure and Gas Utilities and Infrastructure. Electric Utilities and Infrastructure transmits and distributes electricity in portions of Ohio and generates, distributes and sells electricity in portions of Northern Kentucky. Gas Utilities and Infrastructure transports and sells natural gas in portions of Ohio and Northern Kentucky. Both reportable segments conduct operations primarily through Duke Energy Ohio and its wholly owned subsidiary, Duke Energy Kentucky. The remainder of Duke Energy Ohio's operations is presented as Other. In December 2018, the PUCO approved an order which allows the recovery or credit of revenues and expenses related to Duke Energy Ohio's contractual arrangement to buy power from OVEC power plants. Due to the change in regulatory treatment of these amounts, OVEC revenues and expenses are now reflected in the Electric Utilities and Infrastructure segment. Previously, OVEC revenues and expense were included in Other. These amounts are deemed immaterial for Duke Energy Ohio. Therefore, no prior period amounts were restated. See Note 4 for additional information on the PUCO order. All Duke Energy Ohio assets and revenues from continuing operations are within the U.S. Year Ended December 31, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,456 $ 484 $ 1,940 $ — $ — $ 1,940 Interest expense $ 80 $ 29 $ 109 $ — $ — $ 109 Depreciation and amortization 182 83 265 — — 265 Income tax expense (benefit) 20 21 41 (1 ) — 40 Segment income (loss)/Net income 159 85 244 (5 ) — 239 Loss from discontinued operations, net of tax (1 ) Net income $ 238 Capital expenditures $ 680 $ 272 $ 952 $ — $ — $ 952 Segment assets 6,188 3,116 9,304 34 — 9,338 Year Ended December 31, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,450 $ 506 $ 1,956 $ 1 $ — $ 1,957 Interest expense $ 67 $ 24 $ 91 $ 1 $ — $ 92 Depreciation and amortization 183 85 268 — — 268 Income tax expense (benefit) 47 24 71 (28 ) — 43 Segment income (loss)/Net income (a) 186 93 279 (103 ) — 176 Capital expenditures $ 655 $ 172 $ 827 $ — $ — $ 827 Segment assets 5,643 2,874 8,517 38 — 8,555 (a) Other includes the loss on the sale of Beckjord, see discussion above. Year Ended December 31, 2017 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,373 $ 508 $ 1,881 $ 42 $ — $ 1,923 Interest expense $ 62 $ 28 $ 90 $ 1 $ — $ 91 Depreciation and amortization 178 83 261 — — 261 Income tax expense (benefit) 40 39 79 (20 ) — 59 Segment income (loss) 138 85 223 (30 ) — 193 Loss from discontinued operations, net of tax (1 ) Net income $ 192 Capital expenditures $ 491 $ 195 $ 686 $ — $ — $ 686 Segment assets 5,066 2,758 7,824 66 (15 ) 7,875

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2019
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS REGULATORY ASSETS AND LIABILITIES The Duke Energy Registrants record regulatory assets and liabilities that result from the ratemaking process. See Note 1 for further information. The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets of Duke Energy and Progress Energy. See separate tables below for balances by individual registrant. Duke Energy Progress Energy December 31, December 31, (in millions) 2019 2018 2019 2018 Regulatory Assets AROs – coal ash $ 4,084 $ 4,255 $ 1,843 $ 2,061 AROs – nuclear and other 739 772 668 601 Accrued pension and OPEB 2,391 2,654 897 1,074 Storm cost deferrals 1,399 1,117 1,214 953 Nuclear asset securitized balance, net 1,042 1,093 1,042 1,093 Debt fair value adjustment 1,019 1,099 — — Deferred fuel and purchased power 528 838 305 600 Deferred asset – Lee and Harris COLA 388 426 38 43 Hedge costs deferrals 356 204 129 74 Demand side management (DSM)/Energy Efficiency (EE) 343 449 241 256 Advanced metering infrastructure (AMI) 338 367 114 127 Retired generation facilities 331 402 266 324 Post-in-service carrying costs (PISCC) and deferred operating expenses 329 320 33 36 Vacation accrual 214 213 41 41 Derivatives – natural gas supply contracts 117 141 — — Nuclear deferral 107 133 40 46 Manufactured gas plant (MGP) 102 99 — — Deferred pipeline integrity costs 79 65 — — NCEMPA deferrals 72 50 72 50 East Bend deferrals 44 47 — — Transmission expansion obligation 36 39 — — Amounts due from customers 36 24 — — Grid modernization 28 31 — — Other 896 784 349 322 Total regulatory assets 15,018 15,622 7,292 7,701 Less: current portion 1,796 2,005 946 1,137 Total noncurrent regulatory assets $ 13,222 $ 13,617 $ 6,346 $ 6,564 Regulatory Liabilities Net regulatory liability related to income taxes $ 7,872 $ 8,058 $ 2,595 $ 2,710 Costs of removal 5,756 5,421 2,561 2,135 AROs – nuclear and other 1,100 538 — — Accrued pension and OPEB 176 301 — 149 Amounts to be refunded to customers 34 34 — — Deferred fuel and purchased power 1 16 1 16 Other 1,109 1,064 398 319 Total regulatory liabilities 16,048 15,432 5,555 5,329 Less: current portion 784 598 330 280 Total noncurrent regulatory liabilities $ 15,264 $ 14,834 $ 5,225 $ 5,049 Descriptions of regulatory assets and liabilities summarized in the tables above and below follow. See tables below for recovery and amortization periods at the separate registrants. AROs – coal ash. Represents deferred depreciation and accretion related to the legal obligation to close ash basins. The costs are deferred until recovery treatment has been determined. See Notes 1 and 10 for additional information. AROs – nuclear and other. Represents regulatory assets or liabilities, including deferred depreciation and accretion, related to legal obligations associated with the future retirement of property, plant and equipment, excluding amounts related to coal ash. The AROs relate primarily to decommissioning nuclear power facilities. The amounts also include certain deferred gains and losses on NDTF investments. See Notes 1 and 10 for additional information. Accrued pension and OPEB. Accrued pension and OPEB represent regulatory assets and liabilities related to each of the Duke Energy Registrants’ respective shares of unrecognized actuarial gains and losses and unrecognized prior service cost and credit attributable to Duke Energy’s pension plans and OPEB plans. The regulatory asset or liability is amortized with the recognition of actuarial gains and losses and prior service cost and credit to net periodic benefit costs for pension and OPEB plans. The accrued pension and OPEB regulatory assets are expected to be recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail. Storm cost deferrals. Represents deferred incremental costs incurred related to major weather-related events. Nuclear asset securitized balance, net. Represents the balance associated with Crystal River Unit 3 retirement approved for recovery by the FPSC on September 15, 2015, and the upfront financing costs securitized in 2016 with issuance of the associated bonds. The regulatory asset balance is net of the AFUDC equity portion. Debt fair value adjustment. Purchase accounting adjustments recorded to state the carrying value of Progress Energy and Piedmont at fair value in connection with the 2012 and 2016 mergers, respectively. Amount is amortized over the life of the related debt. Deferred fuel and purchased power. Represents certain energy-related costs that are recoverable or refundable as approved by the applicable regulatory body. Deferred asset – Lee and Harris COLA. Represents deferred costs incurred for the canceled Lee and Harris nuclear projects. Hedge costs and other deferrals. Amounts relate to unrealized gains and losses on derivatives recorded as a regulatory asset or liability, respectively, until the contracts are settled. DSM/EE. Deferred costs related to various DSM and EE programs recoverable through various mechanisms. AMI. Represents deferred costs related to the installation of AMI meters and remaining net book value of non-AMI meters to be replaced at Duke Energy Carolinas, net book value of existing meters at Duke Energy Florida , Duke Energy Progress and Duke Energy Ohio and expected future recovery of net book value of electromechanical meters that have been replaced with AMI meters at Duke Energy Indiana. Retired generation facilities. Represents amounts to be recovered for facilities that have been retired and are probable of recovery. Post-in-service carrying costs (PISCC) and deferred operating expenses. Represents deferred depreciation and operating expenses as well as carrying costs on the portion of capital expenditures placed in service but not yet reflected in retail rates as plant in service. Vacation accrual. Represents vacation entitlement, which is generally recovered in the following year. Derivatives – natural gas supply contracts . Represents costs for certain long-dated, fixed quantity forward gas supply contracts, which are recoverable through PGA clauses. Nuclear deferral. Includes amounts related to levelizing nuclear plant outage costs, which allows for the recognition of nuclear outage expenses over the refueling cycle rather than when the outage occurs, resulting in the deferral of operations and maintenance costs associated with refueling. MGP. Represents remediation costs incurred at former MGP sites and the deferral of costs to be incurred at Duke Energy Ohio's East End and West End sites. Deferred pipeline integrity costs. Represents pipeline integrity management costs in compliance with federal regulations recovered through a rider mechanism. NCEMPA deferrals. Represents retail allocated cost deferrals and returns associated with the additional ownership interest in assets acquired from NCEMPA in 2015. East Bend deferrals. Represents both deferred operating expenses and deferred depreciation as well as carrying costs on the portion of East Bend that was acquired from Dayton Power and Light and that had been previously operated as a jointly owned facility. Transmission expansion obligation. Represents transmission expansion obligations related to Duke Energy Ohio’s withdrawal from MISO. Amounts due from customers. Relates primarily to margin decoupling and IMR recovery mechanisms. Grid modernization. Amounts represent deferred depreciation and operating expenses as well as carrying costs on the portion of capital expenditures placed in service but not yet reflected in retail rates as plant in service. Net regulatory liability related to income taxes. Amounts for all registrants include regulatory liabilities related primarily to impacts from the Tax Act. See Note 24 for additional information. Amounts have no immediate impact on rate base as regulatory assets are offset by deferred tax liabilities. Costs of removal. Represents funds received from customers to cover the future removal of property, plant and equipment from retired or abandoned sites as property is retired. Also includes certain deferred gains on NDTF investments. Amounts to be refunded to customers. Represents required rate reductions to retail customers by the applicable regulatory body. RESTRICTIONS ON THE ABILITY OF CERTAIN SUBSIDIARIES TO MAKE DIVIDENDS, ADVANCES AND LOANS TO DUKE ENERGY As a condition to the approval of merger transactions, the NCUC, PSCSC, PUCO, KPSC and IURC imposed conditions on the ability of Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio, Duke Energy Kentucky, Duke Energy Indiana and Piedmont to transfer funds to Duke Energy through loans or advances, as well as restricted amounts available to pay dividends to Duke Energy. Certain subsidiaries may transfer funds to the Parent by obtaining approval of the respective state regulatory commissions. These conditions imposed restrictions on the ability of the public utility subsidiaries to pay cash dividends as discussed below. Duke Energy Progress and Duke Energy Florida also have restrictions imposed by their first mortgage bond indentures, which in certain circumstances, limit their ability to make cash dividends or distributions on common stock. Amounts restricted as a result of these provisions were not material at December 31, 2019 . Additionally, certain other subsidiaries of Duke Energy have restrictions on their ability to dividend, loan or advance funds to Duke Energy due to specific legal or regulatory restrictions, including, but not limited to, minimum working capital and tangible net worth requirements. The restrictions discussed below were not a material amount of Duke Energy's and Progress Energy's net assets at December 31, 2019 . Duke Energy Carolinas Duke Energy Carolinas must limit cumulative distributions subsequent to mergers to (i) the amount of retained earnings on the day prior to the closing of the mergers, plus (ii) any future earnings recorded. Duke Energy Progress Duke Energy Progress must limit cumulative distributions subsequent to the mergers between Duke Energy and Progress Energy and Duke Energy and Piedmont to (i) the amount of retained earnings on the day prior to the closing of the respective mergers, plus (ii) any future earnings recorded. Duke Energy Ohio Duke Energy Ohio will not declare and pay dividends out of capital or unearned surplus without the prior authorization of the PUCO. Duke Energy Ohio received FERC and PUCO approval to pay dividends from its equity accounts that are reflective of the amount that it would have in its retained earnings account had push-down accounting for the Cinergy merger not been applied to Duke Energy Ohio’s balance sheet. The conditions include a commitment from Duke Energy Ohio that equity, adjusted to remove the impacts of push-down accounting, will not fall below 30% of total capital. Duke Energy Kentucky is required to pay dividends solely out of retained earnings and to maintain a minimum of 35% equity in its capital structure. Duke Energy Indiana Duke Energy Indiana must limit cumulative distributions subsequent to the merger between Duke Energy and Cinergy to (i) the amount of retained earnings on the day prior to the closing of the merger, plus (ii) any future earnings recorded. In addition, Duke Energy Indiana will not declare and pay dividends out of capital or unearned surplus without prior authorization of the IURC. Piedmont Piedmont must limit cumulative distributions subsequent to the acquisition of Piedmont by Duke Energy to (i) the amount of retained earnings on the day prior to the closing of the merger, plus (ii) any future earnings recorded. RATE-RELATED INFORMATION The NCUC, PSCSC, FPSC, IURC, PUCO, TPUC and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service. The FERC also regulates certification and siting of new interstate natural gas pipeline projects. Duke Energy Carolinas and Duke Energy Progress Hurricane Florence, Hurricane Michael and Winter Storm Diego Deferral Filings On December 21, 2018, Duke Energy Carolinas and Duke Energy Progress filed with the NCUC petitions for approval to defer the incremental costs incurred in connection with the response to Hurricane Florence, Hurricane Michael and Winter Storm Diego to a regulatory asset for recovery in the next base rate case. The NCUC issued an order requesting comments on the deferral positions. On March 5, 2019, the North Carolina Public Staff (Public Staff) filed comments. On April 2, 2019, Duke Energy Carolinas and Duke Energy Progress filed reply comments, which included revised estimates of approximately $553 million in incremental operation and maintenance expenses ( $171 million and $382 million for Duke Energy Carolinas and Duke Energy Progress, respectively) and approximately $96 million in capital costs ( $20 million and $76 million for Duke Energy Carolinas and Duke Energy Progress, respectively). On September 30, 2019, Duke Energy Carolinas requested that the NCUC consolidate its pending deferral request with its general rate case filed on that date. On October 30, 2019, Duke Energy Progress requested that the NCUC consolidate its pending deferral request with its general rate case filed on that date. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of these matters. Duke Energy Progress filed a deferral request for these storms with the PSCSC on January 11, 2019, which also included a request for the continuation of prior deferrals requested for ice storms and Hurricane Matthew, and on January 30, 2019, the PSCSC issued a directive approving the deferral request, followed by an order issued on February 21, 2019. On March 15, 2019, Duke Energy Progress filed a request with FERC requesting permission to defer transmission-related storm costs that would be charged to wholesale transmission customers through Duke Energy Progress' Open Access Transmission Tariff (OATT) and to recover those costs from wholesale transmission customers over a three-year recovery period. FERC accepted the filing on May 14, 2019, which allows Duke Energy Progress to proceed with the proposed cost deferral and recovery. Duke Energy Carolinas Regulatory Assets and Liabilities The following tables present the regulatory assets and liabilities recorded on Duke Energy Carolinas' Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 1,696 $ 1,725 (i) (b) Accrued pension and OPEB 477 581 (j) Storm cost deferrals 178 160 Yes (b) Deferred fuel and purchased power 222 196 (f) 2021 Deferred asset – Lee COLA 350 383 (b) Hedge costs deferrals (c) 198 101 Yes 2041 DSM/EE 100 169 (h) (h) AMI 166 176 Yes (b) Retired generation facilities (c) 16 21 Yes 2023 PISCC (c) 33 34 Yes (b) Vacation accrual 80 78 (e) 2020 Nuclear deferral 67 87 2021 Other 327 266 (b) Total regulatory assets 3,910 3,977 Less: current portion 550 520 Total noncurrent regulatory assets $ 3,360 $ 3,457 Regulatory Liabilities (a) Net regulatory liability related to income taxes (d) $ 3,060 $ 3,082 (b) Costs of removal (c) 1,936 1,968 Yes (g) AROs – nuclear and other 1,100 538 (b) Accrued pension and OPEB 39 38 (j) Other 543 572 (b) Total regulatory liabilities 6,678 6,198 Less: current portion 255 199 Total noncurrent regulatory liabilities $ 6,423 $ 5,999 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Includes regulatory liabilities related to the change in the federal tax rate as a result of the Tax Act and the change in the North Carolina tax rate, both discussed in Note 24 . (e) Earns a return on outstanding balance in North Carolina. (f) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina. (g) Recovered over the life of the associated assets. (h) Includes incentives on DSM/EE investments and is recovered through an annual rider mechanism. (i) Earns a debt and equity return on coal ash expenditures for North Carolina and South Carolina retail customers as permitted by various regulatory orders. (j) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail. 2017 North Carolina Rate Case On August 25, 2017, Duke Energy Carolinas filed an application with the NCUC for a rate increase for retail customers of approximately $647 million , which represented an approximate 13.6% increase in annual base revenues. The request for rate increase was driven by capital investments subsequent to the previous base rate case, including the W.S. Lee CC, grid improvement projects, AMI, investments in customer service technologies, costs of complying with CCR regulations and the Coal Ash Act and recovery of costs related to licensing and development of the William States Lee III Nuclear Station. On February 28, 2018, Duke Energy Carolinas and the Public Staff filed an Agreement and Stipulation of Partial Settlement resolving certain portions of the proceeding. Terms of the settlement included a return on equity of 9.9% and a capital structure of 52% equity and 48% debt. As a result of the settlement, Duke Energy Carolinas recorded a pretax charge of approximately $4 million in the first quarter of 2018 to Operation, maintenance and other on the Consolidated Statements of Operations. On June 22, 2018, the NCUC issued an order approving the Stipulation of Partial Settlement and requiring a revenue reduction. As a result of the June 22, 2018, order, Duke Energy Carolinas recorded a pretax charge of approximately $150 million to Impairment charges and Operation, maintenance and other on the Consolidated Statements of Operations. The charge was primarily related to the denial of a return on the Lee Nuclear Project and the assessment of a $70 million management penalty by reducing the annual recovery of deferred coal ash costs by $14 million per year over a five-year recovery period. On July 27, 2018, NCUC approved Duke Energy Carolinas' compliance filing. As a result, revised customer rates were effective on August 1, 2018. On July 20, 2018, the North Carolina Attorney General filed a Notice of Appeal to the North Carolina Supreme Court from the June 22, 2018, Order Accepting Stipulation, Deciding Contested Issues and Requiring Revenue Reduction issued by the NCUC. The Attorney General contends the commission’s order should be reversed and remanded, as it is in excess of the commission’s statutory authority; affected by errors of law; unsupported by competent, material and substantial evidence in view of the entire record as submitted; and arbitrary or capricious. The Sierra Club, North Carolina Sustainable Energy Association, North Carolina Justice Center, North Carolina Housing Coalition, Natural Resource Defense Council and Southern Alliance for Clean Energy also filed Notices of Appeal to the North Carolina Supreme Court. On August 8, 2018, the Public Staff filed a Notice of Cross Appeal to the North Carolina Supreme Court, which contends the commission’s June 22, 2018, order should be reversed and remanded, as it is affected by errors of law, and is unsupported by substantial evidence with regard to the commission’s failure to consider substantial evidence of coal ash related environmental violations. On November 29, 2018, the North Carolina Attorney General's Office filed a motion with the North Carolina Supreme Court requesting the court consolidate the Duke Energy Carolinas and Duke Energy Progress appeals and enter an order adopting the parties’ proposed briefing schedule as set out in the filing. On November 29, 2018, the North Carolina Supreme Court adopted a schedule for briefing set forth in the motion to consolidate the Duke Energy Carolinas and Duke Energy Progress appeals. Appellant briefs were filed on April 26, 2019. The Appellee response briefs were filed on September 25, 2019. Oral arguments before the North Carolina Supreme Court are scheduled for March 11, 2020. Duke Energy Carolinas cannot predict the outcome of this matter. 2019 North Carolina Rate Case On September 30, 2019, Duke Energy Carolinas filed an application with the NCUC for a net rate increase for retail customers of approximately $291 million , which represents an approximate 6% increase in annual base revenues. The gross rate case revenue increase request is $445 million , which is offset by an EDIT rider of $154 million to return to customers North Carolina and federal EDIT resulting from recent reductions in corporate tax rates. The request for rate increase is driven by major capital investments subsequent to the previous base rate case, coal ash pond closure costs, accelerated coal plant depreciation and deferred 2018 storm costs. Duke Energy Carolinas requests rates be effective no later than August 1, 2020. The NCUC has established a procedural schedule with an evidentiary hearing to commence on March 23, 2020. Duke Energy Carolinas cannot predict the outcome of this matter. 2018 South Carolina Rate Case On November 8, 2018, Duke Energy Carolinas filed an application with the PSCSC for a rate increase for retail customers of approximately $168 million , which represents an approximate 10% increase in retail revenues. The request for rate increase was driven by capital investments and environmental compliance progress made by Duke Energy Carolinas since its previous rate case, including the further implementation of Duke Energy Carolinas’ generation modernization program, which consists of retiring, replacing and upgrading generation plants, investments in customer service technologies and continued investments in base work to maintain its transmission and distribution systems. The request included net tax benefits resulting from the Tax Act of $66 million to reflect the change in ongoing tax expense, primarily from the reduction in the federal income tax rate from 35% to 21%. The request also included $46 million to return EDIT resulting from the federal tax rate change and deferred revenues since January 2018 related to the change and benefits of $17 million from a reduction in North Carolina state income taxes allocable to South Carolina (EDIT Rider). Duke Energy Carolinas also requested approval of its proposed Grid Improvement Plan (GIP), adjustments to its Prepaid Advantage Program and a variety of accounting orders related to ongoing costs for environmental compliance, including recovery over a five -year period of $242 million of deferred coal ash related compliance costs, grid investments between rate changes, incremental depreciation expense, a result of new depreciation rates from the depreciation study approved in the 2017 North Carolina Rate Case above, and the balance of development costs associated with the cancellation of the Lee Nuclear Project. Finally, Duke Energy Carolinas sought approval to establish a reserve and accrual for end-of-life nuclear costs for nuclear fuel and materials and supplies. On March 8, 2019, the ORS moved to establish a new and separate hearing docket to review and consider the GIP proposed by Duke Energy Carolinas. Subsequently, on March 12, 2019, the ORS and Duke Energy Carolinas executed a Stipulation resolving the ORS’s motion. The Stipulation provided that costs incurred for the GIP after January 1, 2019, would be deferred with a return, subject to evaluation in a future rate proceeding. The Stipulation was approved by the PSCSC on June 19, 2019. On December 16, 2019, Duke Energy Carolinas and Duke Energy Progress filed a Joint Petition to Establish an Informational Docket for Review and Consideration of Grid Improvement Plans through which Duke Energy Carolinas and Duke Energy Progress would provide interested stakeholders information on the companies' grid activities. The PSCSC requested parties comment on procedural matters by January 31; accordingly, various groups filed comments, none of which opposed an informational docket. Duke Energy Carolinas cannot predict the outcome of this matter. After hearings in March 2019, the PSCSC issued an order on May 21, 2019, which included a return on equity of 9.5% and a capital structure of 53% equity and 47% debt. The order also included the following material components: • Approval of cancellation of the Lee Nuclear Project, with Duke Energy Carolinas maintaining the Combined Operating License; • Approval of recovery of $125 million (South Carolina retail portion) of Lee Nuclear Project development costs (including AFUDC through December 2017) over a 12 -year period, but denial of a return on the deferred balance of costs; • Approval of recovery of $96 million of coal ash costs over a five-year period with a return at Duke Energy Carolinas' WACC; • Denial of recovery of $115 million of certain coal ash costs deemed to be related to the Coal Ash Act and incremental to the federal CCR rule; • Approval of a $66 million decrease to base rates to reflect the change in ongoing tax expense, primarily the reduction in the federal income tax rate from 35% to 21%; • Approval of a $45 million decrease through the EDIT Rider to return EDIT resulting from the federal tax rate change and deferred revenues since January 2018 related to the change, to be returned in accordance with the Average Rate Assumption Method (ARAM) for protected EDIT, over a 20-year period for unprotected EDIT associated with Property, Plant and Equipment, over a five-year period for unprotected EDIT not associated with Property, Plant and Equipment and over a five-year period for the deferred revenues; and • Approval of a $17 million decrease through the EDIT Rider related to reductions in the North Carolina state income tax rate from 6.9% to 2.5% to be returned over a five-year period. As a result of the order, revised customer rates were effective June 1, 2019. On May 31, 2019, Duke Energy Carolinas filed a Petition for Rehearing or Reconsideration of that order contending substantial rights of Duke Energy Carolinas were prejudiced by unlawful, arbitrary and capricious rulings by the commission on certain issues presented in the proceeding. On June 19, 2019, the PSCSC issued a Directive denying Duke Energy Carolinas' request to rehear or reconsider the commission's rulings on certain issues presented in the proceeding including coal ash remediation and disposal costs, return on equity and the recovery of a return on deferred operation and maintenance expenses. An order detailing the commission's decision in the Directive was issued on October 18, 2019. Duke Energy Carolinas filed a notice of appeal on November 15, 2019, with the South Carolina Supreme Court. On November 20, 2019, the South Carolina Energy Users Committee filed a Notice of Appeal and the ORS filed a Notice of Cross Appeal with the South Carolina Supreme Court. On January 8, 2020, Duke Energy Carolinas and the ORS filed a joint motion to extend briefing schedule deadlines. Appellant briefs are due on March 2, 2020, and Appellee response briefs are due on May 15, 2020. On February 12, 2020, Duke Energy Carolinas and the ORS filed a joint motion to extend briefing deadlines by 30 days. Based on legal analysis and the filing of the appeal, Duke Energy Carolinas has not recorded an adjustment for its deferred coal ash costs. Duke Energy Carolinas cannot predict the outcome of this matter. FERC Formula Rate Matter On July 31, 2017, PMPA filed a complaint with FERC alleging that Duke Energy Carolinas misapplied the formula rate under the PPA between the parties by including in its rates amortization expense associated with regulatory assets and recorded in a certain account without FERC approval. On February 15, 2018, FERC issued an order ruling in favor of PMPA and ordered Duke Energy Carolinas to refund to PMPA all amounts improperly collected under the PPA. Duke Energy Carolinas has issued to PMPA and similarly situated wholesale customers refunds of approximately $25 million . FERC also set the matter for settlement and hearing. PMPA and other customers filed a protest to Duke Energy Carolinas' refund report claiming that the refunds are inadequate in that (1) Duke Energy Carolinas invoked the limitations periods in the contracts to limit the time period for which the refunds were paid and the customers disagree that this limitation applies, and (2) Duke Energy Carolinas refunded only amounts recovered through a certain account and the customers have asserted that the order applies to all regulatory assets. On July 3, 2018, FERC issued an order accepting Duke Energy Carolinas' refund report and ruling that these two claims are outside the scope of FERC's February order. The settlement agreements and revised formula rates for all parties to the proceeding were filed on December 28, 2018. On April 2, 2019, FERC issued an order approving the settlement agreement as filed. Since then, Duke Energy Carolinas has implemented the terms of the settlement in rates with all wholesale customers, including non-intervening customers. On July 25, 2019, Duke Energy Carolinas received FERC approval for the accounting treatment requested for certain assets included in the settlement agreements. This is the final approval needed from FERC and concludes this proceeding. Sale of Hydroelectric (Hydro) Plants In May 2018, Duke Energy Carolinas entered an agreement for the sale of five hydro plants with a combined 18.7 -MW generation capacity in the Western Carolinas region to Northbrook Energy. The completion of the transaction was subject to approval from FERC for the four FERC-licensed plants, as well as other state regulatory agencies and was contingent upon regulatory approval from the NCUC and PSCSC to defer the total estimated loss on the sale of approximately $40 million . On July 5, 2018, Duke Energy Carolinas filed with the NCUC for approval of the sale of the five hydro plants to Northbrook, to transfer the CPCNs for the four North Carolina hydro plants and to establish a regulatory asset for the North Carolina retail portion of the difference between sales proceeds and net book value. On June 5, 2019, the NCUC issued an order approving the transfer of the hydro plants from Duke Energy Carolinas to Northbrook, granting deferral accounting and denying the Public Staff's motion for reconsideration. On August 28, 2018, Duke Energy Carolinas filed with PSCSC an Application for Approval of Transfer and Sale of Hydroelectric Generation Facilities, Acceptance for Filing of a Power Purchase Agreement and an Accounting Order to Establish a Regulatory Asset. On September 10, 2018, the ORS provided a letter to the commission stating its position on the application and on September 18, 2018, Duke Energy Carolinas requested this matter be carried over to allow Duke Energy Carolinas time to discuss certain accounting issues with the ORS. At its June 26, 2019, agenda meeting, the PSCSC voted to approve the transfer and sale subject to the recommendation of the ORS that the issuance of an Accounting Order will not preclude the ORS, the commission or any other party from addressing the reasonableness of these costs, any return sought and including any carrying costs in the next rate case. On August 9, 2018, Duke Energy Carolinas and Northbrook filed a joint Application for Transfer of Licenses with the FERC. On December 27, 2018, the FERC issued its Order Approving Transfer of Licenses for the four FERC-licensed hydro plants. On January 18, 2019, Duke Energy Carolinas and Northbrook Carolina Hydro II, LLC requested a six-month extension of time to comply with the requirement of the December 27, 2018, order that Northbrook submit to FERC certified copies of all instruments of conveyance and signed acceptance sheets within 60 days of the date of the order. On February 14, 2019, FERC issued an order granting extensions until August 26, 2019, to comply with the requirements of the December 27, 2018, order. The closing occurred on August 16, 2019. A regulatory asset was established for approximately $32 million , which represents the total deferral amount for North Carolina and South Carolina retail. The North Carolina retail portion will be amortized pursuant to an order from the NCUC. Duke Energy Carol

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES INSURANCE General Insurance The Duke Energy Registrants have insurance and reinsurance coverage either directly or through indemnification from Duke Energy’s captive insurance company, Bison, and its affiliates, consistent with companies engaged in similar commercial operations with similar type properties. The Duke Energy Registrants’ coverage includes (i) commercial general liability coverage for liabilities arising to third parties for bodily injury and property damage; (ii) workers’ compensation; (iii) automobile liability coverage; and (iv) property coverage for all real and personal property damage. Real and personal property damage coverage excludes electric transmission and distribution lines, but includes damages arising from boiler and machinery breakdowns, earthquakes, flood damage and extra expense, but not outage or replacement power coverage. All coverage is subject to certain deductibles or retentions, sublimits, exclusions, terms and conditions common for companies with similar types of operations. The Duke Energy Registrants self-insure their electric transmission and distribution lines against loss due to storm damage and other natural disasters. As discussed further in Note 4 , Duke Energy Florida maintains a storm damage reserve and has a regulatory mechanism to recover the cost of named storms on an expedited basis. The cost of the Duke Energy Registrants’ coverage can fluctuate from year to year reflecting claims history and conditions of the insurance and reinsurance markets. In the event of a loss, terms and amounts of insurance and reinsurance available might not be adequate to cover claims and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered by other sources, could have a material effect on the Duke Energy Registrants’ results of operations, cash flows or financial position. Each company is responsible to the extent losses may be excluded or exceed limits of the coverage available. Nuclear Insurance Duke Energy Carolinas owns and operates McGuire and Oconee and operates and has a partial ownership interest in Catawba. McGuire and Catawba each have two reactors. Oconee has three reactors. The other joint owners of Catawba reimburse Duke Energy Carolinas for certain expenses associated with nuclear insurance per the Catawba joint owner agreements. Duke Energy Progress owns and operates Robinson, Brunswick and Harris. Robinson and Harris each have one reactor. Brunswick has two reactors. Duke Energy Florida owns Crystal River Unit 3, which permanently ceased operation in 2013 and reached a SAFSTOR condition in January 2018 after the successful transfer of all used nuclear fuel assemblies to an on-site dry cask storage facility. In the event of a loss, terms and amounts of insurance available might not be adequate to cover property damage and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered by other sources, could have a material effect on Duke Energy Carolinas’, Duke Energy Progress’ and Duke Energy Florida’s results of operations, cash flows or financial position. Each company is responsible to the extent losses may be excluded or exceed limits of the coverage available. Nuclear Liability Coverage The Price-Anderson Act requires owners of nuclear reactors to provide for public nuclear liability protection per nuclear incident up to a maximum total financial protection liability. The maximum total financial protection liability, which is approximately $13.9 billion , is subject to change every five years for inflation and for the number of licensed reactors. Total nuclear liability coverage consists of a combination of private primary nuclear liability insurance coverage and a mandatory industry risk-sharing program to provide for excess nuclear liability coverage above the maximum reasonably available private primary coverage. The U.S. Congress could impose revenue-raising measures on the nuclear industry to pay claims. Primary Liability Insurance Duke Energy Carolinas and Duke Energy Progress have purchased the maximum reasonably available private primary nuclear liability insurance as required by law, which is $450 million per station. Duke Energy Florida has purchased $100 million primary nuclear liability insurance in compliance with the law. Excess Liability Program This program provides $13.5 billion of coverage per incident through the Price-Anderson Act’s mandatory industrywide excess secondary financial protection program of risk pooling. This amount is the product of potential cumulative retrospective premium assessments of $138 million times the current 98 licensed commercial nuclear reactors in the U.S. Under this program, licensees could be assessed retrospective premiums to compensate for public nuclear liability damages in the event of a nuclear incident at any licensed facility in the U.S. Retrospective premiums may be assessed at a rate not to exceed $20.5 million per year per licensed reactor for each incident. The assessment may be subject to state premium taxes. Nuclear Property and Accidental Outage Coverage Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida are members of Nuclear Electric Insurance Limited (NEIL), an industry mutual insurance company, which provides property damage, nuclear accident decontamination and premature decommissioning insurance for each station for losses resulting from damage to its nuclear plants, either due to accidents or acts of terrorism. Additionally, NEIL provides accidental outage coverage for losses in the event of a major accidental outage at an insured nuclear station. Pursuant to regulations of the NRC, each company’s property damage insurance policies provide that all proceeds from such insurance be applied, first, to place the plant in a safe and stable condition after a qualifying accident and second, to decontaminate the plant before any proceeds can be used for decommissioning, plant repair or restoration. Losses resulting from acts of terrorism are covered as common occurrences, such that if terrorist acts occur against one or more commercial nuclear power plants insured by NEIL within a 12-month period, they would be treated as one event and the owners of the plants where the act occurred would share one full limit of liability. The full limit of liability is currently $3.2 billion . NEIL sublimits the total aggregate for all of their policies for non-nuclear terrorist events to approximately $1.8 billion . Each nuclear facility has accident property damage, nuclear accident decontamination and premature decommissioning liability insurance from NEIL with limits of $1.5 billion , except for Crystal River Unit 3. Crystal River Unit 3’s limit is $50 million and is on an actual cash value basis. All nuclear facilities except for Catawba and Crystal River Unit 3 also share an additional $1.25 billion nuclear accident insurance limit above their dedicated underlying limit. This shared additional excess limit is not subject to reinstatement in the event of a loss. Catawba has a dedicated $1.25 billion of additional nuclear accident insurance limit above its dedicated underlying limit. Catawba and Oconee also have an additional $750 million of non-nuclear accident property damage limit. All coverages are subject to sublimits and significant deductibles. NEIL’s Accidental Outage policy provides some coverage, similar to business interruption, for losses in the event of a major accident property damage outage of a nuclear unit. Coverage is provided on a weekly limit basis after a significant waiting period deductible and at 100% of the applicable weekly limits for 52 weeks and 80% of the applicable weekly limits for up to the next 110 weeks. Coverage is provided until these applicable weekly periods are met, where the accidental outage policy limit will not exceed $490 million for McGuire and Catawba, $462 million for Brunswick and Harris, $406 million for Oconee and $364 million for Robinson. NEIL sublimits the accidental outage recovery up to the first 104 weeks of coverage not to exceed $328 million from non-nuclear accidental property damage. Coverage amounts decrease in the event more than one unit at a station is out of service due to a common accident. All coverages are subject to sublimits and significant deductibles. Potential Retroactive Premium Assessments In the event of NEIL losses, NEIL’s board of directors may assess member companies' retroactive premiums of amounts up to 10 times their annual premiums for up to six years after a loss. NEIL has never exercised this assessment. The maximum aggregate annual retrospective premium obligations for Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida are $155 million , $94 million and $1 million , respectively. Duke Energy Carolinas' maximum assessment amount includes 100% of potential obligations to NEIL for jointly owned reactors. Duke Energy Carolinas would seek reimbursement from the joint owners for their portion of these assessment amounts. ENVIRONMENTAL The Duke Energy Registrants are subject to federal, state and local laws regarding air and water quality, hazardous and solid waste disposal, coal ash and other environmental matters. These laws can be changed from time to time, imposing new obligations on the Duke Energy Registrants. The following environmental matters impact all of the Duke Energy Registrants. Remediation Activities In addition to the ARO recorded as a result of various environmental regulations, discussed in Note 10 , the Duke Energy Registrants are responsible for environmental remediation at various sites. These include certain properties that are part of ongoing operations and sites formerly owned or used by Duke Energy entities. These sites are in various stages of investigation, remediation and monitoring. Managed in conjunction with relevant federal, state and local agencies, remediation activities vary based upon site conditions and location, remediation requirements, complexity and sharing of responsibility. If remediation activities involve joint and several liability provisions, strict liability, or cost recovery or contribution actions, the Duke Energy Registrants could potentially be held responsible for environmental impacts caused by other potentially responsible parties and may also benefit from insurance policies or contractual indemnities that cover some or all cleanup costs. Liabilities are recorded when losses become probable and are reasonably estimable. The total costs that may be incurred cannot be estimated because the extent of environmental impact, allocation among potentially responsible parties, remediation alternatives and/or regulatory decisions have not yet been determined at all sites. Additional costs associated with remediation activities are likely to be incurred in the future and could be significant. Costs are typically expensed as Operation, maintenance and other in the Consolidated Statements of Operations unless regulatory recovery of the costs is deemed probable. The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Accounts payable within Current Liabilities and Other within Other Noncurrent Liabilities on the Consolidated Balance Sheets. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at December 31, 2016 $ 98 $ 10 $ 18 $ 3 $ 14 $ 59 $ 10 $ 1 Provisions/adjustments 8 3 3 2 2 3 (4 ) 1 Cash reductions (25 ) (3 ) (6 ) (2 ) (4 ) (15 ) (1 ) — Balance at December 31, 2017 81 10 15 3 12 47 5 2 Provisions/adjustments 26 3 2 3 (2 ) 21 1 1 Cash reductions (30 ) (2 ) (6 ) (2 ) (4 ) (20 ) (1 ) (1 ) Balance at December 31, 2018 77 11 11 4 6 48 5 2 Provisions/adjustments 33 6 9 2 5 11 — 7 Cash reductions (52 ) (6 ) (4 ) (2 ) (2 ) (40 ) (1 ) (1 ) Balance at December 31, 2019 $ 58 $ 11 $ 16 $ 4 $ 9 $ 19 $ 4 $ 8 Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 59 Duke Energy Carolinas 11 Duke Energy Ohio 42 Piedmont 2 LITIGATION Duke Energy Carolinas and Duke Energy Progress NCDEQ Closure Litigation The Coal Ash Act requires CCR surface impoundments in North Carolina to be closed, with the closure method and timing based on a risk ranking classification determined by legislation or state regulators. The NCDEQ previously classified the impoundments at Allen, Belews Creek, Rogers, Marshall, Mayo and Roxboro as low risk. The Coal Ash Act allowed a range of closure options for low risk rated basins. On April 1, 2019, NCDEQ issued a closure determination (NCDEQ's April 1 Order) requiring Duke Energy Carolinas and Duke Energy Progress to excavate all remaining coal ash impoundments at these facilities. On April 26, 2019, Duke Energy Carolinas and Duke Energy Progress filed Petitions for Contested Case Hearings in the Office of Administrative Hearings to challenge NCDEQ's April 1 Order. On May 9, 2019, NCDEQ issued a supplemental order requiring that closure plans be submitted on December 31, 2019, but providing that the corrective action plans are not due until March 31, 2020. Duke Energy Carolinas and Duke Energy Progress filed amended petitions on May 24, 2019, incorporating the May 9, 2019, order. On December 31, 2019, the parties executed a settlement agreement resolving the closure method for each of these sites. Duke Energy Carolinas and Duke Energy Progress agreed to excavate seven of the nine remaining coal ash basins at these sites with ash moved to on-site lined landfills, including two at Allen, one at Belews Creek, one at Mayo, one at Roxboro, and two at Rogers. At the two remaining basins at Marshall and Roxboro, uncapped basin ash will be excavated and moved to lined landfills. Those portions of the basins at Marshall and Roxboro, which were previously filled with ash and on which permitted facilities were constructed, will not be disturbed and will be closed pursuant to other state regulations. On February 5, 2020, the North Carolina Superior court entered a consent order, after which this litigation was dismissed on February 11, 2020. Coal Ash Insurance Coverage Litigation In March 2017, Duke Energy Carolinas and Duke Energy Progress filed a civil action in the North Carolina Superior Court against various insurance providers. The lawsuit seeks payment for coal ash-related liabilities covered by third-party liability insurance policies. The insurance policies were issued between 1971 and 1986 and provide third-party liability insurance for property damage. The civil action seeks damages for breach of contract and indemnification for costs arising from the Coal Ash Act and the EPA CCR rule at 15 coal-fired plants in North Carolina and South Carolina. Despite a stay of the litigation from May 2019 through September 2019 to allow the parties to discuss potential resolution, no resolution was reached, and litigation resumed. In February and March 2020, the Court will hear arguments on numerous cross motions filed by the parties to seek legal determinations concerning, among other issues, the appropriate insurance allocation methods, the trigger of the applicable coverages and several coverage defenses raised by the insurance providers. Trial is scheduled for February 2021. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. NCDEQ State Enforcement Actions In the first quarter of 2013, SELC sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged CWA violations from coal ash basins at two coal-fired power plants in North Carolina. The NCDEQ filed enforcement actions against Duke Energy Carolinas and Duke Energy Progress alleging violations of water discharge permits and North Carolina groundwater standards. The cases have been consolidated and are being heard before a single judge in the North Carolina Superior Court. On August 16, 2013, the NCDEQ filed an enforcement action against Duke Energy Carolinas and Duke Energy Progress related to the remaining coal-fired power plants in North Carolina, alleging violations of the CWA and violations of the North Carolina groundwater standards. Both of these cases have been assigned to the judge handling the enforcement actions discussed above. SELC is representing several environmental groups who have been permitted to intervene in these cases. The court issued orders in 2016 granting Motions for Partial Summary Judgment for seven of the 14 North Carolina plants with coal ash basins named in the enforcement actions. On February 13, 2017, the court issued an order denying motions for partial summary judgment brought by both the environmental groups and Duke Energy Carolinas and Duke Energy Progress for the remaining seven plants. On March 15, 2017, Duke Energy Carolinas and Duke Energy Progress filed a Notice of Appeal with the North Carolina Court of Appeals to challenge the trial court’s order. The parties were unable to reach an agreement at mediation in April 2017 and submitted briefs to the trial court on remaining issues to be tried. On August 1, 2018, the Court of Appeals dismissed the appeal. Pursuant to the terms of the December 31, 2019, settlement agreement, discussed above, between Duke Energy Carolinas, Duke Energy Progress, NCDEQ and the community groups represented by the SELC, this litigation was dismissed on February 5, 2020, upon entry of the consent order in the North Carolina Superior Court. Federal Citizens Suits On June 13, 2016, Roanoke River Basin Association (RRBA) filed a federal citizen suit in the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Mayo Plant. On August 19, 2016, Duke Energy Progress filed a Motion to Dismiss. On April 26, 2017, the court entered an order dismissing four of the claims in the federal citizen suit. Two claims relating to alleged violations of National Pollution Discharge Elimination System (NPDES) permit provisions survived the motion to dismiss, and Duke Energy Progress filed its response on May 10, 2017. Duke Energy Progress and RRBA each filed motions for summary judgment on March 23, 2018. On May 16, 2017, RRBA filed a federal citizen suit in the U.S. District Court for the Middle District of North Carolina, which asserts two claims relating to alleged violations of NPDES permit provisions at the Roxboro Plant and one claim relating to the use of nearby water bodies. Duke Energy Progress and RRBA each filed motions for summary judgment on April 17, 2018. On May 8, 2018, on motion from Duke Energy Progress, the court ordered trial in both of the above matters to be consolidated. On April 5, 2019, Duke Energy Progress filed a motion to stay the case following the NCDEQ’s April 1 Order. On August 2, 2019, the court ordered that this case is stayed. On December 5, 2017, various parties filed a federal citizen suit in the U.S. District Court for the Middle District of North Carolina for alleged violations at Duke Energy Carolinas' Belews Creek under the CWA. Duke Energy Carolinas' answer to the complaint was filed on August 27, 2018. On October 10, 2018, Duke Energy Carolinas filed Motions to Dismiss for lack of standing, Motion for Judgment on the Pleadings and Motion to Stay Discovery. On January 9, 2019, the court entered an order denying Duke Energy Carolinas' motion to stay discovery. There has been no ruling on the other pending motions. On April 5, 2019, Duke Energy Carolinas filed a motion to stay the case following the NCDEQ’s April 1 Order. On August 2, 2019, the court ordered that this case is stayed. On December 31, 2019, Duke Energy Carolinas, Duke Energy Progress, the NCDEQ and various community groups including RRBA entered into a comprehensive settlement that, among other things, resolves the method of closure at the Mayo, Roxboro and Belews Creek ash basins. On February 5, 2020, the North Carolina Superior Court entered a consent order confirming the terms of the settlement agreement, upon which RRBA filed stipulations on February 11, 2020 voluntarily dismissing all three of these federal citizen suits with prejudice. Duke Energy Carolinas Asbestos-related Injuries and Damages Claims Duke Energy Carolinas has experienced numerous claims for indemnification and medical cost reimbursement related to asbestos exposure. These claims relate to damages for bodily injuries alleged to have arisen from exposure to or use of asbestos in connection with construction and maintenance activities conducted on its electric generation plants prior to 1985. As of December 31, 2019 , there were 123 asserted claims for non-malignant cases with the cumulative relief sought of up to $32 million and 49 asserted claims for malignant cases with the cumulative relief sought of up to $16 million . Based on Duke Energy Carolinas’ experience, it is expected that the ultimate resolution of most of these claims likely will be less than the amount claimed. Duke Energy Carolinas has recognized asbestos-related reserves of $604 million and $630 million at December 31, 2019 , and 2018 , respectively. These reserves are classified in Other within Other Noncurrent Liabilities and Other within Current Liabilities on the Consolidated Balance Sheets. These reserves are based upon Duke Energy Carolinas' best estimate for current and future asbestos claims through 2039 and are recorded on an undiscounted basis. In light of the uncertainties inherent in a longer-term forecast, management does not believe they can reasonably estimate the indemnity and medical costs that might be incurred after 2039 related to such potential claims. It is possible Duke Energy Carolinas may incur asbestos liabilities in excess of the recorded reserves. Duke Energy Carolinas has third-party insurance to cover certain losses related to asbestos-related injuries and damages above an aggregate self-insured retention. Duke Energy Carolinas’ cumulative payments began to exceed the self-insurance retention in 2008. Future payments up to the policy limit will be reimbursed by the third-party insurance carrier. The insurance policy limit for potential future insurance recoveries indemnification and medical cost claim payments is $747 million in excess of the self-insured retention. Receivables for insurance recoveries were $742 million and $739 million at December 31, 2019 , and 2018 , respectively. These amounts are classified in Other within Other Noncurrent Assets and Receivables within Current Assets on the Consolidated Balance Sheets. Duke Energy Carolinas is not aware of any uncertainties regarding the legal sufficiency of insurance claims. Duke Energy Carolinas believes the insurance recovery asset is probable of recovery as the insurance carrier continues to have a strong financial strength rating. Duke Energy Progress and Duke Energy Florida Spent Nuclear Fuel Matters On June 18, 2018, Duke Energy Progress and Duke Energy Florida sued the U.S. in the U.S. Court of Federal Claims for damages incurred for the period 2014 through 2018. The lawsuit claimed the Department of Energy breached a contract in failing to accept spent nuclear fuel under the Nuclear Waste Policy Act of 1982 and asserted damages for the cost of on-site storage in the amount of $100 million and $203 million for Duke Energy Progress and Duke Energy Florida, respectively. Discovery is ongoing and a trial is expected to occur in early 2021. Duke Energy Florida Fluor Contract Litigation On January 29, 2019, Fluor filed a breach of contract lawsuit in the U.S. District Court for the Middle District of Florida against Duke Energy Florida related to an EPC agreement for the CC natural gas plant in Citrus County, Florida. Fluor filed an amended complaint on February 13, 2019. Fluor’s multicount complaint seeks civil, statutory and contractual remedies related to Duke Energy Florida’s $67 million draw in early 2019, on Fluor’s letter of credit and offset of invoiced amounts. Duke Energy Florida moved to dismiss all counts of Fluor's amended complaint, and on April 16, 2019, the court dismissed Fluor's complaint without prejudice. On April 26, 2019, Fluor filed a second amended complaint. On August 1, 2019, Duke Energy Florida and Fluor reached a settlement to resolve the pending litigation and other outstanding issues related to completing the Citrus County CC. Pursuant to the terms of the settlement, Fluor filed a notice of voluntary dismissal, and on August 27, 2019, the court dismissed the case with prejudice. As a result of the settlement with Fluor, Duke Energy Florida recorded a $36 million reduction to a prior-year impairment within Impairment charges on Duke Energy's Consolidated Statements of Operations in 2019. Other Litigation and Legal Proceedings The Duke Energy Registrants are involved in other legal, tax and regulatory proceedings arising in the ordinary course of business, some of which involve significant amounts. The Duke Energy Registrants believe the final disposition of these proceedings will not have a material effect on their results of operations, cash flows or financial position. The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos-related reserves. Reserves are classified on the Consolidated Balance Sheets in Other within Other Noncurrent Liabilities and Other within Current Liabilities. The reasonably possible range of loss in excess of recorded reserves is not material, other than as described above. December 31, (in millions) 2019 2018 Reserves for Legal Matters Duke Energy $ 62 $ 65 Duke Energy Carolinas 2 9 Progress Energy 55 54 Duke Energy Progress 12 12 Duke Energy Florida 22 24 Piedmont 1 1 OTHER COMMITMENTS AND CONTINGENCIES General As part of their normal business, the Duke Energy Registrants are party to various financial guarantees, performance guarantees and other contractual commitments to extend guarantees of credit and other assistance to various subsidiaries, investees and other third parties. These guarantees involve elements of performance and credit risk, which are not fully recognized on the Consolidated Balance Sheets and have uncapped maximum potential payments. See Note 8 for more information. Purchase Obligations Purchased Power Duke Energy Progress, Duke Energy Florida and Duke Energy Ohio have ongoing purchased power contracts, including renewable energy contracts, with other utilities, wholesale marketers, co-generators and qualified facilities. These purchased power contracts generally provide for capacity and energy payments. In addition, Duke Energy Progress and Duke Energy Florida have various contracts to secure transmission rights. The following table presents executory purchased power contracts with terms exceeding one year, excluding contracts classified as leases. Minimum Purchase Amount at December 31, 2019 Contract (in millions) Expiration 2020 2021 2022 2023 2024 Thereafter Total Duke Energy Progress (a) 2021-2032 $ 46 $ 66 $ 63 $ 55 $ 56 $ 123 $ 409 Duke Energy Florida (b) 2021-2025 374 356 354 374 262 91 1,811 Duke Energy Ohio (c)(d) 2021-2022 132 107 32 — — — 271 (a) Contracts represent either 100% of net plant output or vary. (b) Contracts represent between 81% and 100% of net plant output. (c) Contracts represent between 1% and 9% of net plant output. (d) Excludes PPA with OVEC. See Note 18 for additional information. Gas Supply and Capacity Contracts Duke Energy Ohio and Piedmont routinely enter into long-term natural gas supply commodity and capacity commitments and other agreements that commit future cash flows to acquire services needed in their businesses. These commitments include pipeline and storage capacity contracts and natural gas supply contracts to provide service to customers. Costs arising from the natural gas supply commodity and capacity commitments, while significant, are pass-through costs to customers and are generally fully recoverable through the fuel adjustment or PGA procedures and prudence reviews in North Carolina and South Carolina and under the Tennessee Incentive Plan in Tennessee. In the Midwest, these costs are recovered via the Gas Cost Recovery Rate in Ohio or the Gas Cost Adjustment Clause in Kentucky. The time periods for fixed payments under pipeline and storage capacity contracts are up to 15 years . The time periods for fixed payments under natural gas supply contracts are up to six years . The time period for the natural gas supply purchase commitments is up to 11 years . Certain storage and pipeline capacity contracts require the payment of demand charges that are based on rates approved by the FERC in order to maintain rights to access the natural gas storage or pipeline capacity on a firm basis during the contract term. The demand charges that are incurred in each period are recognized in the Consolidated Statements of Operations and Comprehensive Income as part of natural gas purchases and are included in Cost of natural gas. The following table presents future unconditional purchase obligations under natural gas supply and capacity contracts as of December 31, 2019 . (in millions) Duke Energy Duke Energy Ohio Piedmont 2020 $ 297 $ 39 $ 258 2021 280 33 247 2022 225 14 211 2023 129 3 126 2024 118 — 118 Thereafter 714 — 714 Total $ 1,763 $ 89 $ 1,674

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	LEASES As described in Note 1 , Duke Energy adopted the revised accounting guidance for Leases effective January 1, 2019, using the modified retrospective method of adoption, which does not require restatement of prior year reported results. Adoption of the new standard resulted in the recording of ROU assets and operating lease liabilities as follows: As of January 1, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont ROU assets $ 1,750 $ 153 $ 863 $ 407 $ 456 $ 23 $ 61 $ 26 Operating lease liabilities – current 205 28 96 35 61 1 4 4 Operating lease liabilities – noncurrent 1,504 127 766 371 395 22 58 25 As part of its operations, Duke Energy leases certain aircraft, space on communication towers, industrial equipment, fleet vehicles, fuel transportation (barges and railcars), land and office space under various terms and expiration dates. Additionally, Duke Energy Carolinas, Duke Energy Progress and Duke Energy Indiana have finance leases related to firm natural gas pipeline transportation capacity. Duke Energy Progress and Duke Energy Florida have entered into certain PPAs, which are classified as finance and operating leases. Duke Energy has certain lease agreements, which include variable lease payments that are based on the usage of an asset. These variable lease payments are not included in the measurement of the ROU assets or operating lease liabilities on the Consolidated Financial Statements. Certain Duke Energy lease agreements include options for renewal and early termination. The intent to renew a lease varies depending on the lease type and asset. Renewal options that are reasonably certain to be exercised are included in the lease measurements. The decision to terminate a lease early is dependent on various economic factors. No termination options have been included in any of the lease measurements. Duke Energy Carolinas entered into a sale-leaseback arrangement in December 2019, to construct and occupy an office tower. The lease agreement was evaluated as a sale-leaseback of real estate and it was determined that the transaction did not qualify for sale-leaseback accounting. As a result, the transaction is being accounted for as a financing. For this transaction, Duke Energy Carolinas will continue to record the real estate on the Consolidated Balance Sheets within Property, Plant and Equipment as if it were the legal owner and will continue to recognize depreciation expense over the estimated useful life. In addition, a liability will be recorded for the failed sale-leaseback obligation within Long-Term Debt on the Consolidated Balance Sheets, with the monthly lease payments commencing after the construction phase being split between interest expense and principal pay down of the debt. Duke Energy operates various renewable energy projects and sells the generated output to utilities, electric cooperatives, municipalities and commercial and industrial customers through long-term PPAs. In certain situations, these PPAs and the associated renewable energy projects qualify as operating leases. Rental income from these leases is accounted for as Nonregulated electric and other revenues in the Consolidated Statements of Operations. There are no minimum lease payments as all payments are contingent based on actual electricity generated by the renewable energy projects. Contingent lease payments were $264 million , $268 million and $262 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,349 million and $3,358 million and accumulated depreciation of $721 million and $602 million at December 31, 2019 , and 2018 , respectively. These assets are principally classified as nonregulated electric generation and transmission assets. Piedmont has an agreement with Duke Energy Carolinas for the construction and transportation of natural gas pipelines to supply its natural gas plant needs. Piedmont accounts for this pipeline lateral contract as a lessor and sales-type lease since the present value of the sum of the lease payments equals the fair value of the asset. As of December 31, 2019 , the pipeline lateral assets owned by Piedmont had a current net investment basis of $4 million and a long-term net investment basis of $70 million . These assets are classified in Other, within Current Assets and Other Noncurrent Assets, respectively, on Piedmont's Consolidated Balance Sheets. Duke Energy Carolinas accounts for the contract as a finance lease. The activity for this contract is eliminated in consolidation at Duke Energy. The following table presents the components of lease expense. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Operating lease expense (a) $ 292 $ 47 $ 161 $ 69 $ 92 $ 11 $ 20 $ 5 Short-term lease expense (a) 16 5 9 4 5 1 2 — Variable lease expense (a) 47 22 22 16 6 — 1 1 Finance lease expense Amortization of leased assets (b) 111 6 21 5 16 1 — — Interest on lease liabilities (c) 61 15 42 33 9 — 1 — Total finance lease expense 172 21 63 38 25 1 1 — Total lease expense $ 527 $ 95 $ 255 $ 127 $ 128 $ 13 $ 24 $ 6 (a) Included in Operations, maintenance and other or, for barges and railcars, Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. (b) Included in Depreciation and amortization on the Consolidated Statements of Operations. (c) Included in Interest Expense on the Consolidated Statements of Operations. The following table presents rental expense for operating leases, as reported under the former lease standard. These amounts are included in Operation, maintenance and other and Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Years Ended December 31, (in millions) 2018 2017 Duke Energy $ 268 $ 241 Duke Energy Carolinas 49 44 Progress Energy 143 130 Duke Energy Progress 75 75 Duke Energy Florida 68 55 Duke Energy Ohio 13 15 Duke Energy Indiana 21 23 Piedmont 11 7 The following table presents operating lease maturities and a reconciliation of the undiscounted cash flows to operating lease liabilities. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 268 $ 31 $ 123 $ 51 $ 72 $ 2 $ 5 $ 5 2021 216 19 99 44 55 2 4 5 2022 201 19 95 40 55 2 4 5 2023 191 17 95 41 54 2 4 5 2024 176 13 95 41 54 2 4 5 Thereafter 984 57 462 283 179 21 64 5 Total operating lease payments 2,036 156 969 500 469 31 85 30 Less: present value discount (396 ) (27 ) (177 ) (109 ) (68 ) (9 ) (27 ) (3 ) Total operating lease liabilities (a) $ 1,640 $ 129 $ 792 $ 391 $ 401 $ 22 $ 58 $ 27 (a) Certain operating lease payments include renewal options that are reasonably certain to be exercised. The following table presents future minimum lease payments under operating leases, which at inception had a noncancelable term of more than one year, as reported under the former lease standard. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2019 $ 239 $ 33 $ 97 $ 49 $ 48 $ 2 $ 6 $ 5 2020 219 29 90 46 44 2 5 5 2021 186 19 79 37 42 2 4 5 2022 170 19 76 34 42 2 4 5 2023 160 17 77 35 42 2 5 6 Thereafter 1,017 68 455 314 141 23 66 11 Total $ 1,991 $ 185 $ 874 $ 515 $ 359 $ 33 $ 90 $ 37 The following table presents finance lease maturities and a reconciliation of the undiscounted cash flows to finance lease liabilities. December 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana 2020 $ 181 $ 28 $ 69 $ 44 $ 25 $ 1 2021 186 23 69 44 25 1 2022 173 23 69 44 25 1 2023 175 23 69 44 25 1 2024 121 23 55 44 11 1 Thereafter 823 314 539 528 11 27 Total finance lease payments 1,659 434 870 748 122 32 Less: amounts representing interest (690 ) (255 ) (465 ) (441 ) (24 ) (22 ) Total finance lease liabilities $ 969 $ 179 $ 405 $ 307 $ 98 $ 10 The following table presents future minimum lease payments under finance leases, as reported under the former lease standard. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2019 $ 170 $ 20 $ 45 $ 20 $ 25 $ 2 $ 1 2020 174 20 46 21 25 — 1 2021 177 15 45 20 25 — 1 2022 165 15 45 21 24 — 1 2023 165 15 45 21 24 — 1 Thereafter 577 204 230 209 21 — 27 Minimum annual payments 1,428 289 456 312 144 2 32 Less: amount representing interest (487 ) (180 ) (205 ) (175 ) (30 ) — (22 ) Total $ 941 $ 109 $ 251 $ 137 $ 114 $ 2 $ 10 The following tables contain additional information related to leases. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Classification Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Assets Operating Operating lease ROU assets, net $ 1,658 $ 123 $ 788 $ 387 $ 401 $ 21 $ 57 $ 24 Finance Net property, plant and equipment 926 198 443 308 135 — 7 — Total lease assets $ 2,584 $ 321 $ 1,231 $ 695 $ 536 $ 21 $ 64 $ 24 Liabilities Current Operating Other current liabilities $ 208 $ 27 $ 95 $ 37 $ 58 $ 1 $ 3 $ 4 Finance Current maturities of long-term debt 119 7 24 6 18 — — — Noncurrent Operating Operating lease liabilities 1,432 102 697 354 343 21 55 23 Finance Long-Term Debt 850 172 381 301 80 — 10 — Total lease liabilities $ 2,609 $ 308 $ 1,197 $ 698 $ 499 $ 22 $ 68 $ 27 Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Cash paid for amounts included in the measurement of lease liabilities (a) Operating cash flows from operating leases $ 285 $ 34 $ 131 $ 53 $ 78 $ 2 $ 7 $ 7 Operating cash flows from finance leases 61 15 42 33 9 — 1 — Financing cash flows from finance leases 111 6 21 5 16 1 — — Lease assets obtained in exchange for new lease liabilities (non-cash) Operating (b) $ 194 $ 44 $ 30 $ 30 $ — $ — $ — $ 1 Finance 251 76 175 175 — — — — (a) No amounts were classified as investing cash flows from operating leases for the year ended December 31, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Weighted average remaining lease term (years) Operating leases 11 9 10 12 8 17 18 6 Finance leases 13 19 16 18 11 — 26 — Weighted average discount rate (a) Operating leases 3.9 % 3.5 % 3.8 % 3.9 % 3.8 % 4.2 % 4.1 % 3.6 % Finance leases 8.1 % 11.8 % 11.9 % 12.4 % 8.3 % — % 11.9 % — % (a) The discount rate is calculated using the rate implicit in a lease if it is readily determinable. Generally, the rate used by the lessor is not provided to Duke Energy and in these cases the incremental borrowing rate is used. Duke Energy will typically use its fully collateralized incremental borrowing rate as of the commencement date to calculate and record the lease. The incremental borrowing rate is influenced by the lessee’s credit rating and lease term and as such may differ for individual leases, embedded leases or portfolios of leased assets.
Leases	LEASES As described in Note 1 , Duke Energy adopted the revised accounting guidance for Leases effective January 1, 2019, using the modified retrospective method of adoption, which does not require restatement of prior year reported results. Adoption of the new standard resulted in the recording of ROU assets and operating lease liabilities as follows: As of January 1, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont ROU assets $ 1,750 $ 153 $ 863 $ 407 $ 456 $ 23 $ 61 $ 26 Operating lease liabilities – current 205 28 96 35 61 1 4 4 Operating lease liabilities – noncurrent 1,504 127 766 371 395 22 58 25 As part of its operations, Duke Energy leases certain aircraft, space on communication towers, industrial equipment, fleet vehicles, fuel transportation (barges and railcars), land and office space under various terms and expiration dates. Additionally, Duke Energy Carolinas, Duke Energy Progress and Duke Energy Indiana have finance leases related to firm natural gas pipeline transportation capacity. Duke Energy Progress and Duke Energy Florida have entered into certain PPAs, which are classified as finance and operating leases. Duke Energy has certain lease agreements, which include variable lease payments that are based on the usage of an asset. These variable lease payments are not included in the measurement of the ROU assets or operating lease liabilities on the Consolidated Financial Statements. Certain Duke Energy lease agreements include options for renewal and early termination. The intent to renew a lease varies depending on the lease type and asset. Renewal options that are reasonably certain to be exercised are included in the lease measurements. The decision to terminate a lease early is dependent on various economic factors. No termination options have been included in any of the lease measurements. Duke Energy Carolinas entered into a sale-leaseback arrangement in December 2019, to construct and occupy an office tower. The lease agreement was evaluated as a sale-leaseback of real estate and it was determined that the transaction did not qualify for sale-leaseback accounting. As a result, the transaction is being accounted for as a financing. For this transaction, Duke Energy Carolinas will continue to record the real estate on the Consolidated Balance Sheets within Property, Plant and Equipment as if it were the legal owner and will continue to recognize depreciation expense over the estimated useful life. In addition, a liability will be recorded for the failed sale-leaseback obligation within Long-Term Debt on the Consolidated Balance Sheets, with the monthly lease payments commencing after the construction phase being split between interest expense and principal pay down of the debt. Duke Energy operates various renewable energy projects and sells the generated output to utilities, electric cooperatives, municipalities and commercial and industrial customers through long-term PPAs. In certain situations, these PPAs and the associated renewable energy projects qualify as operating leases. Rental income from these leases is accounted for as Nonregulated electric and other revenues in the Consolidated Statements of Operations. There are no minimum lease payments as all payments are contingent based on actual electricity generated by the renewable energy projects. Contingent lease payments were $264 million , $268 million and $262 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,349 million and $3,358 million and accumulated depreciation of $721 million and $602 million at December 31, 2019 , and 2018 , respectively. These assets are principally classified as nonregulated electric generation and transmission assets. Piedmont has an agreement with Duke Energy Carolinas for the construction and transportation of natural gas pipelines to supply its natural gas plant needs. Piedmont accounts for this pipeline lateral contract as a lessor and sales-type lease since the present value of the sum of the lease payments equals the fair value of the asset. As of December 31, 2019 , the pipeline lateral assets owned by Piedmont had a current net investment basis of $4 million and a long-term net investment basis of $70 million . These assets are classified in Other, within Current Assets and Other Noncurrent Assets, respectively, on Piedmont's Consolidated Balance Sheets. Duke Energy Carolinas accounts for the contract as a finance lease. The activity for this contract is eliminated in consolidation at Duke Energy. The following table presents the components of lease expense. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Operating lease expense (a) $ 292 $ 47 $ 161 $ 69 $ 92 $ 11 $ 20 $ 5 Short-term lease expense (a) 16 5 9 4 5 1 2 — Variable lease expense (a) 47 22 22 16 6 — 1 1 Finance lease expense Amortization of leased assets (b) 111 6 21 5 16 1 — — Interest on lease liabilities (c) 61 15 42 33 9 — 1 — Total finance lease expense 172 21 63 38 25 1 1 — Total lease expense $ 527 $ 95 $ 255 $ 127 $ 128 $ 13 $ 24 $ 6 (a) Included in Operations, maintenance and other or, for barges and railcars, Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. (b) Included in Depreciation and amortization on the Consolidated Statements of Operations. (c) Included in Interest Expense on the Consolidated Statements of Operations. The following table presents rental expense for operating leases, as reported under the former lease standard. These amounts are included in Operation, maintenance and other and Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Years Ended December 31, (in millions) 2018 2017 Duke Energy $ 268 $ 241 Duke Energy Carolinas 49 44 Progress Energy 143 130 Duke Energy Progress 75 75 Duke Energy Florida 68 55 Duke Energy Ohio 13 15 Duke Energy Indiana 21 23 Piedmont 11 7 The following table presents operating lease maturities and a reconciliation of the undiscounted cash flows to operating lease liabilities. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 268 $ 31 $ 123 $ 51 $ 72 $ 2 $ 5 $ 5 2021 216 19 99 44 55 2 4 5 2022 201 19 95 40 55 2 4 5 2023 191 17 95 41 54 2 4 5 2024 176 13 95 41 54 2 4 5 Thereafter 984 57 462 283 179 21 64 5 Total operating lease payments 2,036 156 969 500 469 31 85 30 Less: present value discount (396 ) (27 ) (177 ) (109 ) (68 ) (9 ) (27 ) (3 ) Total operating lease liabilities (a) $ 1,640 $ 129 $ 792 $ 391 $ 401 $ 22 $ 58 $ 27 (a) Certain operating lease payments include renewal options that are reasonably certain to be exercised. The following table presents future minimum lease payments under operating leases, which at inception had a noncancelable term of more than one year, as reported under the former lease standard. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2019 $ 239 $ 33 $ 97 $ 49 $ 48 $ 2 $ 6 $ 5 2020 219 29 90 46 44 2 5 5 2021 186 19 79 37 42 2 4 5 2022 170 19 76 34 42 2 4 5 2023 160 17 77 35 42 2 5 6 Thereafter 1,017 68 455 314 141 23 66 11 Total $ 1,991 $ 185 $ 874 $ 515 $ 359 $ 33 $ 90 $ 37 The following table presents finance lease maturities and a reconciliation of the undiscounted cash flows to finance lease liabilities. December 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana 2020 $ 181 $ 28 $ 69 $ 44 $ 25 $ 1 2021 186 23 69 44 25 1 2022 173 23 69 44 25 1 2023 175 23 69 44 25 1 2024 121 23 55 44 11 1 Thereafter 823 314 539 528 11 27 Total finance lease payments 1,659 434 870 748 122 32 Less: amounts representing interest (690 ) (255 ) (465 ) (441 ) (24 ) (22 ) Total finance lease liabilities $ 969 $ 179 $ 405 $ 307 $ 98 $ 10 The following table presents future minimum lease payments under finance leases, as reported under the former lease standard. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2019 $ 170 $ 20 $ 45 $ 20 $ 25 $ 2 $ 1 2020 174 20 46 21 25 — 1 2021 177 15 45 20 25 — 1 2022 165 15 45 21 24 — 1 2023 165 15 45 21 24 — 1 Thereafter 577 204 230 209 21 — 27 Minimum annual payments 1,428 289 456 312 144 2 32 Less: amount representing interest (487 ) (180 ) (205 ) (175 ) (30 ) — (22 ) Total $ 941 $ 109 $ 251 $ 137 $ 114 $ 2 $ 10 The following tables contain additional information related to leases. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Classification Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Assets Operating Operating lease ROU assets, net $ 1,658 $ 123 $ 788 $ 387 $ 401 $ 21 $ 57 $ 24 Finance Net property, plant and equipment 926 198 443 308 135 — 7 — Total lease assets $ 2,584 $ 321 $ 1,231 $ 695 $ 536 $ 21 $ 64 $ 24 Liabilities Current Operating Other current liabilities $ 208 $ 27 $ 95 $ 37 $ 58 $ 1 $ 3 $ 4 Finance Current maturities of long-term debt 119 7 24 6 18 — — — Noncurrent Operating Operating lease liabilities 1,432 102 697 354 343 21 55 23 Finance Long-Term Debt 850 172 381 301 80 — 10 — Total lease liabilities $ 2,609 $ 308 $ 1,197 $ 698 $ 499 $ 22 $ 68 $ 27 Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Cash paid for amounts included in the measurement of lease liabilities (a) Operating cash flows from operating leases $ 285 $ 34 $ 131 $ 53 $ 78 $ 2 $ 7 $ 7 Operating cash flows from finance leases 61 15 42 33 9 — 1 — Financing cash flows from finance leases 111 6 21 5 16 1 — — Lease assets obtained in exchange for new lease liabilities (non-cash) Operating (b) $ 194 $ 44 $ 30 $ 30 $ — $ — $ — $ 1 Finance 251 76 175 175 — — — — (a) No amounts were classified as investing cash flows from operating leases for the year ended December 31, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Weighted average remaining lease term (years) Operating leases 11 9 10 12 8 17 18 6 Finance leases 13 19 16 18 11 — 26 — Weighted average discount rate (a) Operating leases 3.9 % 3.5 % 3.8 % 3.9 % 3.8 % 4.2 % 4.1 % 3.6 % Finance leases 8.1 % 11.8 % 11.9 % 12.4 % 8.3 % — % 11.9 % — % (a) The discount rate is calculated using the rate implicit in a lease if it is readily determinable. Generally, the rate used by the lessor is not provided to Duke Energy and in these cases the incremental borrowing rate is used. Duke Energy will typically use its fully collateralized incremental borrowing rate as of the commencement date to calculate and record the lease. The incremental borrowing rate is influenced by the lessee’s credit rating and lease term and as such may differ for individual leases, embedded leases or portfolios of leased assets.

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt and Credit Facilities	DEBT AND CREDIT FACILITIES Summary of Debt and Related Terms The following tables summarize outstanding debt. December 31, 2019 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unsecured debt, maturing 2020-2078 4.02 % $ 22,477 $ 1,150 $ 3,650 $ 700 $ 350 $ 1,110 $ 405 $ 2,399 Secured debt, maturing 2020-2052 3.30 % 4,537 544 1,722 335 1,387 — — — First mortgage bonds, maturing 2020-2049 (a) 4.13 % 27,977 9,557 13,800 7,575 6,225 1,449 3,169 — Finance leases, maturing 2022-2051 (b) 6.60 % 969 179 405 307 98 — 10 — Tax-exempt bonds, maturing 2022-2041 (c) 2.90 % 730 243 48 48 — 77 362 — Notes payable and commercial paper (d) 1.98 % 3,588 — — — — — — — Money pool/intercompany borrowings — 329 1,970 216 — 337 180 476 Fair value hedge carrying value adjustment 5 5 — — — — — — Unamortized debt discount and premium, net (e) 1,294 (23 ) (29 ) (17 ) (11 ) (30 ) (19 ) (2 ) Unamortized debt issuance costs (f) (316 ) (55 ) (111 ) (40 ) (62 ) (12 ) (20 ) (13 ) Total debt 3.92 % $ 61,261 $ 11,929 $ 21,455 $ 9,124 $ 7,987 $ 2,931 $ 4,087 $ 2,860 Short-term notes payable and commercial paper (3,135 ) — — — — — — — Short-term money pool/intercompany borrowings — (29 ) (1,821 ) (66 ) — (312 ) (30 ) (476 ) Current maturities of long-term debt (g) (3,141 ) (458 ) (1,577 ) (1,006 ) (571 ) — (503 ) — Total long-term debt (g) $ 54,985 $ 11,442 $ 18,057 $ 8,052 $ 7,416 $ 2,619 $ 3,554 $ 2,384 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $44 million and $419 million of finance lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to PPAs that are not accounted for as finance leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds, letters of credit or the Master Credit Facility. (d) Includes $625 million classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy's commercial paper program was 14 days. (e) Duke Energy includes $1,275 million and $137 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively. (f) Duke Energy includes $37 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (g) Refer to Note 18 for additional information on amounts from consolidated VIEs. December 31, 2018 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unsecured debt, maturing 2019-2078 4.26 % $ 20,955 $ 1,150 $ 3,800 $ 50 $ 350 $ 1,000 $ 408 $ 2,150 Secured debt, maturing 2020-2037 3.69 % 4,297 450 1,703 300 1,403 — — — First mortgage bonds, maturing 2019-2048 (a) 4.32 % 25,628 8,759 13,100 7,574 5,526 1,099 2,670 — Finance leases, maturing 2019-2051 (b) 5.06 % 941 109 251 137 114 2 10 — Tax-exempt bonds, maturing 2019-2041 (c) 3.40 % 941 243 48 48 — 77 572 — Notes payable and commercial paper (d) 2.73 % 4,035 — — — — — — — Money pool/intercompany borrowings — 739 1,385 444 108 299 317 198 Fair value hedge carrying value adjustment 5 5 — — — — — — Unamortized debt discount and premium, net (e) 1,434 (23 ) (29 ) (15 ) (11 ) (31 ) (8 ) (1 ) Unamortized debt issuance costs (f) (297 ) (54 ) (112 ) (40 ) (61 ) (7 ) (20 ) (11 ) Total debt 4.13 % $ 57,939 $ 11,378 $ 20,146 $ 8,498 $ 7,429 $ 2,439 $ 3,949 $ 2,336 Short-term notes payable and commercial paper (3,410 ) — — — — — — — Short-term money pool/intercompany borrowings — (439 ) (1,235 ) (294 ) (108 ) (274 ) (167 ) (198 ) Current maturities of long-term debt (g) (3,406 ) (6 ) (1,672 ) (603 ) (270 ) (551 ) (63 ) (350 ) Total long-term debt (g) $ 51,123 $ 10,933 $ 17,239 $ 7,601 $ 7,051 $ 1,614 $ 3,719 $ 1,788 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $63 million and $531 million of finance lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to PPAs that are not accounted for as finance leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds, letters of credit or the Master Credit Facility. (d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy's commercial paper programs was 16 days. (e) Duke Energy includes $1,380 million and $156 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively. (f) Duke Energy includes $41 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (g) Refer to Note 18 for additional information on amounts from consolidated VIEs. Current Maturities of Long-Term Debt The following table shows the significant components of Current maturities of Long-Term Debt on the Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate December 31, 2019 Unsecured Debt Duke Energy (Parent) June 2020 2.100 % $ 330 Duke Energy Progress December 2020 2.510 % (a) 700 First Mortgage Bonds Duke Energy Florida January 2020 1.850 % 250 Duke Energy Florida April 2020 4.550 % 250 Duke Energy Carolinas June 2020 4.300 % 450 Duke Energy Indiana July 2020 3.750 % 500 Duke Energy Progress September 2020 2.065 % (a) 300 Other (b) 361 Current maturities of long-term debt $ 3,141 (a) Debt has a floating interest rate. (b) Includes finance lease obligations, amortizing debt and small bullet maturities. Maturities and Call Options The following table shows the annual maturities of long-term debt for the next five years and thereafter. Amounts presented exclude short-term notes payable, commercial paper and money pool borrowings and debt issuance costs for the Subsidiary Registrants. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy (a) Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 3,141 $ 458 $ 1,578 $ 1,006 $ 572 — $ 503 $ — 2021 5,053 504 2,257 932 825 50 70 160 2022 4,334 830 1,048 508 90 — 94 — 2023 3,112 1,006 398 319 79 325 3 45 2024 1,965 306 227 160 67 25 154 40 Thereafter 39,542 8,875 14,267 6,190 6,427 2,261 3,272 2,155 Total long-term debt, including current maturities $ 57,147 $ 11,979 $ 19,775 $ 9,115 $ 8,060 $ 2,661 $ 4,096 $ 2,400 (a) Excludes $1,448 million in purchase accounting adjustments related to the Progress Energy merger and the Piedmont acquisition. The Duke Energy Registrants have the ability under certain debt facilities to call and repay the obligation prior to its scheduled maturity. Therefore, the actual timing of future cash repayments could be materially different than as presented above. Short-Term Obligations Classified as Long-Term Debt Tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder and certain commercial paper issuances and money pool borrowings are classified as Long-Term Debt on the Consolidated Balance Sheets. These tax-exempt bonds, commercial paper issuances and money pool borrowings, which are short-term obligations by nature, are classified as long-term due to Duke Energy’s intent and ability to utilize such borrowings as long-term financing. As Duke Energy’s Master Credit Facility and other bilateral letter of credit agreements have non-cancelable terms in excess of one year as of the balance sheet date, Duke Energy has the ability to refinance these short-term obligations on a long-term basis. The following tables show short-term obligations classified as long-term debt. December 31, 2019 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 312 $ — $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 937 $ 300 $ 150 $ 52 $ 435 December 31, 2018 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 312 $ — $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 937 $ 300 $ 150 $ 52 $ 435 (a) Progress Energy amounts are equal to Duke Energy Progress amounts. Summary of Significant Debt Issuances The following tables summarize significant debt issuances (in millions). Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Unsecured Debt March 2019 (a) Mar 2022 2.538 % (b) $ 300 $ 300 $ — $ — $ — $ — $ — $ — March 2019 (a) Mar 2022 3.227 % 300 300 — — — — — — May 2019 (e) Jun 2029 3.500 % 600 — — — — — — 600 June 2019 (a) Jun 2029 3.400 % 600 600 — — — — — — June 2019 (a) Jun 2049 4.200 % 600 600 — — — — — — July 2019 (g) Jul 2049 4.320 % 40 — — — — 40 — — September 2019 (g) Oct 2025 3.230 % 95 — — — — 95 — — September 2019 (g) Oct 2029 3.560 % 75 — — — — 75 — — November 2019 (h) Nov 2021 2.167 % (b) 200 — — — 200 — — — First Mortgage Bonds January 2019 (c) Feb 2029 3.650 % 400 — — — — 400 — — January 2019 (c) Feb 2049 4.300 % 400 — — — — 400 — — March 2019 (d) Mar 2029 3.450 % 600 — — 600 — — — — August 2019 (a) Aug 2029 2.450 % 450 — 450 — — — — — August 2019 (a) Aug 2049 3.200 % 350 — 350 — — — — — September 2019 (f) Oct 2049 3.250 % 500 — — — — — 500 — November 2019 (i) Dec 2029 2.500 % 700 — — — 700 — — — Total issuances $ 6,210 $ 1,800 $ 800 $ 600 $ 900 $ 1,010 $ 500 $ 600 (a) Debt issued to pay down short-term debt and for general corporate purposes. (b) Debt issuance has a floating interest rate. (c) Debt issued to repay at maturity $450 million first mortgage bonds due April 2019, pay down short-term debt and for general corporate purposes. (d) Debt issued to fund eligible green energy projects in the Carolinas. (e) Debt issued to repay in full the outstanding $350 million Piedmont unsecured term loan due September 2019, pay down short-term debt and for general corporate purposes. (f) Debt issued to retire $150 million of pollution control bonds, pay down short-term debt and for general corporate purposes. (g) Debt issued to repay at maturity $100 million debentures due October 2019, pay down short-term debt and for general corporate purposes. (h) Debt issued to fund storm restoration costs and for general corporate purposes. (i) Debt issued to reimburse the payment of existing and new Eligible Green Expenditures in Florida. In January 2020, Duke Energy Carolinas closed and funded $900 million of first mortgage bonds of which $500 million carry a fixed interest rate of 2.45% and mature February 2030 and $400 million carry a fixed interest rate of 3.20% and mature August 2049. The proceeds will be used to repay at maturity $450 million , 4.30% debentures maturing June 2020, and for general corporate purposes. Year Ended December 31, 2018 Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Unsecured Debt March 2018 (a) April 2025 3.950 % $ 250 $ 250 $ — $ — $ — May 2018 (b) May 2021 3.114 % 500 500 — — — September 2018 (c) September 2078 5.625 % 500 500 — — — First Mortgage Bonds March 2018 (d) March 2023 3.050 % 500 — 500 — — March 2018 (d) March 2048 3.950 % 500 — 500 — — June 2018 (e) July 2028 3.800 % 600 — — — 600 June 2018 (e) July 2048 4.200 % 400 — — — 400 August 2018 (f) September 2023 3.375 % 300 — — 300 — August 2018 (f) September 2028 3.700 % 500 — — 500 — November 2018 (g) May 2022 3.350 % 350 — 350 — — November 2018 (g) November 2028 3.950 % 650 — 650 — — Total issuances $ 5,050 $ 1,250 $ 2,000 $ 800 $ 1,000 (a) Debt issued to pay down short-term debt. (b) Debt issued to pay down short-term debt. Debt issuance has a floating debt rate. (c) Callable after September 2023 at par. Junior subordinated hybrid debt issued to pay down short-term debt and for general corporate purposes. (d) Debt issued to repay at maturity a $300 million first mortgage bond due April 2018, pay down intercompany short-term debt and for general corporate purposes. (e) Debt issued to repay a portion of intercompany short-term debt under the money pool borrowing arrangement and for general corporate purposes. (f) Debt issued to repay short-term debt and for general corporate purposes. (g) Debt issued to fund eligible green energy projects, including zero-carbon solar and energy storage, in the Carolinas. Available Credit Facilities In March 2019, Duke Energy amended its existing $8 billion Master Credit Facility to extend the termination date to March 2024. The Duke Energy Registrants, excluding Progress Energy, have borrowing capacity under the Master Credit Facility up to a specified sublimit for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower. The amount available under the Master Credit Facility has been reduced to backstop issuances of commercial paper, certain letters of credit and variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder. Duke Energy Carolinas and Duke Energy Progress are also required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet obligations under plea agreements reached with the U.S. Department of Justice in 2015 related to violations at North Carolina facilities with ash basins. The table below includes the current borrowing sublimits and available capacity under these credit facilities. December 31, 2019 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Facility size (a) $ 8,000 $ 2,650 $ 1,500 $ 1,250 $ 800 $ 600 $ 600 $ 600 Reduction to backstop issuances Commercial paper (b) (2,537 ) (1,119 ) (325 ) (207 ) — (296 ) (176 ) (414 ) Outstanding letters of credit (50 ) (42 ) (4 ) (2 ) — — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity $ 4,832 $ 1,489 $ 921 $ 791 $ 800 $ 304 $ 343 $ 184 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Consolidated Balance Sheets. Three-Year Revolving Credit Facility Duke Energy (Parent) has a $1 billion revolving credit facility. The facility had an initial termination date of June 2020, but in May 2019, Duke Energy extended the termination date of the facility to May 2022. Borrowings under this facility will be used for general corporate purposes. As of December 31, 2019 , $500 million has been drawn under this facility. This balance is classified as Long-term debt on Duke Energy's Consolidated Balance Sheets. Any undrawn commitments can be drawn, and borrowings can be prepaid, at any time throughout the term of the facility. The terms and conditions of the facility are generally consistent with those governing Duke Energy's Master Credit Facility. Duke Energy Progress Term Loan Facility In December 2018, Duke Energy Progress entered into a two-year term loan facility with commitments totaling $700 million . Borrowings under the facility were used to pay storm-related costs, pay down commercial paper and to partially finance an upcoming bond maturity. As of December 31, 2019 , the entire $700 million has been drawn under the term loan. This balance is classified as Current maturities of long-term debt on Duke Energy Progress' Consolidated Balance Sheets. Piedmont Term Loan Facility In May 2019, the $350 million Piedmont term loan was paid off in full with proceeds from the $600 million Piedmont debt offering. Other Debt Matters In September 2019, Duke Energy filed a Form S-3 with the SEC. Under this Form S-3, which is uncapped, the Duke Energy Registrants, excluding Progress Energy, may issue debt and other securities in the future at amounts, prices and with terms to be determined at the time of future offerings. The registration statement was filed to replace a similar prior filing upon expiration of its three-year term and also allows for the issuance of common and preferred stock by Duke Energy. The expired Form S-3 was amended in March 2019, to allow Duke Energy to issue preferred stock. Duke Energy has an effective Form S-3 with the SEC to sell up to $3 billion of variable denomination floating-rate demand notes, called PremierNotes. The Form S-3 states that no more than $1.5 billion of the notes will be outstanding at any particular time. The notes are offered on a continuous basis and bear interest at a floating rate per annum determined by the Duke Energy PremierNotes Committee, or its designee, on a weekly basis. The interest rate payable on notes held by an investor may vary based on the principal amount of the investment. The notes have no stated maturity date, are non-transferable and may be redeemed in whole or in part by Duke Energy or at the investor’s option at any time. The balance as of December 31, 2019 , and 2018 , was $1,049 million and $1,010 million , respectively. The notes are short-term debt obligations of Duke Energy and are reflected as Notes payable and commercial paper on Duke Energy’s Consolidated Balance Sheets. Money Pool The Subsidiary Registrants, excluding Progress Energy, are eligible to receive support for their short-term borrowing needs through participation with Duke Energy and certain of its subsidiaries in a money pool arrangement. Under this arrangement, those companies with short-term funds may provide short-term loans to affiliates participating in this arrangement. The money pool is structured such that the Subsidiary Registrants, excluding Progress Energy, separately manage their cash needs and working capital requirements. Accordingly, there is no net settlement of receivables and payables between money pool participants. Duke Energy (Parent), may loan funds to its participating subsidiaries, but may not borrow funds through the money pool. Accordingly, as the money pool activity is between Duke Energy and its wholly owned subsidiaries, all money pool balances are eliminated within Duke Energy’s Consolidated Balance Sheets. Money pool receivable balances are reflected within Notes receivable from affiliated companies on the Subsidiary Registrants’ Consolidated Balance Sheets. Money pool payable balances are reflected within either Notes payable to affiliated companies or Long-Term Debt Payable to Affiliated Companies on the Subsidiary Registrants’ Consolidated Balance Sheets. Restrictive Debt Covenants The Duke Energy Registrants’ debt and credit agreements contain various financial and other covenants. Duke Energy's Master Credit Facility contains a covenant requiring the debt-to-total capitalization ratio not to exceed 65% for each borrower, excluding Piedmont, and 70% for Piedmont. Failure to meet those covenants beyond applicable grace periods could result in accelerated due dates and/or termination of the agreements. As of December 31, 2019 , each of the Duke Energy Registrants was in compliance with all covenants related to their debt agreements. In addition, some credit agreements may allow for acceleration of payments or termination of the agreements due to nonpayment, or acceleration of other significant indebtedness of the borrower or some of its subsidiaries. None of the debt or credit agreements contain material adverse change clauses. Other Loans As of December 31, 2019 , and 2018 , Duke Energy had loans outstanding of $777 million , including $36 million at Duke Energy Progress and $741 million , including $37 million at Duke Energy Progress, respectively, against the cash surrender value of life insurance policies it owns on the lives of its executives. The amounts outstanding were carried as a reduction of the related cash surrender value that is included in Other within Other Noncurrent Assets on the Consolidated Balance Sheets.

Guarantees and Indemnifications

Guarantees and Indemnifications	12 Months Ended
	Dec. 31, 2019
Guarantees [Abstract]
Guarantees and Indemnifications	GUARANTEES AND INDEMNIFICATIONS Duke Energy has various financial and performance guarantees and indemnifications with non-consolidated entities, which are issued in the normal course of business. As discussed below, these contracts include performance guarantees, standby letters of credit, debt guarantees and indemnifications. Duke Energy enters into these arrangements to facilitate commercial transactions with third parties by enhancing the value of the transaction to the third party. At December 31, 2019 , Duke Energy does not believe conditions are likely for significant performance under these guarantees. To the extent liabilities are incurred as a result of the activities covered by the guarantees, such liabilities are included on the accompanying Consolidated Balance Sheets. On January 2, 2007, Duke Energy completed the spin-off of its previously wholly-owned natural gas businesses to shareholders. Guarantees issued by Duke Energy or its affiliates, or assigned to Duke Energy prior to the spin-off, remained with Duke Energy subsequent to the spin-off. Guarantees issued by Spectra Capital or its affiliates prior to the spin-off remained with Spectra Capital subsequent to the spin-off, except for guarantees that were later assigned to Duke Energy. Duke Energy has indemnified Spectra Capital against any losses incurred under certain of the guarantee obligations that remain with Spectra Capital. At December 31, 2019 , the maximum potential amount of future payments associated with these guarantees were $65 million , the majority of which expires by 2028. In October 2017, ACP executed a $3.4 billion revolving credit facility with a stated maturity date of October 2021. Duke Energy entered into a guarantee agreement to support its share of the ACP revolving credit facility. Duke Energy's maximum exposure to loss under the terms of the guarantee is $827 million as of December 31, 2019 . This amount represents 47% of the outstanding borrowings under the credit facility. In addition to the Spectra Capital and ACP revolving credit facility guarantees above, Duke Energy has issued performance guarantees to customers and other third parties that guarantee the payment and performance of other parties, including certain non-wholly owned entities, as well as guarantees of debt of certain non-consolidated entities. If such entities were to default on payments or performance, Duke Energy would be required under the guarantees to make payments on the obligations of these entities. The maximum potential amount of future payments required under these guarantees as of December 31, 2019 , was $128 million , of which, $114 million expire between 2020 and 2030, with the remaining performance guarantees having no contractual expiration. Additionally, certain guarantees have uncapped maximum potential payments; however, Duke Energy does not believe these guarantees will have a material effect on its results of operations, cash flows or financial position. Duke Energy uses bank-issued standby letters of credit to secure the performance of wholly owned and non-wholly owned entities to a third party or customer. Under these arrangements, Duke Energy has payment obligations to the issuing bank that are triggered by a draw by the third party or customer due to the failure of the wholly owned or non-wholly owned entity to perform according to the terms of its underlying contract. At December 31, 2019 , Duke Energy had issued a total of $634 million in letters of credit, which expire between 2020 and 2022. The unused amount under these letters of credit was $81 million . Duke Energy recognized $23 million as of December 31, 2019 , and 2018

Joint Ownership of Generating a

Joint Ownership of Generating and Transmission Facilities	12 Months Ended
	Dec. 31, 2019
Joint Ownership Of Generating And Transmission Facilities [Abstract]
Joint Ownership of Generating and Transmission Facilities	JOINT OWNERSHIP OF GENERATING AND TRANSMISSION FACILITIES The Duke Energy Registrants maintain ownership interests in certain jointly owned generating and transmission facilities. The Duke Energy Registrants are entitled to a share of the generating capacity and output of each unit equal to their respective ownership interests. The Duke Energy Registrants pay their ownership share of additional construction costs, fuel inventory purchases and operating expenses. The Duke Energy Registrants share of revenues and operating costs of the jointly owned facilities is included within the corresponding line in the Consolidated Statements of Operations. Each participant in the jointly owned facilities must provide its own financing. The following table presents the Duke Energy Registrants' interest of jointly owned plant or facilities and amounts included on the Consolidated Balance Sheets. All facilities are operated by the Duke Energy Registrants and are included in the Electric Utilities and Infrastructure segment. December 31, 2019 Construction Ownership Property, Plant Accumulated Work in (in millions except for ownership interest) Interest and Equipment Depreciation Progress Duke Energy Carolinas Catawba (units 1 and 2) (a) 19.25 % $ 1,011 $ 510 $ 21 W.S. Lee CC (b) 87.27 % 609 32 1 Duke Energy Indiana Gibson (unit 5) (c) 50.05 % 410 183 3 Vermillion (d) 62.50 % 172 119 — Transmission and local facilities (c) Various 5,421 1,436 172 (a) Jointly owned with North Carolina Municipal Power Agency Number 1, NCEMC and PMPA. (b) Jointly owned with NCEMC. (c) Jointly owned with WVPA and IMPA. (d) Jointly owned with WVPA.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS Duke Energy records an ARO when it has a legal obligation to incur retirement costs associated with the retirement of a long-lived asset and the obligation can be reasonably estimated. Certain assets of the Duke Energy Registrants have an indeterminate life, such as transmission and distribution facilities, and thus the fair value of the retirement obligation is not reasonably estimable. A liability for these AROs will be recorded when a fair value is determinable. The Duke Energy Registrants’ regulated operations accrue costs of removal for property that does not have an associated legal retirement obligation based on regulatory orders from state commissions. These costs of removal are recorded as a regulatory liability in accordance with regulatory accounting treatment. The Duke Energy Registrants do not accrue the estimated cost of removal for any nonregulated assets. See Note 4 for the estimated cost of removal for assets without an associated legal retirement obligation, which are included in Regulatory liabilities on the Consolidated Balance Sheets. The following table presents the AROs recorded on the Consolidated Balance Sheets. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Decommissioning of nuclear power facilities (a) $ 6,633 $ 2,551 $ 4,028 $ 3,499 $ 529 $ — $ — $ — Closure of ash impoundments 6,333 3,118 2,368 2,352 16 41 805 — Other 352 65 75 42 33 39 27 17 Total asset retirement obligation $ 13,318 $ 5,734 $ 6,471 $ 5,893 $ 578 $ 80 $ 832 $ 17 Less: current portion 881 206 485 485 — 1 189 — Total noncurrent asset retirement obligation $ 12,437 $ 5,528 $ 5,986 $ 5,408 $ 578 $ 79 $ 643 $ 17 (a) Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy. Nuclear Decommissioning Liability AROs related to nuclear decommissioning are based on site-specific cost studies. The NCUC, PSCSC and FPSC require updated cost estimates for decommissioning nuclear plants every five years. The following table summarizes information about the most recent site-specific nuclear decommissioning cost studies. Decommissioning costs are stated in 2018 or 2019 dollars, depending on the year of the cost study, and include costs to decommission plant components not subject to radioactive contamination. Annual Funding Decommissioning (in millions) Requirement (a) Costs (a) Year of Cost Study Duke Energy $ 24 $ 9,152 2018 and 2019 Duke Energy Carolinas (b)(c) — 4,365 2018 Duke Energy Progress (d) 24 4,181 2019 Duke Energy Florida (e) — 606 2019 (a) Amounts for Progress Energy equal the sum of Duke Energy Progress and Duke Energy Florida. (b) Decommissioning cost for Duke Energy Carolinas reflects its ownership interest in jointly owned reactors. Other joint owners are responsible for decommissioning costs related to their interest in the reactors. (c) Duke Energy Carolinas' site-specific nuclear decommissioning cost study completed in 2018 was filed with the NCUC and PSCSC in 2019. A new funding study was also completed and filed with the NCUC and PSCSC in 2019. (d) Duke Energy Progress' site-specific nuclear decommissioning cost study completed in 2019 is expected to be filed with the NCUC and PSCSC during the first quarter 2020. Duke Energy Progress will also complete a new funding study, which will be completed and filed with the NCUC and PSCSC in July 2020. (e) During 2019, Duke Energy Florida reached an agreement to transfer decommissioning work for Crystal River Unit 3 to a third party. The agreement requires regulatory approval from the NRC and the FPSC. See Note 4 for more information. Nuclear Decommissioning Trust Funds Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida each maintain NDTFs that are intended to pay for the decommissioning costs of their respective nuclear power plants. The NDTF investments are managed and invested in accordance with applicable requirements of various regulatory bodies including the NRC, FERC, NCUC, PSCSC, FPSC and the IRS. Use of the NDTF investments is restricted to nuclear decommissioning activities including license termination, spent fuel and site restoration. The license termination and spent fuel obligations relate to contaminated decommissioning and are recorded as AROs. The site restoration obligation relates to non-contaminated decommissioning and is recorded to cost of removal within Regulatory liabilities on the Consolidated Balance Sheets. The following table presents the fair value of NDTF assets legally restricted for purposes of settling AROs associated with nuclear decommissioning. Duke Energy Florida is actively decommissioning Crystal River Unit 3 and was granted an exemption from the NRC, which allows for use of the NDTF for all aspects of nuclear decommissioning. The entire balance of Duke Energy Florida's NDTF may be applied toward license termination, spent fuel and site restoration costs incurred to decommission Crystal River Unit 3 and is excluded from the table below. See Note 17 for additional information related to the fair value of the Duke Energy Registrants' NDTFs. December 31, (in millions) 2019 2018 Duke Energy $ 6,766 $ 5,579 Duke Energy Carolinas 3,837 3,133 Duke Energy Progress 2,929 2,446 Nuclear Operating Licenses Operating licenses for nuclear units are potentially subject to extension. The following table includes the current expiration of nuclear operating licenses. Unit Year of Expiration Duke Energy Carolinas Catawba Units 1 and 2 2043 McGuire Unit 1 2041 McGuire Unit 2 2043 Oconee Units 1 and 2 2033 Oconee Unit 3 2034 Duke Energy Progress Brunswick Unit 1 2036 Brunswick Unit 2 2034 Harris 2046 Robinson 2030 The NRC has acknowledged permanent cessation of operation and permanent removal of fuel from the reactor vessel at Crystal River Unit 3. Therefore, the license no longer authorizes operation of the reactor. In 2019, Duke Energy Florida entered into an agreement for the accelerated decommissioning of Crystal River Unit 3. The agreement is subject to the approval of the NRC and FPSC. See Note 4 for more information. Closure of Ash Impoundments The Duke Energy Registrants are subject to state and federal regulations covering the closure of coal ash impoundments, including the EPA CCR rule and the Coal Ash Act, and other agreements. AROs recorded on the Duke Energy Registrants' Consolidated Balance Sheets include the legal obligation for closure of coal ash basins and the disposal of related ash as a result of these regulations and agreements. The ARO amount recorded on the Consolidated Balance Sheets is based upon estimated closure costs for impacted ash impoundments. The amount recorded represents the discounted cash flows for estimated closure costs based upon specific closure plans. Actual costs to be incurred will be dependent upon factors that vary from site to site. The most significant factors are the method and time frame of closure at the individual sites. Closure methods considered include removing the water from ash basins, consolidating material as necessary and capping the ash with a synthetic barrier, excavating and relocating the ash to a lined structural fill or lined landfill or recycling the ash for concrete or some other beneficial use. The ultimate method and timetable for closure will be in compliance with standards set by federal and state regulations and other agreements. The ARO amount will be adjusted as additional information is gained through the closure and post-closure process, including acceptance and approval of compliance approaches, which may change management assumptions, and may result in a material change to the balance. See ARO Liability Rollforward section below for information on revisions made to the coal ash liability during 2019 and 2018 . Asset retirement costs associated with the AROs for operating plants and retired plants are included in Net property, plant and equipment and Regulatory assets, respectively, on the Consolidated Balance Sheets. See Note 4 for additional information on Regulatory assets related to AROs. Cost recovery for future expenditures will be pursued through the normal ratemaking process with federal and state utility commissions, which permit recovery of necessary and prudently incurred costs associated with Duke Energy’s regulated operations. See Note 4 for additional information on recovery of coal ash costs. ARO Liability Rollforward The following tables present changes in the liability associated with AROs. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at December 31, 2017 $ 10,175 $ 3,610 $ 5,414 $ 4,673 $ 742 $ 84 $ 781 $ 15 Accretion expense (a) 427 179 225 196 29 4 29 1 Liabilities settled (b) (638 ) (281 ) (272 ) (227 ) (45 ) (5 ) (79 ) — Liabilities incurred in the current year (c) 39 8 5 — 5 — 25 — Revisions in estimates of cash flows 464 433 39 178 (140 ) 10 (34 ) 3 Balance at December 31, 2018 10,467 3,949 5,411 4,820 591 93 722 19 Accretion expense (a) 508 235 252 227 25 3 28 1 Liabilities settled (b) (895 ) (329 ) (499 ) (460 ) (39 ) (12 ) (54 ) — Liabilities incurred in the current year 25 18 7 — 7 — — — Revisions in estimates of cash flows (d) 3,213 1,861 1,300 1,306 (6 ) (4 ) 136 (3 ) Balance at December 31, 2019 $ 13,318 $ 5,734 $ 6,471 $ 5,893 $ 578 $ 80 $ 832 $ 17 (a) Substantially all accretion expense for the years ended December 31, 2019 , and 2018 , relates to Duke Energy’s regulated operations and has been deferred in accordance with regulatory accounting treatment. (b) Amounts primarily relate to ash impoundment closures and nuclear decommissioning of Crystal River Unit 3. (c) Amounts primarily relate to AROs recorded as a result of state agency closure requirements at Duke Energy Indiana. (d) Amounts primarily relate to increases in closure estimates for certain ash impoundments as a result of the NCDEQ's April 1 Order and the related settlement agreement dated December 31, 2019. See Note 5 for more information. The amount recorded in the fourth quarter of 2019 for coal ash closures as a result of the settlement was not material.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants. December 31, 2019 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Land $ 2,091 $ 520 $ 884 $ 449 $ 435 $ 150 $ 117 $ 388 Plant – Regulated Electric generation, distribution and transmission 15-100 111,739 42,723 48,142 30,018 18,124 5,838 15,032 — Natural gas transmission and distribution 4-73 9,839 — — — — 2,892 — 6,947 Other buildings and improvements 23-90 1,810 714 401 162 239 269 278 148 Plant – Nonregulated Electric generation, distribution and transmission 5-30 5,103 — — — — — — — Other buildings and improvements 25-35 488 — — — — — — — Nuclear fuel 3,253 1,891 1,362 1,362 — — — — Equipment 3-25 2,313 546 665 452 213 319 205 128 Construction in process 6,102 1,389 2,149 1,114 1,035 504 381 531 Other 2-40 4,916 1,139 1,467 1,046 411 269 292 304 Total property, plant and equipment (a)(e) 147,654 48,922 55,070 34,603 20,457 10,241 16,305 8,446 Total accumulated depreciation – regulated (b)(c) (43,419 ) (16,525 ) (17,159 ) (11,915 ) (5,236 ) (2,843 ) (5,233 ) (1,681 ) Total accumulated depreciation – nonregulated (d)(e) (2,354 ) — — — — — — — Generation facilities to be retired, net 246 — 246 246 — — — — Total net property, plant and equipment $ 102,127 $ 32,397 $ 38,157 $ 22,934 $ 15,221 $ 7,398 $ 11,072 $ 6,765 (a) Includes finance leases of $952 million , $211 million , $443 million , $308 million , $135 million and $10 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $143 million , $17 million and $126 million , respectively, of accumulated amortization of finance leases. (b) Includes $1,807 million , $1,082 million , $725 million and $725 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of finance leases of $6 million , $13 million and $3 million at Duke Energy, Duke Energy Carolinas and Duke Energy Indiana, respectively. (d) Includes accumulated amortization of finance leases of $20 million at Duke Energy. (e) Includes gross property, plant and equipment cost of consolidated VIEs of $5,747 million and accumulated depreciation of consolidated VIEs of $1,041 million at Duke Energy. During the year ended December 31, 2019, Duke Energy evaluated recoverability of the wind and solar generation assets included in the minority interest sale as a result of the portfolio fair value of consideration received being less than the carrying value of the assets and determined the assets were all recoverable. Additionally, in 2019, Duke Energy evaluated recoverability of its renewable merchant plants principally located in the Electric Reliability Council of Texas West market due to declining market pricing and declining long-term forecasted energy prices, primarily driven by lower forecasted natural gas prices. Duke Energy determined that the assets were not impaired because the carrying value of $160 million approximates the aggregate estimated future cash flows. A continued decline in energy market pricing would likely result in a future impairment. December 31, 2018 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Land $ 2,072 $ 472 $ 868 $ 445 $ 423 $ 136 $ 116 $ 448 Plant – Regulated Electric generation, distribution and transmission 15-100 100,706 38,468 42,760 26,147 16,613 5,182 14,292 — Natural gas transmission and distribution 12-80 8,808 — — — — 2,719 — 6,089 Other buildings and improvements 24-90 1,966 681 636 295 341 270 253 126 Plant – Nonregulated Electric generation, distribution and transmission 5-30 4,410 — — — — — — — Other buildings and improvements 25-35 494 — — — — — — — Nuclear fuel 3,460 1,898 1,562 1,562 — — — — Equipment 3-55 2,141 467 565 399 166 384 178 141 Construction in process 5,726 1,678 2,515 1,659 856 412 325 382 Other 3-40 4,675 1,077 1,354 952 393 257 279 300 Total property, plant and equipment (a)(d) 134,458 44,741 50,260 31,459 18,792 9,360 15,443 7,486 Total accumulated depreciation – regulated (b)(c)(d) (41,079 ) (15,496 ) (16,398 ) (11,423 ) (4,968 ) (2,717 ) (4,914 ) (1,575 ) Total accumulated depreciation – nonregulated (c)(d) (2,047 ) — — — — — — — Generation facilities to be retired, net 362 — 362 362 — — — — Total net property, plant and equipment $ 91,694 $ 29,245 $ 34,224 $ 20,398 $ 13,824 $ 6,643 $ 10,529 $ 5,911 (a) Includes finance leases of $1,237 million , $135 million , $257 million , $137 million , $120 million , $73 million and $35 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $131 million , $14 million and $117 million , respectively, of accumulated amortization of finance leases. (b) Includes $1,947 million , $1,087 million , $860 million and $860 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of finance leases of $61 million , $12 million , $20 million and $10 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $4,007 million and accumulated depreciation of consolidated VIEs of $698 million at Duke Energy. During the year ended December 31, 2017, Duke Energy recorded a pretax impairment charge of $69 million on a wholly owned non-contracted wind project. The impairment was recorded within Impairment charges on Duke Energy’s Consolidated Statements of Operations. $58 million of the impairment related to property, plant and equipment and $11 million of the impairment related to a net intangible asset. The charge represents the excess carrying value over the estimated fair value of the project, which was based on a Level 3 Fair Value measurement that was determined from the income approach using discounted cash flows. The impairment was primarily due to the non-contracted wind project being located in a market that has experienced continued declining market pricing during 2017 and declining long-term forecasted energy and capacity prices, driven by low natural gas prices, additional renewable generation placed in service and lack of significant load growth. The following tables present capitalized interest, which includes the debt component of AFUDC. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy $ 159 $ 161 $ 128 Duke Energy Carolinas 30 35 45 Progress Energy 31 51 45 Duke Energy Progress 28 26 21 Duke Energy Florida 3 25 24 Duke Energy Ohio 22 17 10 Duke Energy Indiana 26 27 9 Piedmont 26 17 12

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS GOODWILL Duke Energy The following table presents goodwill by reportable segment for Duke Energy included on Duke Energy's Consolidated Balance Sheets at December 31, 2019 , and 2018 . Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill Balance at December 31, 2018 $ 17,379 $ 1,924 $ 122 $ 19,425 Accumulated impairment charges (a) — — (122 ) (122 ) Goodwill balance at December 31, 2018, adjusted for accumulated impairment charges $ 17,379 $ 1,924 $ — $ 19,303 Goodwill Balance at December 31, 2019 $ 17,379 $ 1,924 $ 122 $ 19,425 Accumulated impairment charges (a) — — (122 ) (122 ) Goodwill balance at December 31, 2019, adjusted for accumulated impairment charges $ 17,379 $ 1,924 $ — $ 19,303 (a) Duke Energy evaluated the recoverability of goodwill during 2018 and 2017 and recorded impairment charges of $93 million and $29 million , respectively, related to the Commercial Renewables reporting unit included in Impairment charges on Duke Energy’s Consolidated Statements of Operations. The fair value of the reporting unit was determined based on the income approach and market approach in 2018 and 2017, respectively. See "Goodwill Impairment Testing" below for the results of the 2019 goodwill impairment test. Duke Energy Ohio Duke Energy Ohio's Goodwill balance of $920 million , allocated $596 million to Electric Utilities and Infrastructure and $324 million to Gas Utilities and Infrastructure, is presented net of accumulated impairment charges of $216 million on the Consolidated Balance Sheets at December 31, 2019 , and 2018 . Progress Energy Progress Energy's Goodwill is included in the Electric Utilities and Infrastructure segment and there are no accumulated impairment charges. Piedmont Piedmont's Goodwill is included in the Gas Utilities and Infrastructure segment and there are no accumulated impairment charges. Goodwill Impairment Testing Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont are required to perform an annual goodwill impairment test as of the same date each year and, accordingly, perform their annual impairment testing of goodwill as of August 31. Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont update their test between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. As the fair value for Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont exceeded their respective carrying values at the date of the annual impairment analysis, no goodwill impairment charges were recorded in 2019 . INTANGIBLE ASSETS The following tables show the carrying amount and accumulated amortization of intangible assets included in Other within Other Noncurrent Assets on the Consolidated Balance Sheets of the Duke Energy Registrants at December 31, 2019 , and 2018 . December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Emission allowances $ 18 $ — $ 5 $ 2 $ 3 $ — $ 12 $ — Renewable energy certificates 172 53 118 118 — 1 — — Natural gas, coal and power contracts 24 — — — — — 24 — Renewable operating and development projects 89 — — — — — — — Other 2 — — — — — — — Total gross carrying amounts 305 53 123 120 3 1 36 — Accumulated amortization – natural gas, coal and power contracts (21 ) — — — — — (21 ) — Accumulated amortization – renewable operating and development projects (34 ) — — — — — — — Accumulated amortization – other (1 ) — — — — — — — Total accumulated amortization (56 ) — — — — — (21 ) — Total intangible assets, net $ 249 $ 53 $ 123 $ 120 $ 3 $ 1 $ 15 $ — December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Emission allowances $ 18 $ — $ 5 $ 2 $ 3 $ — $ 12 $ — Renewable energy certificates 168 46 120 120 — 2 — — Natural gas, coal and power contracts 24 — — — — — 24 — Renewable operating and development projects 84 — — — — — — — Other 6 — — — — — — 3 Total gross carrying amounts 300 46 125 122 3 2 36 3 Accumulated amortization – natural gas, coal and power contracts (20 ) — — — — — (20 ) — Accumulated amortization – renewable operating and development projects (29 ) — — — — — — — Accumulated amortization – other (5 ) — — — — — — (3 ) Total accumulated amortization (54 ) — — — — — (20 ) (3 ) Total intangible assets, net $ 246 $ 46 $ 125 $ 122 $ 3 $ 2 $ 16 $ — See Note 11 for information related to 2017 impairment charge. Amortization Expense Amortization expense amounts for natural gas, coal and power contracts, renewable operating projects and other intangible assets are immaterial for the years ended December 31, 2019 , 2018 and 2017 , and are expected to be immaterial for the next five years as of December 31, 2019 .

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Affiliates	INVESTMENTS IN UNCONSOLIDATED AFFILIATES EQUITY METHOD INVESTMENTS Investments in affiliates that are not controlled by Duke Energy, but over which it has significant influence, are accounted for using the equity method. The following table presents Duke Energy’s investments in unconsolidated affiliates accounted for under the equity method, as well as the respective equity in earnings, by segment. Years Ended December 31, 2019 2018 2017 Equity in Equity in Equity in (in millions) Investments earnings Investments earnings Investments earnings Electric Utilities and Infrastructure $ 122 $ 9 $ 97 $ 6 $ 89 $ 5 Gas Utilities and Infrastructure 1,388 114 1,003 27 763 62 Commercial Renewables 314 (4 ) 201 (1 ) 190 (5 ) Other 112 43 108 51 133 57 Total $ 1,936 $ 162 $ 1,409 $ 83 $ 1,175 $ 119 During the years ended December 31, 2019 , 2018 and 2017 , Duke Energy received distributions from equity investments of $55 million , $108 million and $13 million , respectively, which are included in Other assets within Cash Flows from Operating Activities on the Consolidated Statements of Cash Flows. During the years ended December 31, 2019 , 2018 and 2017 , Duke Energy received distributions from equity investments of $11 million , $137 million and $281 million , respectively, which are included in Return of investment capital within Cash Flows from Investing Activities on the Consolidated Statements of Cash Flows. During the years ended December 31, 2019 , 2018 and 2017 , Piedmont received distributions from equity investments of $1 million , $1 million and $4 million , respectively, which are included in Other assets within Cash Flows from Operating Activities and $4 million , $3 million and $2 million , respectively, which are included within Cash Flows from Investing Activities on the Consolidated Statements of Cash Flows. Significant investments in affiliates accounted for under the equity method are discussed below. Electric Utilities and Infrastructure Duke Energy owns a 50% interest in DATC and in Pioneer, which build, own and operate electric transmission facilities in North America. Gas Utilities and Infrastructure The table below outlines Duke Energy's ownership interests in natural gas pipeline companies and natural gas storage facilities. Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest 2019 2018 Pipeline Investments ACP 47 % $ 1,179 $ 797 Sabal Trail 7.5 % 121 112 (c) Constitution 24 % — 25 Cardinal (a) 21.49 % 9 10 Storage Facilities Pine Needle (a) 45 % 28 13 Hardy Storage (a) 50 % 51 46 Total Investments (b) $ 1,388 $ 1,003 (a) Piedmont owns the Cardinal, Pine Needle and Hardy Storage investments. (b) Duke Energy includes purchase accounting adjustments related to Piedmont. (c) Sabal Trail returned capital of $112 million during the year ended December 31, 2018. In October 2017, Duke Energy entered into a guarantee agreement to support its share of the ACP revolving credit facility. See Note 8 for additional information. As a result of the financing, ACP returned capital of $265 million to Duke Energy. During 2018 and 2019, ACP received several adverse court rulings as described in Note 4 . As a result, Duke Energy evaluated this investment for impairment and determined that fair value approximated carrying value and therefore no impairment was necessary. For regulatory matters and other information on the ACP, Sabal Trail and Constitution investments, see Notes 4 and 18 . Commercial Renewables DS Cornerstone, LLC, which owns wind farm projects in the U.S. was part of a sale of minority interest in a certain portion of renewable assets to John Hancock in 2019. See Note 2 for more information on the sale. Prior to the sale, Duke Energy had a 50% interest in DS Cornerstone, LLC. After the sale, Duke Energy has a 26% interest in the investment. In 2019, Duke Energy acquired a majority ownership in a portfolio of distributed fuel cell projects from Bloom Energy Corporation. Duke Energy is not the primary beneficiary of the assets within the portfolio and does not consolidate the assets in the portfolio. Impairment of Equity Method Investments Duke Energy recorded OTTIs of the Constitution investment within Equity in earnings of unconsolidated affiliates on Duke Energy's Consolidated Statements of Operations of $25 million and $55 million for the years ended December 31, 2019, and 2018, respectively. The current year charge resulted in the full write-down of Duke Energy's investment in Constitution. The impairments were primarily due to the continued delay in resolving project uncertainty through the courts and regulatory bodies, as well as recent pricing concerns between the customers and owners. For additional information on the Constitution investment, see Note 4 . Other Duke Energy owns a 17.5% indirect interest in NMC, which owns and operates a methanol and MTBE business in Jubail, Saudi Arabia. Duke Energy's economic ownership interest decreased from 25% to 17.5% with the successful startup of NMC's polyacetal production facility in 2017. Duke Energy retains 25% of the board representation and voting rights of NMC.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Subsidiary Registrants engage in related party transactions in accordance with the applicable state and federal commission regulations. Refer to the Consolidated Balance Sheets of the Subsidiary Registrants for balances due to or due from related parties. Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 841 $ 985 $ 858 Indemnification coverages (b) 20 22 23 Joint Dispatch Agreement (JDA) revenue (c) 60 84 49 JDA expense (c) 186 207 145 Intercompany natural gas purchases (d) 15 15 9 Progress Energy Corporate governance and shared service expenses (a) $ 778 $ 906 $ 736 Indemnification coverages (b) 37 34 38 JDA revenue (c) 186 207 145 JDA expense (c) 60 84 49 Intercompany natural gas purchases (d) 76 78 77 Duke Energy Progress Corporate governance and shared service expenses (a) $ 462 $ 577 $ 438 Indemnification coverages (b) 15 13 15 JDA revenue (c) 186 207 145 JDA expense (c) 60 84 49 Intercompany natural gas purchases (d) 76 78 77 Duke Energy Florida Corporate governance and shared service expenses (a) $ 316 $ 329 $ 298 Indemnification coverages (b) 22 21 23 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 354 $ 374 $ 363 Indemnification coverages (b) 4 5 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 412 $ 405 $ 370 Indemnification coverages (b) 7 7 8 Piedmont Corporate governance and shared service expenses (a) $ 138 $ 170 $ 50 Indemnification coverages (b) 3 2 2 Intercompany natural gas sales (d) 91 93 86 Natural gas storage and transportation costs (e) 23 25 25 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA, which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power pursuant to the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress natural gas-fired generation facilities. Piedmont records the sales in Operating Revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases as a component of Fuel used in electric generation and purchased power on their respective Consolidated Statements of Operations and Comprehensive Income. These intercompany revenues and expenses are eliminated in consolidation. (e) Piedmont has related party transactions as a customer of its equity method investments in Pine Needle, Hardy Storage, and Cardinal natural gas storage and transportation facilities. These expenses are included in Cost of natural gas on Piedmont's Consolidated Statements of Operations and Comprehensive Income. In addition to the amounts presented above, the Subsidiary Registrants have other affiliate transactions, including rental of office space, participation in a money pool arrangement, other operational transactions and their proportionate share of certain charged expenses. See Note 7 for more information regarding money pool. These transactions of the Subsidiary Registrants are incurred in the ordinary course of business and are eliminated in consolidation. As discussed in Note 18 , certain trade receivables have been sold by Duke Energy Ohio and Duke Energy Indiana to CRC, an affiliate formed by a subsidiary of Duke Energy. The proceeds obtained from the sales of receivables are largely cash but do include a subordinated note from CRC for a portion of the purchase price. Intercompany Income Taxes Duke Energy and the Subsidiary Registrants file a consolidated federal income tax return and other state and jurisdictional returns. The Subsidiary Registrants have a tax sharing agreement with Duke Energy for the allocation of consolidated tax liabilities and benefits. Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont December 31, 2019 Intercompany income tax receivable $ — $ 125 $ 28 $ — $ 9 $ 28 $ 13 Intercompany income tax payable 5 — — 2 — — — December 31, 2018 Intercompany income tax receivable $ 52 $ 47 $ 29 $ — $ — $ 8 $ — Intercompany income tax payable — — — 16 3 — 45

Derivatives and Hedging

Derivatives and Hedging	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING The Duke Energy Registrants use commodity and interest rate contracts to manage commodity price risk and interest rate risk. The primary use of commodity derivatives is to hedge the generation portfolio against changes in the prices of electricity and natural gas. Piedmont enters into natural gas supply contracts to provide diversification, reliability and natural gas cost benefits to its customers. Interest rate derivatives are used to manage interest rate risk associated with borrowings. All derivative instruments not identified as NPNS are recorded at fair value as assets or liabilities on the Consolidated Balance Sheets. Cash collateral related to derivative instruments executed under master netting arrangements is offset against the collateralized derivatives on the Consolidated Balance Sheets. The cash impacts of settled derivatives are recorded as operating activities on the Consolidated Statements of Cash Flows. INTEREST RATE RISK The Duke Energy Registrants are exposed to changes in interest rates as a result of their issuance or anticipated issuance of variable-rate and fixed-rate debt and commercial paper. Interest rate risk is managed by limiting variable-rate exposures to a percentage of total debt and by monitoring changes in interest rates. To manage risk associated with changes in interest rates, the Duke Energy Registrants may enter into interest rate swaps, U.S. Treasury lock agreements and other financial contracts. In anticipation of certain fixed-rate debt issuances, a series of forward-starting interest rate swaps or Treasury locks may be executed to lock in components of current market interest rates. These instruments are later terminated prior to or upon the issuance of the corresponding debt. Cash Flow Hedges For a derivative designated as hedging the exposure to variable cash flows of a future transaction, referred to as a cash flow hedge, the effective portion of the derivative's gain or loss is initially reported as a component of other comprehensive income and subsequently reclassified into earnings once the future transaction impacts earnings. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. Gains and losses reclassified out of AOCI for the years ended December 31, 2019 , 2018 and 2017 were not material. Duke Energy's interest rate derivatives designated as hedges include interest rate swaps used to hedge existing debt within the Commercial Renewables business and forward-starting interest rate swaps not accounted for under regulatory accounting. Undesignated Contracts Undesignated contracts primarily include contracts not designated as a hedge because they are accounted for under regulatory accounting or contracts that do not qualify for hedge accounting. Duke Energy’s interest rate swaps for its regulated operations employ regulatory accounting. With regulatory accounting, the mark-to-market gains or losses on the swaps are deferred as regulatory liabilities or regulatory assets, respectively. Regulatory assets and liabilities are amortized consistent with the treatment of the related costs in the ratemaking process. The accrual of interest on the swaps is recorded as Interest Expense on the Duke Energy Registrant's Consolidated Statements of Operations and Comprehensive Income. The following tables show notional amounts of outstanding derivatives related to interest rate risk. December 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 993 $ — $ — $ — $ — $ — Undesignated contracts 1,277 450 800 250 550 27 Total notional amount (a) $ 2,270 $ 450 $ 800 $ 250 $ 550 $ 27 December 31, 2018 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 923 $ — $ — $ — $ — $ — Undesignated contracts 1,721 300 1,200 650 550 27 Total notional amount $ 2,644 $ 300 $ 1,200 $ 650 $ 550 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $693 million in cash flow hedges as of December 31, 2019 , and $422 million in cash flow hedges and $194 million in undesignated contracts as of December 31, 2018 . COMMODITY PRICE RISK The Duke Energy Registrants are exposed to the impact of changes in the prices of electricity purchased and sold in bulk power markets and coal and natural gas purchases, including Piedmont's natural gas supply contracts. Exposure to commodity price risk is influenced by a number of factors including the term of contracts, the liquidity of markets and delivery locations. For the Subsidiary Registrants, bulk power electricity and coal and natural gas purchases flow through fuel adjustment clauses, formula based contracts or other cost sharing mechanisms. Differences between the costs included in rates and the incurred costs, including undesignated derivative contracts, are largely deferred as regulatory assets or regulatory liabilities. Piedmont policies allow for the use of financial instruments to hedge commodity price risks. The strategy and objective of these hedging programs are to use the financial instruments to reduce gas cost volatility for customers. Volumes The tables below include volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. The Duke Energy Registrants have netted contractual amounts where offsetting purchase and sale contracts exist with identical delivery locations and times of delivery. Where all commodity positions are perfectly offset, no quantities are shown. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 15,858 — — — — 1,887 13,971 — Natural gas (millions of Dth) 704 130 160 160 — — 3 411 December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 15,286 — — — — 1,786 13,500 — Natural gas (millions of Dth) 739 121 169 166 3 — 1 448 U.S. EQUITY SECURITIES RISK In May 2019, Duke Energy Florida entered into a Decommissioning Services Agreement for the accelerated decommissioning of Crystal River Unit 3 with ADP CR3, LLC and ADP SF1, LLC. See Note 4 for additional information on the accelerated decommissioning. Duke Energy Florida executed U.S. equity option collars within the NDTF in May 2019 to preserve the U.S. equity portfolio value in the Duke Energy Florida NDTF in the event the accelerated decommissioning is approved. These option collars were executed as a purchase of a put option and the sale of a call option on certain U.S. equity index funds. The put and call options create a collar to guarantee a minimum and maximum investment value for the Duke Energy Florida NDTF U.S. equity portfolio. The put and call options were entered into at zero-cost, with the price to purchase the puts offset entirely by the funds received to sell the calls. As of December 31, 2019 , the aggregate notional amount of both the put and call options was 305,000 units in U.S. equity security index funds. The options are not designated as hedging instruments. Substantially all of Duke Energy Florida’s NDTF qualifies for regulatory accounting. With regulatory accounting, the mark-to-market gains or losses on the options are deferred as regulatory liabilities or regulatory assets, respectively. LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES RECOGNIZED IN THE CONSOLIDATED BALANCE SHEETS The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 17 $ — $ — $ — $ — $ 3 $ 13 $ 1 Noncurrent 1 — — — — 1 — — Total Derivative Assets – Commodity Contracts $ 18 $ — $ — $ — $ — $ 4 $ 13 $ 1 Interest Rate Contracts Not Designated as Hedging Instruments Current 6 — 6 — 6 — — — Total Derivative Assets – Interest Rate Contracts $ 6 $ — $ 6 $ — $ 6 $ — $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 1 — 1 — 1 — — — Total Derivative Assets – Equity Securities Contracts $ 1 $ — $ 1 $ — $ 1 $ — $ — $ — Total Derivative Assets $ 25 $ — $ 7 $ — $ 7 $ 4 $ 13 $ 1 Derivative Liabilities December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 67 $ 33 $ 26 $ 26 $ — $ — $ 1 $ 7 Noncurrent 156 10 37 22 — — — 110 Total Derivative Liabilities – Commodity Contracts $ 223 $ 43 $ 63 $ 48 $ — $ — $ 1 $ 117 Interest Rate Contracts Designated as Hedging Instruments Current $ 19 $ — $ — $ — $ — $ — $ — $ — Noncurrent 21 — — — — — — — Not Designated as Hedging Instruments Current 8 6 1 1 — 1 — — Noncurrent 5 — — — — 5 — — Total Derivative Liabilities – Interest Rate Contracts $ 53 $ 6 $ 1 $ 1 $ — $ 6 $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 24 — 24 — 24 — — — Total Derivative Liabilities – Equity Security Contracts $ 24 $ — $ 24 $ — $ 24 $ — $ — $ — Total Derivative Liabilities $ 300 $ 49 $ 88 $ 49 $ 24 $ 6 $ 1 $ 117 Derivative Assets December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 35 $ 2 $ 2 $ 2 $ — $ 6 $ 23 $ 3 Noncurrent 4 1 2 2 — — — — Total Derivative Assets – Commodity Contracts $ 39 $ 3 $ 4 $ 4 $ — $ 6 $ 23 $ 3 Interest Rate Contracts Designated as Hedging Instruments Current $ 1 $ — $ — $ — $ — $ — $ — $ — Noncurrent 3 — — — — — — — Not Designated as Hedging Instruments Current 2 — — — — — — — Noncurrent 12 — — — — — — — Total Derivative Assets – Interest Rate Contracts $ 18 $ — $ — $ — $ — $ — $ — $ — Total Derivative Assets $ 57 $ 3 $ 4 $ 4 $ — $ 6 $ 23 $ 3 Derivative Liabilities December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 33 $ 14 $ 10 $ 5 $ 6 $ — $ — $ 8 Noncurrent 158 10 15 6 — — — 133 Total Derivative Liabilities – Commodity Contracts $ 191 $ 24 $ 25 $ 11 $ 6 $ — $ — $ 141 Interest Rate Contracts Designated as Hedging Instruments Current $ 12 $ — $ — $ — $ — $ — $ — $ — Noncurrent 6 — — — — — — — Not Designated as Hedging Instruments Current 23 9 13 11 2 1 — — Noncurrent 10 — 6 5 1 4 — — Total Derivative Liabilities – Interest Rate Contracts $ 51 $ 9 $ 19 $ 16 $ 3 $ 5 $ — $ — Total Derivative Liabilities $ 242 $ 33 $ 44 $ 27 $ 9 $ 5 $ — $ 141 OFFSETTING ASSETS AND LIABILITIES The following tables present the line items on the Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The gross amounts offset in the tables below show the effect of these netting arrangements on financial position and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 24 $ — $ 7 $ — $ 7 $ 3 $ 13 $ 1 Gross amounts offset (1 ) — (1 ) — (1 ) — — — Net amounts presented in Current Assets: Other $ 23 $ — $ 6 $ — $ 6 $ 3 $ 13 $ 1 Noncurrent Gross amounts recognized $ 1 $ — $ — $ — $ — $ 1 $ — $ — Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Assets: Other $ 1 $ — $ — $ — $ — $ 1 $ — $ — Derivative Liabilities December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 118 $ 39 $ 51 $ 27 $ 24 $ 1 $ 1 $ 7 Gross amounts offset (24 ) — (24 ) — (24 ) — — — Net amounts presented in Current Liabilities: Other $ 94 $ 39 $ 27 $ 27 $ — $ 1 $ 1 $ 7 Noncurrent Gross amounts recognized $ 182 $ 10 $ 37 $ 22 $ — $ 5 $ — $ 110 Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 182 $ 10 $ 37 $ 22 $ — $ 5 $ — $ 110 Derivative Assets December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 38 $ 2 $ 2 $ 2 $ — $ 6 $ 23 $ 3 Gross amounts offset (3 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Assets: Other $ 35 $ — $ — $ — $ — $ 6 $ 23 $ 3 Noncurrent Gross amounts recognized $ 19 $ 1 $ 2 $ 2 $ — $ — $ — $ — Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 16 $ — $ — $ — $ — $ — $ — $ — Derivative Liabilities December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 68 $ 23 $ 23 $ 16 $ 8 $ 1 $ — $ 8 Gross amounts offset (4 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Liabilities: Other $ 64 $ 21 $ 21 $ 14 $ 8 $ 1 $ — $ 8 Noncurrent Gross amounts recognized $ 174 $ 10 $ 21 $ 11 $ 1 $ 4 $ — $ 133 Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 171 $ 9 $ 19 $ 9 $ 1 $ 4 $ — $ 133 OBJECTIVE CREDIT CONTINGENT FEATURES Certain derivative contracts contain objective credit contingent features. These features include the requirement to post cash collateral or letters of credit if specific events occur, such as a credit rating downgrade below investment grade. The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. December 31, 2019 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 79 $ 35 $ 44 $ 44 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 79 35 44 44 December 31, 2018 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 44 $ 19 $ 25 $ 25 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 44 19 25 25 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative and cash collateral must be executed with the same counterparty under the same master netting arrangement.

Investments in Debt and Equity

Investments in Debt and Equity Securities	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES Duke Energy's investments in debt and equity securities are primarily comprised of investments held in (i) the NDTF at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) the grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to OPEB plans and (iii) Bison. The Duke Energy Registrants classify investments in debt securities as AFS and investments in equity securities as FV-NI. For investments in debt securities classified as AFS, the unrealized gains and losses are included in other comprehensive income until realized, at which time, they are reported though net income. For investments in equity securities classified as FV-NI, both realized and unrealized gains and losses are reported through net income. Substantially all of Duke Energy's investments in debt and equity securities qualify for regulatory accounting, and accordingly, all associated realized and unrealized gains and losses on these investments are deferred as a regulatory asset or liability. Duke Energy classifies the majority of investments in debt and equity securities as long term, unless otherwise noted. Investment Trusts The investments within the Investment Trusts are managed by independent investment managers with discretion to buy, sell and invest pursuant to the objectives set forth by the trust agreements. The Duke Energy Registrants have limited oversight of the day-to-day management of these investments. As a result, the ability to hold investments in unrealized loss positions is outside the control of the Duke Energy Registrants. Accordingly, all unrealized losses associated with debt securities within the Investment Trusts are considered OTTIs and are recognized immediately and deferred to regulatory accounts where appropriate. Other AFS Securities Unrealized gains and losses on all other AFS securities are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired. The Duke Energy Registrants analyze all investment holdings each reporting period to determine whether a decline in fair value should be considered other-than-temporary. If an OTTI exists, the unrealized credit loss is included in earnings. There were no material credit losses as of December 31, 2019 , and 2018 . Other Investments amounts are recorded in Other within Other Noncurrent Assets on the Consolidated Balance Sheets. DUKE ENERGY The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 101 $ — $ — $ 88 Equity securities 3,523 55 5,661 2,402 95 4,475 Corporate debt securities 37 1 603 4 13 566 Municipal bonds 13 — 368 1 4 353 U.S. government bonds 33 1 1,256 14 12 1,076 Other debt securities 3 — 141 — 2 148 Total NDTF Investments $ 3,609 $ 57 $ 8,130 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 22 Equity securities 57 — 122 36 1 99 Corporate debt securities 3 — 67 — 2 60 Municipal bonds 4 — 94 — 1 85 U.S. government bonds 2 — 41 1 — 45 Other debt securities — — 56 — 1 58 Total Other Investments $ 66 $ — $ 432 $ 37 $ 5 $ 369 Total Investments $ 3,675 $ 57 $ 8,562 $ 2,458 $ 131 $ 7,075 The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 372 Due after one through five years 550 Due after five through 10 years 452 Due after 10 years 1,252 Total $ 2,626 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 172 $ 168 Realized losses 151 126 AFS: Realized gains 94 22 Realized losses 67 51 Year Ended December 31, (in millions) 2017 Realized gains $ 202 Realized losses 160 DUKE ENERGY CAROLINAS The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 21 $ — $ — $ 29 Equity securities 1,914 8 3,154 1,309 54 2,484 Corporate debt securities 21 1 361 2 9 341 Municipal bonds 3 — 96 — 1 81 U.S. government bonds 16 1 578 5 8 475 Other debt securities 3 — 137 — 2 143 Total NDTF Investments $ 1,957 $ 10 $ 4,347 $ 1,316 $ 74 $ 3,553 The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 51 Due after one through five years 253 Due after five through 10 years 181 Due after 10 years 687 Total $ 1,172 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 113 $ 89 Realized losses 107 73 AFS: Realized gains 55 19 Realized losses 38 35 Year Ended December 31, (in millions) 2017 Realized gains $ 135 Realized losses 103 PROGRESS ENERGY The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 80 $ — $ — $ 59 Equity securities 1,609 47 2,507 1,093 41 1,991 Corporate debt securities 16 — 242 2 4 225 Municipal bonds 10 — 272 1 3 272 U.S. government bonds 17 — 678 9 4 601 Other debt securities — — 4 — — 5 Total NDTF Investments $ 1,652 $ 47 $ 3,783 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 49 $ — $ — $ 17 Municipal bonds 3 — 51 — — 47 Total Other Investments $ 3 $ — $ 100 $ — $ — $ 64 Total Investments $ 1,655 $ 47 $ 3,883 $ 1,105 $ 52 $ 3,217 The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 311 Due after one through five years 256 Due after five through 10 years 211 Due after 10 years 469 Total $ 1,247 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 59 $ 79 Realized losses 44 53 AFS: Realized gains 36 3 Realized losses 29 15 Year Ended December 31, (in millions) 2017 Realized gains $ 65 Realized losses 56 DUKE ENERGY PROGRESS The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 53 $ — $ — $ 46 Equity securities 1,258 21 2,077 833 30 1,588 Corporate debt securities 16 — 242 2 3 171 Municipal bonds 10 — 272 1 3 271 U.S. government bonds 16 — 403 6 3 415 Other debt securities — — 4 — — 3 Total NDTF Investments $ 1,300 $ 21 $ 3,051 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Total Other Investments $ — $ — $ 2 $ — $ — $ 6 Total Investments $ 1,300 $ 21 $ 3,053 $ 842 $ 39 $ 2,500 The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 34 Due after one through five years 247 Due after five through 10 years 204 Due after 10 years 436 Total $ 921 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 38 $ 68 Realized losses 33 48 AFS: Realized gains 7 2 Realized losses 5 10 Year Ended December 31, (in millions) 2017 Realized gains $ 54 Realized losses 48 DUKE ENERGY FLORIDA The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 27 $ — $ — $ 13 Equity securities 351 26 430 260 11 403 Corporate debt securities — — — — 1 54 Municipal bonds — — — — — 1 U.S. government bonds 1 — 275 3 1 186 Other debt securities — — — — — 2 Total NDTF Investments (a) $ 352 $ 26 $ 732 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 1 Municipal bonds 3 — 51 — — 47 Total Other Investments $ 3 $ — $ 55 $ — $ — $ 48 Total Investments $ 355 $ 26 $ 787 $ 263 $ 13 $ 707 (a) During the year ended December 31, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 277 Due after one through five years 9 Due after five through 10 years 7 Due after 10 years 33 Total $ 326 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 21 $ 11 Realized losses 11 5 AFS: Realized gains 29 1 Realized losses 24 5 Year Ended December 31, (in millions) 2017 Realized gains $ 11 Realized losses 8 DUKE ENERGY INDIANA The following table presents the estimated fair value of investments in debt and equity securities; equity investments are measured at FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value Investments Equity securities $ 43 $ — $ 81 $ 29 $ — $ 67 Corporate debt securities — — 6 — — 8 Municipal bonds 1 — 36 — 1 33 U.S. government bonds — — 2 — — — Total Investments $ 44 $ — $ 125 $ 29 $ 1 $ 108 The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 4 Due after one through five years 16 Due after five through 10 years 7 Due after 10 years 17 Total $ 44 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the year ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were insignificant.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is the exchange price to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. The fair value definition focuses on an exit price versus the acquisition cost. Fair value measurements use market data or assumptions market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs may be readily observable, corroborated by market data, or generally unobservable. Valuation techniques maximize the use of observable inputs and minimize use of unobservable inputs. A midmarket pricing convention (the midpoint price between bid and ask prices) is permitted for use as a practical expedient. Fair value measurements are classified in three levels based on the fair value hierarchy as defined by GAAP. Certain investments are not categorized within the fair value hierarchy. These investments are measured at fair value using the NAV per share practical expedient. The net asset value is derived based on the investment cost, less any impairment, plus or minus changes resulting from observable price changes for an identical or similar investment of the same issuer. Fair value accounting guidance permits entities to elect to measure certain financial instruments that are not required to be accounted for at fair value, such as equity method investments or the company’s own debt, at fair value. The Duke Energy Registrants have not elected to record any of these items at fair value. Valuation methods of the primary fair value measurements disclosed below are as follows. Investments in equity securities The majority of investments in equity securities are valued using Level 1 measurements. Investments in equity securities are typically valued at the closing price in the principal active market as of the last business day of the quarter. Principal active markets for equity prices include published exchanges such as the NYSE and Nasdaq Stock Market. Foreign equity prices are translated from their trading currency using the currency exchange rate in effect at the close of the principal active market. There was no after-hours market activity that was required to be reflected in the reported fair value measurements. Investments in debt securities Most investments in debt securities are valued using Level 2 measurements because the valuations use interest rate curves and credit spreads applied to the terms of the debt instrument (maturity and coupon interest rate) and consider the counterparty credit rating. If the market for a particular fixed-income security is relatively inactive or illiquid, the measurement is Level 3. Commodity derivatives Commodity derivatives with clearinghouses are classified as Level 1. If forward price curves are not observable for the full term of the contract and the unobservable period had more than an insignificant impact on the valuation, the commodity derivative is classified as Level 3. In isolation, increases (decreases) in natural gas forward prices result in favorable (unfavorable) fair value adjustments for natural gas purchase contracts; and increases (decreases) in electricity forward prices result in unfavorable (favorable) fair value adjustments for electricity sales contracts. Duke Energy regularly evaluates and validates pricing inputs used to estimate the fair value of natural gas commodity contracts by a market participant price verification procedure. This procedure provides a comparison of internal forward commodity curves to market participant generated curves. Interest rate derivatives Most over-the-counter interest rate contract derivatives are valued using financial models that utilize observable inputs for similar instruments and are classified as Level 2. Inputs include forward interest rate curves, notional amounts, interest rates and credit quality of the counterparties. Other fair value considerations See Note 12 for a discussion of the valuation of goodwill and intangible assets. DUKE ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 15 . See Note 16 for additional information related to investments by major security type for the Duke Energy Registrants. December 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 5,684 $ 5,633 $ — $ — $ 51 NDTF debt securities 2,469 826 1,643 — — Other equity securities 122 122 — — — Other debt securities 310 91 219 — — Derivative assets 25 3 7 15 — Total assets 8,610 6,675 1,869 15 51 NDTF equity security contracts (23 ) — (23 ) — — Derivative liabilities (277 ) (15 ) (145 ) (117 ) — Net assets (liabilities) $ 8,310 $ 6,660 $ 1,701 $ (102 ) $ 51 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 4,475 $ 4,410 $ — $ — $ 65 NDTF debt securities 2,231 576 1,655 — — Other equity securities 99 99 — — — Other debt securities 270 67 203 — — Derivative assets 57 4 25 28 — Total assets 7,132 5,156 1,883 28 65 Derivative liabilities (242 ) (11 ) (90 ) (141 ) — Net assets (liabilities) $ 6,890 $ 5,145 $ 1,793 $ (113 ) $ 65 The following table provides reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. December 31, 2019 December 31, 2018 (in millions) Derivatives (net) Derivatives (net) Balance at beginning of period $ (113 ) $ (114 ) Purchases, sales, issuances and settlements: Purchases 37 57 Settlements (44 ) (57 ) Total gains included on the Consolidated Balance Sheet 18 1 Balance at end of period $ (102 ) $ (113 ) DUKE ENERGY CAROLINAS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 3,154 $ 3,103 $ — $ 51 NDTF debt securities 1,193 227 966 — Total assets 4,347 3,330 966 51 Derivative liabilities (49 ) — (49 ) — Net assets $ 4,298 $ 3,330 $ 917 $ 51 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 2,484 $ 2,419 $ — $ 65 NDTF debt securities 1,069 149 920 — Derivative assets 3 — 3 — Total assets 3,556 2,568 923 65 Derivative liabilities (33 ) — (33 ) — Net assets $ 3,523 $ 2,568 $ 890 $ 65 PROGRESS ENERGY The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,530 $ 2,530 $ — $ 1,991 $ 1,991 $ — NDTF debt securities 1,276 599 677 1,162 427 735 Other debt securities 100 49 51 64 17 47 Derivative assets 7 — 7 4 — 4 Total assets 3,913 3,178 735 3,221 2,435 786 NDTF equity security contracts (23 ) — (23 ) — — — Derivative liabilities (65 ) — (65 ) (44 ) — (44 ) Net assets $ 3,825 $ 3,178 $ 647 $ 3,177 $ 2,435 $ 742 DUKE ENERGY PROGRESS The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,077 $ 2,077 $ — $ 1,588 $ 1,588 $ — NDTF debt securities 974 297 677 906 294 612 Other debt securities 2 2 — 6 6 — Derivative assets — — — 4 — 4 Total assets 3,053 2,376 677 2,504 1,888 616 Derivative liabilities (49 ) — (49 ) (27 ) — (27 ) Net assets $ 3,004 $ 2,376 $ 628 $ 2,477 $ 1,888 $ 589 DUKE ENERGY FLORIDA The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 453 $ 453 $ — $ 403 $ 403 $ — NDTF debt securities 302 302 — 256 133 123 Other debt securities 55 4 51 48 1 47 Derivative assets 7 — 7 — — — Total assets 817 759 58 707 537 170 NDTF equity security contracts (23 ) — (23 ) — — — Derivative liabilities (1 ) — (1 ) (9 ) — (9 ) Net assets $ 793 $ 759 $ 34 $ 698 $ 537 $ 161 DUKE ENERGY OHIO The recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets were not material at December 31, 2019 , and 2018 . DUKE ENERGY INDIANA The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Other equity securities $ 81 $ 81 $ — $ — $ 67 $ 67 $ — $ — Other debt securities 44 — 44 — 41 — 41 — Derivative assets 13 2 — 11 23 1 — 22 Total assets 138 83 44 11 131 68 41 22 Derivative liabilities (1 ) (1 ) — — — — — — Total assets $ 137 $ 82 $ 44 $ 11 $ 131 $ 68 $ 41 $ 22 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2019 2018 Balance at beginning of period $ 22 $ 27 Purchases, sales, issuances and settlements: Purchases 28 50 Settlements (36 ) (53 ) Total losses included on the Consolidated Balance Sheet (3 ) (2 ) Balance at end of period $ 11 $ 22 PIEDMONT The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 3 Total Fair Value Level 1 Level 3 Derivative assets $ 1 $ 1 $ — $ 3 $ 3 $ — Derivative liabilities (117 ) — (117 ) (141 ) — (141 ) Net (liabilities) assets $ (116 ) $ 1 $ (117 ) $ (138 ) $ 3 $ (141 ) The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2019 2018 Balance at beginning of period $ (141 ) $ (142 ) Total gains and settlements 24 1 Balance at end of period $ (117 ) $ (141 ) QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. December 31, 2019 Weighted Fair Value Average Investment Type (in millions) Valuation Technique Unobservable Input Range Range Duke Energy Ohio FTRs $ 4 RTO auction pricing FTR price – per MWh $ 0.59 – $ 3.47 $ 2.07 Duke Energy Indiana FTRs 11 RTO auction pricing FTR price – per MWh (0.66 ) – 9.24 1.15 Piedmont Natural gas contracts (117 ) Discounted cash flow Forward natural gas curves – price per MMBtu 1.59 – 2.46 1.91 Duke Energy Total Level 3 derivatives $ (102 ) December 31, 2018 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 6 RTO auction pricing FTR price – per MWh $ 1.19 – $ 4.59 Duke Energy Indiana FTRs 22 RTO auction pricing FTR price – per MWh (2.07 ) – 8.27 Piedmont Natural gas contracts (141 ) Discounted cash flow Forward natural gas curves – price per MMBtu 1.87 – 2.95 Duke Energy Total Level 3 derivatives $ (113 ) OTHER FAIR VALUE DISCLOSURES The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. December 31, 2019 December 31, 2018 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy (a) $ 58,126 $ 63,062 $ 54,529 $ 54,534 Duke Energy Carolinas 11,900 13,516 10,939 11,471 Progress Energy 19,634 22,291 18,911 19,885 Duke Energy Progress 9,058 9,934 8,204 8,300 Duke Energy Florida 7,987 9,131 7,321 7,742 Duke Energy Ohio 2,619 2,964 2,165 2,239 Duke Energy Indiana 4,057 4,800 3,782 4,158 Piedmont 2,384 2,642 2,138 2,180 (a) Book value of long-term debt includes $1.5 billion as of December 31, 2019 , and $1.6 billion as of December 31, 2018 , of unamortized debt discount and premium, net in purchase accounting adjustments related to the mergers with Progress Energy and Piedmont that are excluded from fair value of long-term debt. At both December 31, 2019 , and December 31, 2018 , fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and nonrecourse notes payable of VIEs are not materially different from their carrying amounts because of the short-term nature of these instruments and/or because the stated rates approximate market rates.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2019
Variable Interest Entities [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES A VIE is an entity that is evaluated for consolidation using more than a simple analysis of voting control. The analysis to determine whether an entity is a VIE considers contracts with an entity, credit support for an entity, the adequacy of the equity investment of an entity and the relationship of voting power to the amount of equity invested in an entity. This analysis is performed either upon the creation of a legal entity or upon the occurrence of an event requiring reevaluation, such as a significant change in an entity’s assets or activities. A qualitative analysis of control determines the party that consolidates a VIE. This assessment is based on (i) what party has the power to direct the activities of the VIE that most significantly impact its economic performance and (ii) what party has rights to receive benefits or is obligated to absorb losses that could potentially be significant to the VIE. The analysis of the party that consolidates a VIE is a continual reassessment. CONSOLIDATED VIEs The obligations of the consolidated VIEs discussed in the following paragraphs are nonrecourse to the Duke Energy Registrants. The registrants have no requirement to provide liquidity to, purchase assets of or guarantee performance of these VIEs unless noted in the following paragraphs. No financial support was provided to any of the consolidated VIEs during the years ended December 31, 2019 , 2018 , and 2017 , or is expected to be provided in the future, that was not previously contractually required. Receivables Financing – DERF/DEPR/DEFR DERF, DEPR and DEFR are bankruptcy remote, special purpose subsidiaries of Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, respectively. DERF, DEPR and DEFR are wholly owned LLCs with separate legal existence from their parent companies, and their assets are not generally available to creditors of their parent companies. On a revolving basis, DERF, DEPR and DEFR buy certain accounts receivable arising from the sale of electricity and related services from their parent companies. DERF, DEPR and DEFR borrow amounts under credit facilities to buy these receivables. Borrowing availability from the credit facilities is limited to the amount of qualified receivables purchased. The sole source of funds to satisfy the related debt obligations is cash collections from the receivables. Amounts borrowed under the credit facilities are reflected on the Consolidated Balance Sheets as Long-Term Debt. The most significant activity that impacts the economic performance of DERF, DEPR and DEFR are the decisions made to manage delinquent receivables. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida are considered the primary beneficiaries and consolidate DERF, DEPR and DEFR, respectively, as they make those decisions. Receivables Financing – CRC CRC is a bankruptcy remote, special purpose entity indirectly owned by Duke Energy. On a revolving basis, CRC buys certain accounts receivable arising from the sale of electricity, natural gas and related services from Duke Energy Ohio and Duke Energy Indiana. CRC borrows amounts under a credit facility to buy the receivables from Duke Energy Ohio and Duke Energy Indiana. Borrowing availability from the credit facility is limited to the amount of qualified receivables sold to CRC. The sole source of funds to satisfy the related debt obligation is cash collections from the receivables. Amounts borrowed under the credit facility are reflected on Duke Energy's Consolidated Balance Sheets as Long-Term Debt. The proceeds Duke Energy Ohio and Duke Energy Indiana receive from the sale of receivables to CRC are approximately 75% cash and 25% in the form of a subordinated note from CRC. The subordinated note is a retained interest in the receivables sold. Depending on collection experience, additional equity infusions to CRC may be required by Duke Energy to maintain a minimum equity balance of $3 million . CRC is considered a VIE because (i) equity capitalization is insufficient to support its operations, (ii) power to direct the activities that most significantly impact the economic performance of the entity is not held by the equity holder and (iii) deficiencies in net worth of CRC are funded by Duke Energy. The most significant activities that impact the economic performance of CRC are decisions made to manage delinquent receivables. Duke Energy is considered the primary beneficiary and consolidates CRC as it makes these decisions. Neither Duke Energy Ohio nor Duke Energy Indiana consolidate CRC. Receivables Financing – Credit Facilities The following table summarizes the amounts and expiration dates of the credit facilities and associated restricted receivables described above. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida (in millions) CRC DERF DEPR DEFR Expiration date February 2023 December 2022 February 2021 April 2021 Credit facility amount $ 350 $ 475 $ 325 $ 250 Amounts borrowed at December 31, 2019 350 474 325 250 Amounts borrowed at December 31, 2018 325 450 300 225 Restricted Receivables at December 31, 2019 522 642 489 336 Restricted Receivables at December 31, 2018 564 699 547 357 Nuclear Asset-Recovery Bonds – Duke Energy Florida Project Finance, LLC (DEFPF) DEFPF is a bankruptcy remote, wholly owned special purpose subsidiary of Duke Energy Florida. DEFPF was formed in 2016 for the sole purpose of issuing nuclear asset-recovery bonds to finance Duke Energy Florida's unrecovered regulatory asset related to Crystal River Unit 3. In 2016, DEFPF issued senior secured bonds and used the proceeds to acquire nuclear asset-recovery property from Duke Energy Florida. The nuclear asset-recovery property acquired includes the right to impose, bill, collect and adjust a non-bypassable nuclear asset-recovery charge from all Duke Energy Florida retail customers until the bonds are paid in full and all financing costs have been recovered. The nuclear asset-recovery bonds are secured by the nuclear asset-recovery property and cash collections from the nuclear asset-recovery charges are the sole source of funds to satisfy the debt obligation. The bondholders have no recourse to Duke Energy Florida. DEFPF is considered a VIE primarily because the equity capitalization is insufficient to support its operations. Duke Energy Florida has the power to direct the significant activities of the VIE as described above and therefore Duke Energy Florida is considered the primary beneficiary and consolidates DEFPF. The following table summarizes the impact of DEFPF on Duke Energy Florida's Consolidated Balance Sheets. December 31, (in millions) 2019 2018 Receivables of VIEs $ 5 $ 5 Regulatory Assets: Current 52 52 Current Assets: Other 39 39 Other Noncurrent Assets: Regulatory assets 989 1,041 Current Liabilities: Other 10 10 Current maturities of long-term debt 54 53 Long-Term Debt 1,057 1,111 Commercial Renewables Certain of Duke Energy’s renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. Assets are restricted and cannot be pledged as collateral or sold to third parties without prior approval of debt holders. Additionally, Duke Energy has VIEs associated with tax equity arrangements entered into with third-party investors in order to finance the cost of renewable assets eligible for tax credits. The activities that most significantly impacted the economic performance of these renewable energy facilities were decisions associated with siting, negotiating PPAs and EPC agreements, and decisions associated with ongoing operations and maintenance-related activities. Duke Energy is considered the primary beneficiary and consolidates the entities as it is responsible for all of these decisions. The table below presents material balances reported on Duke Energy's Consolidated Balance Sheets related to Commercial Renewables VIEs. December 31, (in millions) 2019 2018 Current Assets: Other $ 203 $ 123 Property, Plant and Equipment: Cost 5,747 4,007 Accumulated depreciation and amortization (1,041 ) (698 ) Other Noncurrent Assets: Other 106 261 Current maturities of long-term debt 162 174 Long-Term Debt 1,541 1,587 Other Noncurrent Liabilities: AROs 127 106 Other Noncurrent Liabilities: Other 228 212 NON-CONSOLIDATED VIEs The following tables summarize the impact of non-consolidated VIEs on the Consolidated Balance Sheets. December 31, 2019 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs (a) Total Ohio Indiana Receivables from affiliated companies $ — $ (1 ) $ — $ (1 ) $ 64 $ 77 Investments in equity method unconsolidated affiliates 1,179 300 — 1,479 — — Total assets $ 1,179 $ 299 $ — $ 1,478 $ 64 $ 77 Taxes accrued (1 ) — — (1 ) — — Other current liabilities — — 4 4 — — Deferred income taxes 59 — — 59 — — Other noncurrent liabilities — — 11 11 — — Total liabilities $ 58 $ — $ 15 $ 73 $ — $ — Net assets (liabilities) $ 1,121 $ 299 $ (15 ) $ 1,405 $ 64 $ 77 (a) Duke Energy holds a 50% equity interest in Pioneer. As of December 31, 2018, Pioneer was considered a VIE due to having insufficient equity to finance its own activities without subordinated financial support. In October 2019, Pioneer closed on a private placement debt offering that gave Pioneer sufficient equity to finance its own activities and, therefore, is no longer considered a VIE. Duke Energy's investment in Pioneer was $57 million at December 31, 2019. December 31, 2018 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 93 $ 118 Investments in equity method unconsolidated affiliates 822 190 48 1,060 — — Total assets $ 822 $ 190 $ 48 $ 1,060 $ 93 $ 118 Taxes accrued (1 ) — — (1 ) — — Other current liabilities — — 4 4 — — Deferred income taxes 21 — — 21 — — Other noncurrent liabilities — — 12 12 — — Total liabilities $ 20 $ — $ 16 $ 36 $ — $ — Net assets $ 802 $ 190 $ 32 $ 1,024 $ 93 $ 118 The Duke Energy Registrants are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying values shown above except for the PPA with OVEC, which is discussed below, and various guarantees, including Duke Energy's guarantee agreement to support its share of the ACP revolving credit facility. Duke Energy's maximum exposure to loss under the terms of the guarantee is $827 million , which represents 47% of the outstanding borrowings under the credit facility as of December 31, 2019 . For more information on various guarantees, refer to Note 8 . Pipeline Investments Duke Energy has investments in various joint ventures with pipeline projects currently under construction. These entities are considered VIEs due to having insufficient equity to finance their own activities without subordinated financial support. Duke Energy does not have the power to direct the activities that most significantly impact the economic performance, the obligation to absorb losses or the right to receive benefits of these VIEs and therefore does not consolidate these entities. The table below presents Duke Energy's ownership interest and investment balances in these joint ventures. VIE Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest 2019 2018 ACP (a) 47 % $ 1,179 $ 797 Constitution (b) 24 % — 25 Total $ 1,179 $ 822 (a) Duke Energy evaluated this investment for impairment as of December 31, 2019, and 2018, and determined that fair value approximated carrying value and therefore no impairment was necessary. (b) During the years ended December 31, 2019, and 2018, Duke Energy recorded an OTTI of $25 million and $55 million , respectively, related to Constitution within Equity in earnings of unconsolidated affiliates on Duke Energy's Consolidated Statements of Income. The current year charge resulted in the full write-down of Duke Energy's investment in Constitution. See Notes 4 and 13 for additional information. Commercial Renewables Duke Energy has investments in various renewable energy project entities. Some of these entities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. Duke Energy does not consolidate these VIEs because power to direct and control key activities is shared jointly by Duke Energy and other owners. In 2019, Duke Energy acquired a majority ownership in a portfolio of distributed fuel cell projects from Bloom Energy Corporation. Duke Energy is not the primary beneficiary of the assets within the portfolio and does not consolidate the assets in the portfolio. OVEC Duke Energy Ohio’s 9% ownership interest in OVEC is considered a non-consolidated VIE due to OVEC having insufficient equity to finance its activities without subordinated financial support. The activities that most significantly impact OVEC's economic performance include fuel strategy and supply activities and decisions associated with ongoing operations and maintenance-related activities. Duke Energy Ohio does not have the unilateral power to direct these activities, and therefore, does not consolidate OVEC. As a counterparty to an Inter-Company Power Agreement (ICPA), Duke Energy Ohio has a contractual arrangement to receive entitlements to capacity and energy from OVEC’s power plants through June 2040 commensurate with its power participation ratio, which is equivalent to Duke Energy Ohio's ownership interest. Costs, including fuel, operating expenses, fixed costs, debt amortization and interest expense, are allocated to counterparties to the ICPA based on their power participation ratio. The value of the ICPA is subject to variability due to fluctuation in power prices and changes in OVEC's cost of business. On March 31, 2018, FES, a subsidiary of FirstEnergy Corp. and an ICPA counterparty with a power participation ratio of 4.85% , filed for Chapter 11 bankruptcy, which could increase costs allocated to the counterparties. On July 31, 2018, the bankruptcy court rejected the FES ICPA, which means OVEC is an unsecured creditor in the FES bankruptcy proceeding. Duke Energy Ohio cannot predict the impact of the bankruptcy filing on its OVEC interests. In addition, certain proposed environmental rulemaking could result in future increased OVEC cost allocations. See Note 4 for additional information. CRC See discussion under Consolidated VIEs for additional information related to CRC. Amounts included in Receivables from affiliated companies in the above table for Duke Energy Ohio and Duke Energy Indiana reflect their retained interest in receivables sold to CRC. These subordinated notes held by Duke Energy Ohio and Duke Energy Indiana are stated at fair value. Carrying values of retained interests are determined by allocating carrying value of the receivables between assets sold and interests retained based on relative fair value. The allocated bases of the subordinated notes are not materially different than their face value because (i) the receivables generally turnover in less than two months, (ii) credit losses are reasonably predictable due to the broad customer base and lack of significant concentration and (iii) the equity in CRC is subordinate to all retained interests and thus would absorb losses first. The hypothetical effect on fair value of the retained interests assuming both a 10% and a 20% unfavorable variation in credit losses or discount rates is not material due to the short turnover of receivables and historically low credit loss history. Interest accrues to Duke Energy Ohio and Duke Energy Indiana on the retained interests using the acceptable yield method. This method generally approximates the stated rate on the notes since the allocated basis and the face value are nearly equivalent. An impairment charge is recorded against the carrying value of both retained interests and purchased beneficial interest whenever it is determined that an OTTI has occurred. Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2019 2018 2019 2018 Anticipated credit loss ratio 0.6 % 0.5 % 0.3 % 0.3 % Discount rate 3.3 % 3.0 % 3.3 % 3.0 % Receivable turnover rate 13.4 % 13.5 % 11.5 % 11.0 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana December 31, December 31, (in millions) 2019 2018 2019 2018 Receivables sold $ 253 $ 269 $ 307 $ 336 Less: Retained interests 64 93 77 118 Net receivables sold $ 189 $ 176 $ 230 $ 218 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Years Ended December 31, Years Ended December 31, (in millions) 2019 2018 2017 2019 2018 2017 Sales Receivables sold $ 1,979 $ 1,987 $ 1,879 $ 2,837 $ 2,842 $ 2,711 Loss recognized on sale 14 13 10 17 16 12 Cash flows Cash proceeds from receivables sold 1,993 1,967 1,865 2,860 2,815 2,694 Collection fees received 1 1 1 1 1 1 Return received on retained interests 6 6 3 9 9 7 Cash flows from sales of receivables are reflected within Cash Flows From Operating Activities on Duke Energy Ohio’s and Duke Energy Indiana’s Consolidated Statements of Cash Flows. Collection fees received in connection with servicing transferred accounts receivable are included in Operation, maintenance and other on Duke Energy Ohio’s and Duke Energy Indiana’s Consolidated Statements of Operations and Comprehensive Income. The loss recognized on sales of receivables is calculated monthly by multiplying receivables sold during the month by the required discount. The required discount is derived monthly utilizing a three-year weighted average formula that considers charge-off history, late charge history and turnover history on the sold receivables, as well as a component for the time value of money. The discount rate, or component for the time value of money, is the prior month-end LIBOR plus a fixed rate of 1.00% .

Revenue

Revenue	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE Duke Energy recognizes revenue consistent with amounts billed under tariff offerings or at contractually agreed upon rates based on actual physical delivery of electric or natural gas service, including estimated volumes delivered when billings have not yet occurred. As such, the majority of Duke Energy’s revenues have fixed pricing based on the contractual terms of the published tariffs, with variability in expected cash flows attributable to the customer’s volumetric demand and ultimate quantities of energy or natural gas supplied and used during the billing period. The stand-alone selling price of related sales are designed to support recovery of prudently incurred costs and an appropriate return on invested assets and are primarily governed by published tariff rates or contractual agreements approved by relevant regulatory bodies. As described in Note 1 , certain excise taxes and franchise fees levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis as part of revenues. Duke Energy elects to account for all other taxes net of revenues. Performance obligations are satisfied over time as energy or natural gas is delivered and consumed with billings generally occurring monthly and related payments due within 30 days, depending on regulatory requirements. In no event does the timing between payment and delivery of the goods and services exceed one year. Using this output method for revenue recognition provides a faithful depiction of the transfer of electric and natural gas service as customers obtain control of the commodity and benefit from its use at delivery. Additionally, Duke Energy has an enforceable right to consideration for energy or natural gas delivered at any discrete point in time and will recognize revenue at an amount that reflects the consideration to which Duke Energy is entitled for the energy or natural gas delivered. As described above, the majority of Duke Energy’s tariff revenues are at-will and, as such, related contracts with customers have an expected duration of one year or less and will not have future performance obligations for disclosure. Additionally, other long-term revenue streams, including wholesale contracts, generally provide services that are part of a single performance obligation, the delivery of electricity or natural gas. As such, other than material fixed consideration under long-term contracts, related disclosures for future performance obligations are also not applicable. Duke Energy earns substantially all of its revenues through its reportable segments, Electric Utilities and Infrastructure, Gas Utilities and Infrastructure and Commercial Renewables. Electric Utilities and Infrastructure Electric Utilities and Infrastructure earns the majority of its revenues through retail and wholesale electric service through the generation, transmission, distribution and sale of electricity. Duke Energy generally provides retail and wholesale electric service customers with their full electric load requirements or with supplemental load requirements when the customer has other sources of electricity. Retail electric service is generally marketed throughout Duke Energy's electric service territory through standard service offers. The standard service offers are through tariffs determined by regulators in Duke Energy's regulated service territory. Each tariff, which is assigned to customers based on customer class, has multiple components such as an energy charge, a demand charge, a basic facilities charge and applicable riders. Duke Energy considers each of these components to be aggregated into a single performance obligation for providing electric service, or in the case of distribution only customers in Duke Energy Ohio, for delivering electricity. Electricity is considered a single performance obligation satisfied over time consistent with the series guidance and is provided and consumed over the billing period, generally one month. Retail electric service is typically provided to at-will customers who can cancel service at any time, without a substantive penalty. Additionally, Duke Energy adheres to applicable regulatory requirements in each jurisdiction to ensure the collectability of amounts billed and appropriate mitigating procedures are followed when necessary. As such, revenue from contracts with customers for such contracts is equivalent to the electricity supplied and billed in that period (including unbilled estimates). Wholesale electric service is generally provided under long-term contracts using cost-based pricing. FERC regulates costs that may be recovered from customers and the amount of return companies are permitted to earn. Wholesale contracts include both energy and demand charges. For full requirements contracts, Duke Energy considers both charges as a single performance obligation for providing integrated electric service. For contracts where energy and demand charges are considered separate performance obligations, energy and demand are each a distinct performance obligation under the series guidance and are satisfied as energy is delivered and stand-ready service is provided on a monthly basis. This service represents consumption over the billing period and revenue is recognized consistent with billings and unbilled estimates, which generally occur monthly. Contractual amounts owed are typically trued up annually based upon incurred costs in accordance with FERC published filings and the specific customer’s actual peak demand. Estimates of variable consideration related to potential additional billings or refunds owed are updated quarterly. The majority of wholesale revenues are full requirements contracts where the customers purchase the substantial majority of their energy needs and do not have a fixed quantity of contractually required energy or capacity. As such, related forecasted revenues are considered optional purchases. Supplemental requirements contracts that include contracted blocks of energy and capacity at contractually fixed prices have the following estimated remaining performance obligations: Remaining Performance Obligations (in millions) 2020 2021 2022 2023 2024 Thereafter Total Progress Energy $ 121 $ 92 $ 87 $ 44 $ 45 $ 58 $ 447 Duke Energy Progress 8 8 8 8 8 — 40 Duke Energy Florida 113 84 79 36 37 58 407 Duke Energy Indiana 10 5 — — — — 15 Revenues for block sales are recognized monthly as energy is delivered and stand-ready service is provided, consistent with invoiced amounts and unbilled estimates. Gas Utilities and Infrastructure Gas Utilities and Infrastructure earns its revenue through retail and wholesale natural gas service through the transportation, distribution and sale of natural gas. Duke Energy generally provides retail and wholesale natural gas service customers with all natural gas load requirements. Additionally, while natural gas can be stored, substantially all natural gas provided by Duke Energy is consumed by customers simultaneously with receipt of delivery. Retail natural gas service is marketed throughout Duke Energy's natural gas service territory using published tariff rates. The tariff rates are established by regulators in Duke Energy's service territories. Each tariff, which is assigned to customers based on customer class, have multiple components, such as a commodity charge, demand charge, customer or monthly charge and transportation costs. Duke Energy considers each of these components to be aggregated into a single performance obligation for providing natural gas service. For contracts where Duke Energy provides all of the customer’s natural gas needs, the delivery of natural gas is considered a single performance obligation satisfied over time, and revenue is recognized monthly based on billings and unbilled estimates as service is provided and the commodity is consumed over the billing period. Additionally, natural gas service is typically at-will and customers can cancel service at any time, without a substantive penalty. Duke Energy also adheres to applicable regulatory requirements to ensure the collectability of amounts billed and receivable and appropriate mitigating procedures are followed when necessary. Certain long-term individually negotiated contracts exist to provide natural gas service. These contracts are regulated and approved by state commissions. The negotiated contracts have multiple components, including a natural gas and a demand charge, similar to retail natural gas contracts. Duke Energy considers each of these components to be a single performance obligation for providing natural gas service. This service represents consumption over the billing period, generally one month. Fixed capacity payments under long-term contracts for the Gas Utilities and Infrastructure segment include minimum margin contracts and supply arrangements with municipalities and power generation facilities. Revenues for related sales are recognized monthly as natural gas is delivered and stand-ready service is provided, consistent with invoiced amounts and unbilled estimates. Estimated remaining performance obligations are as follows: Remaining Performance Obligations (in millions) 2020 2021 2022 2023 2024 Thereafter Total Piedmont $ 69 $ 64 $ 64 $ 61 $ 58 $ 372 $ 688 Commercial Renewables Commercial Renewables earns the majority of its revenues through long-term PPAs and generally sells all of its wind and solar facility output, electricity and RECs to customers. The majority of these PPAs have historically been accounted for as leases. For PPAs that are not accounted for as leases, the delivery of electricity and the delivery of RECs are considered separate performance obligations. The delivery of electricity is a performance obligation satisfied over time and represents generation and consumption of the electricity over the billing period, generally one month. The delivery of RECs is a performance obligation satisfied at a point in time and represents delivery of each REC generated by the wind or solar facility. The majority of self-generated RECs are bundled with energy in Duke Energy’s contracts and, as such, related revenues are recognized as energy is generated and delivered as that pattern is consistent with Duke Energy’s performance. Commercial Renewables recognizes revenue based on the energy generated and billed for the period, generally one month, at contractual rates (including unbilled estimates) according to the invoice practical expedient. Amounts are typically due within 30 days of invoice. Commercial Renewables also earns revenues from installation of distributed solar generation resources, which is primarily composed of EPC projects to deliver functioning solar power systems, generally completed within two to 12 months from commencement of construction. The installation of distributed solar generation resources is a performance obligation that is satisfied over time. Revenue from fixed-price EPC contracts is recognized using the input method as work is performed based on the estimated ratio of incurred costs to estimated total costs. Other The remainder of Duke Energy’s operations is presented as Other, which does not include material revenues from contracts with customers. Disaggregated Revenues For the Electric and Gas Utility and Infrastructure segments, revenue by customer class is most meaningful to Duke Energy as each respective customer class collectively represents unique customer expectations of service, generally has different energy and demand requirements, and operates under tailored, regulatory approved pricing structures. Additionally, each customer class is impacted differently by weather and a variety of economic factors including the level of population growth, economic investment, employment levels, and regulatory activities in each of Duke Energy’s jurisdictions. As such, analyzing revenues disaggregated by customer class allows Duke Energy to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. For the Commercial Renewables segment, the majority of revenues from contracts with customers are from selling all of the unit-contingent output at contractually defined pricing under long-term PPAs with consistent expectations regarding the timing and certainty of cash flows. Disaggregated revenues are presented as follows: Year Ended December 31, 2019 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 9,863 $ 3,044 $ 4,998 $ 2,144 $ 2,854 $ 733 $ 1,087 $ — General 6,431 2,244 2,935 1,368 1,567 451 802 — Industrial 3,071 1,215 934 675 259 147 774 — Wholesale 2,212 462 1,468 1,281 187 46 235 — Other revenues 770 276 548 317 231 80 89 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 22,347 $ 7,241 $ 10,883 $ 5,785 $ 5,098 $ 1,457 $ 2,987 $ — Gas Utilities and Infrastructure Residential $ 976 $ — $ — $ — $ — $ 315 $ — $ 661 Commercial 508 — — — — 130 — 378 Industrial 141 — — — — 19 — 122 Power Generation — — — — — — — 51 Other revenues 129 — — — — 19 — 110 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,754 $ — $ — $ — $ — $ 483 $ — $ 1,322 Commercial Renewables Revenue from contracts with customers $ 223 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 24 $ — $ — $ — $ — $ — $ — $ — Total revenue from contracts with customers $ 24,348 $ 7,241 $ 10,883 $ 5,785 $ 5,098 $ 1,940 $ 2,987 $ 1,322 Other revenue sources (a) $ 731 $ 154 $ 319 $ 172 $ 133 $ — $ 17 $ 59 Total revenues $ 25,079 $ 7,395 $ 11,202 $ 5,957 $ 5,231 $ 1,940 $ 3,004 $ 1,381 (a) Other revenue sources include revenues from leases, derivatives and alternative revenue programs that are not considered revenues from contracts with customers. Alternative revenue programs in certain jurisdictions include regulatory mechanisms that periodically adjust for over or under collection of related revenues. Year Ended December 31, 2018 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 9,587 $ 2,981 $ 4,785 $ 2,019 $ 2,766 $ 743 $ 1,076 $ — General 6,127 2,119 2,809 1,280 1,529 422 778 — Industrial 2,974 1,180 904 642 262 131 760 — Wholesale 2,324 508 1,462 1,303 159 57 298 — Other revenues 717 320 502 320 182 73 91 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 21,729 $ 7,108 $ 10,462 $ 5,564 $ 4,898 $ 1,426 $ 3,003 $ — Gas Utilities and Infrastructure Residential $ 1,000 $ — $ — $ — $ — $ 331 $ — $ 669 Commercial 514 — — — — 135 — 378 Industrial 147 — — — — 18 — 128 Power Generation — — — — — — — 54 Other revenues 139 — — — — 19 — 120 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,800 $ — $ — $ — $ — $ 503 $ — $ 1,349 Commercial Renewables Revenue from contracts with customers $ 209 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 19 $ — $ — $ — $ — $ 1 $ — $ — Total revenue from contracts with customers $ 23,757 $ 7,108 $ 10,462 $ 5,564 $ 4,898 $ 1,930 $ 3,003 $ 1,349 Other revenue sources (a) $ 764 $ 192 $ 266 $ 135 $ 123 $ 27 $ 56 $ 26 Total revenues $ 24,521 $ 7,300 $ 10,728 $ 5,699 $ 5,021 $ 1,957 $ 3,059 $ 1,375 (a) Other revenue sources include revenues from leases, derivatives and alternative revenue programs that are not considered revenues from contracts with customers. Alternative revenue programs in certain jurisdictions include regulatory mechanisms that periodically adjust for over or under collection of related revenues. IMPACT OF WEATHER AND THE TIMING OF BILLING PERIODS Revenues and costs are influenced by seasonal weather patterns. Peak sales of electricity occur during the summer and winter months, which results in higher revenue and cash flows during these periods. By contrast, lower sales of electricity occur during the spring and fall, allowing for scheduled plant maintenance. Residential and general service customers are more impacted by weather than industrial customers. Estimated weather impacts are based on actual current period weather compared to normal weather conditions. Normal weather conditions are defined as the long-term average of actual historical weather conditions. Heating degree days measure the variation in weather based on the extent the average daily temperature falls below a base temperature. Cooling degree days measure the variation in weather based on the extent the average daily temperature rises above the base temperature. Each degree of temperature below the base temperature counts as one heating degree day and each degree of temperature above the base temperature counts as one cooling degree day. The estimated impact of weather on earnings for Electric Utilities and Infrastructure is based on the temperature variances from a normal condition and customers' historic usage patterns. The methodology used to estimate the impact of weather does not consider all variables that may impact customer response to weather conditions, such as humidity in the summer or wind chill in the winter. The precision of this estimate may also be impacted by applying long-term weather trends to shorter-term periods. Gas Utilities and Infrastructure's costs and revenues are influenced by seasonal patterns due to peak natural gas sales occurring during the winter months as a result of space heating requirements. Residential customers are the most impacted by weather. There are certain regulatory mechanisms for the North Carolina, South Carolina, Tennessee, Ohio and Kentucky service territories that normalize the margins collected from certain customer classes during the winter. In North Carolina, rate design provides protection from both weather and other usage variations such as conservation, while South Carolina, Tennessee and Kentucky revenues are adjusted solely based on weather. Ohio primarily employs a fixed charge each month regardless of the season and usage. UNBILLED REVENUE Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy or natural gas delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills and meter reading schedules, and the impact of weather normalization or margin decoupling mechanisms. Unbilled revenues are included within Receivables and Receivables of VIEs on the Consolidated Balance Sheets as shown in the following table. December 31, (in millions) 2019 2018 Duke Energy $ 843 $ 896 Duke Energy Carolinas 298 313 Progress Energy 217 244 Duke Energy Progress 122 148 Duke Energy Florida 95 96 Duke Energy Ohio 1 2 Duke Energy Indiana 16 23 Piedmont 78 73 Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, CRC and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 18 for further information. These receivables for unbilled revenues are shown in the table below. December 31, (in millions) 2019 2018 Duke Energy Ohio $ 82 $ 86 Duke Energy Indiana 115 128

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS' EQUITY Basic EPS is computed by dividing net income available to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income available to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options and equity forward sale agreements, were exercised or settled. Duke Energy’s participating securities are RSUs that are entitled to dividends declared on Duke Energy common stock during the RSUs vesting periods. Dividends declared on preferred stock are recorded on the Consolidated Statements of Operations as a reduction of net income to arrive at net income available to Duke Energy common stockholders. Dividends accumulated on preferred stock are a reduction to net income used in the calculation of basic and diluted EPS. The following table presents Duke Energy’s basic and diluted EPS calculations, the weighted average number of common shares outstanding and common and preferred share dividends declared. Years Ended December 31, (in millions, except per share amounts) 2019 2018 2017 Income from continuing operations available to Duke Energy common stockholders excluding impact of participating securities and including accumulated preferred stock dividends $ 3,694 $ 2,642 $ 3,059 Weighted average common shares outstanding – basic and diluted 729 708 700 EPS from continuing operations available to Duke Energy common stockholders Basic and diluted $ 5.07 $ 3.73 $ 4.37 Potentially dilutive items excluded from the calculation (a) 2 2 2 Dividends declared per common share $ 3.75 $ 3.64 $ 3.49 Dividends declared on Series A preferred stock per depositary share $ 1.03 $ — $ — (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met. Common Stock In February 2018, Duke Energy filed a prospectus supplement and executed an Equity Distribution Agreement (EDA) under which it may sell up to $1 billion of its common stock through an ATM offering program, including an equity forward sales component. Under the terms of the EDA, Duke Energy was allowed to issue and sell shares of common stock. The existing ATM offering program expired in September 2019. In June 2018, Duke Energy marketed two separate tranches, each for 1.3 million shares, of common stock through equity forward transactions under the ATM program. In December 2018, Duke Energy physically settled these equity forwards by delivering 2.6 million shares of common stock in exchange for net proceeds of approximately $195 million . In March 2018, Duke Energy marketed an equity offering of 21.3 million shares of common stock through an Underwriting Agreement. In connection with the offering, Duke Energy entered into equity forward sale agreements. The equity forwards required Duke Energy to either physically settle the transactions by issuing 21.3 million shares in exchange for net proceeds at the then-applicable forward sale price specified by the agreements, or net settle in whole or in part through the delivery or receipt of cash or shares. In June 2018, Duke Energy physically settled one-half of the equity forwards by delivering approximately 10.6 million shares of common stock in exchange for net cash proceeds of approximately $781 million . In December 2018, Duke Energy physically settled the remaining equity forward by delivering 10.6 million shares of common stock in exchange for net cash proceeds of approximately $766 million . In March and April 2019, Duke Energy marketed two separate tranches, each for 1.1 million shares, of common stock through equity forward transactions under the ATM program. The first tranche had an initial forward price of $89.83 per share and the second tranche had an initial forward price of $88.82 per share. In May and June 2019, a third tranche of 1.6 million shares of common stock was marketed and had an initial forward price of $86.23 . The equity forwards required Duke Energy to either physically settle the transaction by issuing shares in exchange for net proceeds at the then-applicable forward sale price specified by the agreements or net settle in whole or in part through the delivery or receipt of cash or shares. The settlement alternative was at Duke Energy's election. In December 2019, Duke Energy physically settled the equity forwards by delivering 3.8 million shares of common stock in exchange for net cash proceeds of approximately $331 million . In November 2019, Duke Energy filed a prospectus supplement and executed an EDA under which it may sell up to $1.5 billion of its common stock through a new ATM offering program, including an equity forward sales component. Under the terms of the EDA, Duke Energy may issue and sell shares of common stock through September 2022. In November 2019, Duke Energy marketed an equity offering of 28.75 million shares of common stock through an Underwriting Agreement. In connection with the offering, Duke Energy entered into equity forward sales agreements with an initial forward price of $85.99 per share. The equity forward sales agreements require Duke Energy to either physically settle the transaction by issuing shares in exchange for net proceeds at the then-applicable forward sale price specified by the agreement, or net settle in whole or in part through the delivery or receipt of cash or shares. The settlement alternatives are at Duke Energy's election. Settlement of the forward sales agreements are expected to occur on or prior to December 31, 2020. If Duke Energy had elected to net share settle these contracts as of December 31, 2019, Duke Energy would have been required to deliver 1.6 million shares. For the years ended December 31, 2019 , and 2018 , Duke Energy issued 1.8 million and 2.2 million shares, respectively, through its DRIP with an increase in additional paid-in capital of approximately $160 million and $174 million , respectively. Preferred Stock On March 29, 2019, Duke Energy completed the issuance of 40 million depositary shares, each representing 1/1,000th share of its Series A Cumulative Redeemable Perpetual Preferred Stock, at a price of $25 per depositary share. The transaction resulted in net proceeds of $973 million after issuance costs with proceeds used for general corporate purposes and to reduce short-term debt. The preferred stock has a $25 liquidation preference per depositary share and earns dividends on a cumulative basis at a rate of 5.75% per annum. Dividends are payable quarterly in arrears on the 16th day of March, June, September and December, and began on June 16, 2019. The Series A Preferred Stock has no maturity or mandatory redemption date, is not redeemable at the option of the holders and includes separate call options. The first call option allows Duke Energy to call the Series A Preferred Stock at a redemption price of $25.50 per depositary share prior to June 15, 2024, in whole but not in part, at any time within 120 days after a ratings event where a rating agency amends, clarifies or changes the criteria it uses to assign equity credit for securities such as the preferred stock. The second call option allows Duke Energy to call the preferred stock, in whole or in part, at any time, on or after June 15, 2024, at a redemption price of $25 per depositary share. Duke Energy is also required to redeem all accumulated and unpaid dividends if either call option is exercised. On September 12, 2019, Duke Energy completed the issuance of 1 million shares of its Series B Fixed-Rate Reset Cumulative Redeemable Perpetual Preferred Stock, at a price of $1,000 per share. The transaction resulted in net proceeds of $989 million after issuance costs with proceeds being used to pay down short-term debt, repay at maturity $500 million senior notes due September 2019, and for general corporate purposes. The preferred stock has a $1,000 liquidation preference per share and earns dividends on a cumulative basis at an initial rate of 4.875% per annum. Dividends are payable semiannually in arrears on the 16th day of March and September, beginning on March 16, 2020. On September 16, 2024, the First Call Date, and any fifth anniversary of the First Call Date (each a Reset Date), the dividend rate will reset based on the then current five-year U.S. treasury rate plus a spread of 3.388% . The Series B Preferred Stock has no maturity or mandatory redemption date, is not redeemable at the option of the holders and includes separate call options. The first call option allows Duke Energy to call the Series B Preferred Stock at a redemption price of $1,020 per share, in whole but not in part, at any time within 120 days after a ratings event. The second call option allows Duke Energy to call the preferred stock, in whole or in part, on the First Call Date or any subsequent Reset Date at a redemption price in cash equal to $1,000 per share. Duke Energy is also required to redeem all accumulated and unpaid dividends if either call option is exercised. Dividends issued on its Series A and Series B Preferred Stock are subject to approval by the Board of Directors. However, the deferral of dividend payments on the preferred stock prohibits the declaration of common stock dividends. The Series A and Series B Preferred Stock rank, with respect to dividends and distributions upon liquidation or dissolution: • senior to Common Stock and to each other class or series of capital stock established after the original issue date of the Series A and Series B Preferred Stock that is expressly made subordinated to the Series A and Series B Preferred Stock; • on a parity with any class or series of capital stock established after the original issue date of the Series A and Series B Preferred Stock that is not expressly made senior or subordinated to the Series A or Series B Preferred Stock; • junior to any class or series of capital stock established after the original issue date of the Series A and Series B Preferred Stock that is expressly made senior to the Series A or Series B Preferred Stock; • junior to all existing and future indebtedness (including indebtedness outstanding under Duke Energy's credit facilities, unsecured senior notes, junior subordinated debentures and commercial paper) and other liabilities with respect to assets available to satisfy claims against Duke Energy; and • structurally subordinated to existing and future indebtedness and other liabilities of Duke Energy's subsidiaries and future preferred stock of subsidiaries. Holders of Series A and Series B Preferred Stock have no voting rights with respect to matters that generally require the approval of voting stockholders. The limited voting rights of holders of Series A and Series B Preferred Stock include the right to vote as a single class, respectively, on certain matters that may affect the preference or special rights of the preferred stock, except in the instance that Duke Energy elects to defer the payment of dividends for a total of six quarterly full dividend periods for Series A Preferred Stock or three semiannual full dividend periods for Series B Preferred Stock. If dividends are deferred for a cumulative total of six quarterly full dividend periods for Series A Preferred Stock or three semiannual full dividend periods for Series B Preferred Stock, whether or not for consecutive dividend periods, holders of the respective preferred stock have the right to elect two additional Board members to the Board of Directors.

Severance

Severance	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Severance	SEVERANCE During 2018, Duke Energy reviewed its operations and identified opportunities for improvement to better serve its customers. This operational review included the company's workforce strategy and staffing levels to ensure the company was staffed with the right skillsets and number of teammates to execute the long-term vision for Duke Energy. As such, Duke Energy extended voluntary and involuntary severance benefits to certain employees in specific areas as a part of workforce planning and digital transformation efforts. The following table presents the direct and allocated severance and related charges accrued for approximately 140 employees in 2019, 1,900 employees in 2018 and 100 employees in 2017 by the Duke Energy Registrants within Operation, maintenance and other on the Consolidated Statements of Operations. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Year Ended December 31, 2019 $ 16 $ 8 $ 6 $ 3 $ 3 $ — $ 1 $ 1 Year Ended December 31, 2018 187 102 69 52 17 6 7 2 Year Ended December 31, 2017 15 2 2 1 1 — 1 9 The table below presents the severance liability for past and ongoing severance plans including the plans described above. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at December 31, 2018 $ 205 $ 100 $ 51 $ 41 $ 9 $ 2 $ 2 $ — Provision/Adjustments 24 4 11 2 10 1 1 — Cash Reductions (188 ) (93 ) (49 ) (37 ) (12 ) (2 ) (1 ) — Balance at December 31, 2019 $ 41 $ 11 $ 13 $ 6 $ 7 $ 1 $ 2 $ —

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Duke Energy Corporation 2015 Long-Term Incentive Plan (the 2015 Plan) provides for the grant of stock-based compensation awards to employees and outside directors. The 2015 Plan reserves 10 million shares of common stock for issuance. Duke Energy has historically issued new shares upon exercising or vesting of share-based awards. However, Duke Energy may use a combination of new share issuances and open market repurchases for share-based awards that are exercised or vest in the future. Duke Energy has not determined with certainty the amount of such new share issuances or open market repurchases. The following table summarizes the total expense recognized by the Duke Energy Registrants, net of tax, for stock-based compensation. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy $ 65 $ 56 $ 43 Duke Energy Carolinas 24 20 15 Progress Energy 24 21 16 Duke Energy Progress 15 13 10 Duke Energy Florida 9 8 6 Duke Energy Ohio 5 4 3 Duke Energy Indiana 6 5 4 Piedmont 3 3 3 Duke Energy's pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table. Years Ended December 31, (in millions) 2019 2018 2017 RSU awards $ 44 $ 43 $ 41 Performance awards 45 35 27 Pretax stock-based compensation cost $ 89 $ 78 $ 68 Stock-based compensation costs capitalized 5 5 4 Stock-based compensation expense $ 84 $ 73 $ 64 Tax benefit associated with stock-based compensation expense $ 19 $ 17 $ 25 RESTRICTED STOCK UNIT AWARDS RSU awards generally vest over periods from immediate to three years . Fair value amounts are based on the market price of Duke Energy's common stock on the grant date. The following table includes information related to RSU awards. Years Ended December 31, 2019 2018 2017 Shares granted (in thousands) 571 649 583 Fair value (in millions) $ 51 $ 49 $ 47 The following table summarizes information about RSU awards outstanding. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2018 1,153 $ 77 Granted 571 89 Vested (631 ) 77 Forfeited (83 ) 82 Outstanding at December 31, 2019 1,010 83 RSU awards expected to vest 951 83 The total grant date fair value of shares vested during the years ended December 31, 2019 , 2018 and 2017 , was $49 million , $43 million and $42 million , respectively. At December 31, 2019 , Duke Energy had $30 million of unrecognized compensation cost, which is expected to be recognized over a weighted average period of 23 months . Prior to Duke Energy's acquisition of Piedmont, Piedmont had an incentive compensation plan that had a series of three-year performance and RSU awards for eligible officers and other participants. The 2016-2018 performance award cycle was approved subsequent to the Agreement and Plan of Merger between Duke Energy and Piedmont and was converted into a Duke Energy RSU award at the consummation of the acquisition. PERFORMANCE AWARDS Stock-based performance awards generally vest after three years if performance targets are met. The actual number of shares issued will range from zero to 200% of target shares, depending on the level of performance achieved. Performance awards contain performance conditions and a market condition. The performance conditions are based on Duke Energy's cumulative adjusted EPS and total incident case rate (total incident case rate is one of our key employee safety metrics). The market condition is based on TSR of Duke Energy relative to a predefined peer group. Relative TSR is valued using a path-dependent model that incorporates expected relative TSR into the fair value determination of Duke Energy’s performance-based share awards. The model uses three-year historical volatilities and correlations for all companies in the predefined peer group, including Duke Energy, to simulate Duke Energy’s relative TSR as of the end of the performance period. For each simulation, Duke Energy’s relative TSR associated with the simulated stock price at the end of the performance period plus expected dividends within the period results in a value per share for the award portfolio. The average of these simulations is the expected portfolio value per share. Actual life to date results of Duke Energy’s relative TSR for each grant are incorporated within the model. For performance awards granted in 2019 , the model used a risk-free interest rate of 2.5% , which reflects the yield on three-year Treasury bonds as of the grant date, and an expected volatility of 14.8% based on Duke Energy's historical volatility over three years using daily stock prices. The following table includes information related to stock-based performance awards. Years Ended December 31, 2019 2018 2017 Shares granted assuming target performance (in thousands) 320 372 461 Fair value (in millions) $ 27 $ 27 $ 37 The following table summarizes information about stock-based performance awards outstanding and assumes payout at the target level. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2018 1,117 $ 77 Granted 320 86 Vested (310 ) 75 Forfeited (18 ) 81 Outstanding at December 31, 2019 1,109 80 Stock-based performance awards expected to vest 1,080 80 The total grant date fair value of shares vested during the years ended December 31, 2019 , and 2018 , was $23 million and $13 million , respectively. No performance awards vested during the year ended December 31, 2017. At December 31, 2019 , Duke Energy had $27 million of unrecognized compensation cost, which is expected to be recognized over a weighted average period of 22 months .

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS DEFINED BENEFIT RETIREMENT PLANS Duke Energy and certain subsidiaries maintain, and the Subsidiary Registrants participate in, qualified, non-contributory defined benefit retirement plans. The Duke Energy plans cover most employees using a cash balance formula. Under a cash balance formula, a plan participant accumulates a retirement benefit consisting of pay credits based upon a percentage of current eligible earnings, age or age and years of service and interest credits. Certain employees are eligible for benefits that use a final average earnings formula. Under these final average earnings formulas, a plan participant accumulates a retirement benefit equal to the sum of percentages of their (i) highest three-year, four-year, or five-year average earnings, (ii) highest three-year, four-year, or five-year average earnings in excess of covered compensation per year of participation (maximum of 35 years ) or (iii) highest three-year average earnings times years of participation in excess of 35 years . Duke Energy also maintains, and the Subsidiary Registrants participate in, non-qualified, non-contributory defined benefit retirement plans that cover certain executives. The qualified and non-qualified, non-contributory defined benefit plans are closed to new participants. Duke Energy approved plan amendments to restructure its qualified non-contributory defined benefit retirement plans, effective January 1, 2018. The restructuring involved (i) the spin-off of the majority of inactive participants from two plans into a separate inactive plan and (ii) the merger of the active participant portions of such plans, along with a pension plan acquired as part of the Piedmont transaction, into a single active plan. Benefits offered to the plan participants remain unchanged except that the Piedmont plan's final average earnings formula was frozen as of December 31, 2017, and affected participants were moved into the active plan's cash balance formula. Actuarial gains and losses associated with the Inactive Plan will be amortized over the remaining life expectancy of the inactive participants. The longer amortization period lowered Duke Energy's 2018 pretax qualified pension plan expense by approximately $33 million . Duke Energy uses a December 31 measurement date for its defined benefit retirement plan assets and obligations. As a result of the application of settlement accounting due to total lump-sum benefit payments exceeding the settlement threshold (defined as the sum of the service cost and interest cost on projected benefit obligation components of net periodic pension costs) for one of its qualified pension plans, Duke Energy recognized settlement charges of $94 million , primarily as a regulatory asset within Other Noncurrent Assets on the Consolidated Balance Sheets as of December 31, 2019 (an immaterial amount was recorded in Other income and expenses, net within the Consolidated Statement of Operations). Settlement charges recognized by the Subsidiary Registrants as of December 31, 2019, which represent amounts allocated by Duke Energy for employees of the Subsidiary Registrants and allocated charges for their proportionate share of settlement charges for employees of Duke Energy’s shared services affiliate, were $53 million for Duke Energy Carolinas, $26 million for Progress Energy, $20 million for Duke Energy Progress, $6 million for Duke Energy Florida, $4 million for Duke Energy Indiana, $2 million for Duke Energy Ohio and $8 million for Piedmont. The settlement charges reflect the recognition of a pro-rata portion of previously unrecognized actuarial losses, equal to the percentage of reduction in the projected benefit obligation resulting from total lump - sum benefit payments as of December 31, 2019. Settlement charges recognized as a regulatory asset within Other Noncurrent Assets on the Consolidated Balance Sheets are amortized over the average remaining service period for participants in the plan. Amortization of settlement charges is disclosed in the tables below as a component of net periodic pension costs. Net periodic benefit costs disclosed in the tables below represent the cost of the respective benefit plan for the periods presented prior to capitalization of amounts reflected as Net property, plant and equipment, on the Consolidated Balance Sheets. Only the service cost component of net periodic benefit costs is eligible to be capitalized. The remaining non-capitalized portions of net periodic benefit costs are classified as either: (1) service cost, which is recorded in Operations, maintenance and other on the Consolidated Statements of Operations; or as (2) components of non-service cost, which is recorded in Other income and expenses, net, on the Consolidated Statements of Operations. Amounts presented in the tables below for the Subsidiary Registrants represent the amounts of pension and other post-retirement benefit cost allocated by Duke Energy for employees of the Subsidiary Registrants. Additionally, the Consolidated Statements of Operations of the Subsidiary Registrants also include allocated net periodic benefit costs for their proportionate share of pension and post-retirement benefit cost for employees of Duke Energy’s shared services affiliate that provide support to the Subsidiary Registrants. However, in the tables below, these amounts are only presented within the Duke Energy column (except for amortization of settlement charges). These allocated amounts are included in the governance and shared service costs discussed in Note 14 . Duke Energy’s policy is to fund amounts on an actuarial basis to provide assets sufficient to meet benefit payments to be paid to plan participants. Duke Energy does not anticipate making any contributions in 2020. The following table includes information related to the Duke Energy Registrants’ contributions to its qualified defined benefit pension plans. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Contributions Made: 2019 $ 77 $ 7 $ 57 $ 4 $ 53 $ 2 $ 2 $ 1 2018 141 46 45 25 20 — 8 — 2017 19 — — — — 4 — 11 QUALIFIED PENSION PLANS Components of Net Periodic Pension Costs Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 158 $ 49 $ 46 $ 26 $ 20 $ 4 $ 9 $ 5 Interest cost on projected benefit obligation 317 75 100 45 54 18 26 10 Expected return on plan assets (567 ) (147 ) (178 ) (88 ) (89 ) (28 ) (43 ) (22 ) Amortization of actuarial loss 108 24 39 15 24 4 8 8 Amortization of prior service credit (32 ) (8 ) (3 ) (2 ) (1 ) — (2 ) (9 ) Amortization of settlement charges 6 2 1 1 — 2 — — Net periodic pension costs (a)(b) $ (10 ) $ (5 ) $ 5 $ (3 ) $ 8 $ — $ (2 ) $ (8 ) Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 182 $ 58 $ 51 $ 29 $ 22 $ 5 $ 11 $ 7 Interest cost on projected benefit obligation 299 72 94 43 50 17 23 11 Expected return on plan assets (559 ) (147 ) (178 ) (85 ) (91 ) (28 ) (42 ) (22 ) Amortization of actuarial loss 132 29 44 21 23 5 10 11 Amortization of prior service credit (32 ) (8 ) (3 ) (2 ) (1 ) — (2 ) (10 ) Net periodic pension costs (a)(b) $ 22 $ 4 $ 8 $ 6 $ 3 $ (1 ) $ — $ (3 ) Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 159 $ 48 $ 45 $ 26 $ 19 $ 4 $ 9 $ 10 Interest cost on projected benefit obligation 328 79 100 47 53 18 26 14 Expected return on plan assets (545 ) (142 ) (167 ) (82 ) (85 ) (27 ) (42 ) (24 ) Amortization of actuarial loss 146 31 52 23 29 5 12 11 Amortization of prior service credit (24 ) (8 ) (3 ) (2 ) (1 ) (1 ) (2 ) (2 ) Settlement charge 12 — — — — — — 12 Other 8 2 2 1 1 — 1 1 Net periodic pension costs (a)(b) $ 84 $ 10 $ 29 $ 13 $ 16 $ (1 ) $ 4 $ 22 (a) Duke Energy amounts exclude $4 million , $5 million and $7 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $2 million , $2 million and $3 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase (decrease) $ (212 ) $ (156 ) $ (79 ) $ (59 ) $ (20 ) $ 12 $ 22 $ — Accumulated other comprehensive loss (income) Deferred income tax expense (benefit) $ 20 — 1 — (1 ) — — — Amortization of prior year service credit 1 — — — — — — — Amortization of prior year actuarial losses (15 ) — (2 ) — 3 — — — Net amount recognized in accumulated other comprehensive income $ 6 $ — $ (1 ) $ — $ 2 $ — $ — $ — Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase $ 298 $ 170 $ 40 $ 31 $ 9 $ 10 $ 30 $ 8 Accumulated other comprehensive (income) loss Deferred income tax expense $ (2 ) $ — $ 1 $ — $ — $ — $ — $ — Prior year service credit arising during the year 1 — — — — — — — Amortization of prior year actuarial losses 10 — (4 ) — — — — — Net amount recognized in accumulated other comprehensive income $ 9 $ — $ (3 ) $ — $ — $ — $ — $ — Reconciliation of Funded Status to Net Amount Recognized Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Obligation at prior measurement date $ 7,869 $ 1,954 $ 2,433 $ 1,125 $ 1,295 $ 435 $ 618 $ 264 Service cost 150 47 43 25 18 4 8 5 Interest cost 317 75 100 45 54 18 26 10 Actuarial loss 716 101 223 87 135 54 87 33 Transfers — 11 — — — — — — Benefits paid (731 ) (265 ) (191 ) (112 ) (78 ) (30 ) (46 ) (20 ) Obligation at measurement date $ 8,321 $ 1,923 $ 2,608 $ 1,170 $ 1,424 $ 481 $ 693 $ 292 Accumulated Benefit Obligation at measurement date $ 8,262 $ 1,923 $ 2,578 $ 1,170 $ 1,392 $ 471 $ 686 $ 292 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 8,233 $ 2,168 $ 2,606 $ 1,268 $ 1,322 $ 405 $ 611 $ 305 Employer contributions 77 7 57 4 53 2 2 1 Actual return on plan assets 1,331 342 426 204 218 66 100 49 Benefits paid (731 ) (265 ) (191 ) (112 ) (78 ) (30 ) (46 ) (20 ) Transfers — 11 — — — — — — Plan assets at measurement date $ 8,910 $ 2,263 $ 2,898 $ 1,364 $ 1,515 $ 443 $ 667 $ 335 Funded status of plan $ 589 $ 340 $ 290 $ 194 $ 91 $ (38 ) $ (26 ) $ 43 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Obligation at prior measurement date $ 8,448 $ 2,029 $ 2,637 $ 1,211 $ 1,410 $ 479 $ 669 $ 313 Service cost 174 56 49 28 21 5 10 7 Interest cost 299 72 94 43 50 17 23 11 Actuarial gain (485 ) (44 ) (204 ) (87 ) (114 ) (29 ) (29 ) (18 ) Transfers — — — — — — — (16 ) Benefits paid (567 ) (159 ) (143 ) (70 ) (72 ) (37 ) (55 ) (33 ) Obligation at measurement date $ 7,869 $ 1,954 $ 2,433 $ 1,125 $ 1,295 $ 435 $ 618 $ 264 Accumulated Benefit Obligation at measurement date $ 7,818 $ 1,954 $ 2,404 $ 1,125 $ 1,265 $ 425 $ 614 $ 264 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 9,003 $ 2,372 $ 2,814 $ 1,366 $ 1,429 $ 458 $ 684 $ 368 Employer contributions 141 46 45 25 20 — 8 — Actual return on plan assets (344 ) (91 ) (110 ) (53 ) (55 ) (16 ) (26 ) (14 ) Benefits paid (567 ) (159 ) (143 ) (70 ) (72 ) (37 ) (55 ) (33 ) Transfers — — — — — — — (16 ) Plan assets at measurement date $ 8,233 $ 2,168 $ 2,606 $ 1,268 $ 1,322 $ 405 $ 611 $ 305 Funded status of plan $ 364 $ 214 $ 173 $ 143 $ 27 $ (30 ) $ (7 ) $ 41 Amounts Recognized in the Consolidated Balance Sheets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Prefunded pension (a) $ 621 $ 340 $ 322 $ 194 $ 123 $ 38 $ 57 $ 43 Noncurrent pension liability (b) $ 32 $ — $ 32 $ — $ 32 $ 76 $ 83 $ — Net asset (liability) recognized $ 589 $ 340 $ 290 $ 194 $ 91 $ (38 ) $ (26 ) $ 43 Regulatory assets $ 1,972 $ 420 $ 717 $ 313 $ 404 $ 112 $ 204 $ 81 Accumulated other comprehensive (income) loss Deferred income tax benefit $ (23 ) $ — $ (1 ) $ — $ (1 ) $ — $ — $ — Prior service credit (3 ) — — — — — — — Net actuarial loss 111 — 3 — 3 — — — Net amounts recognized in accumulated other comprehensive loss $ 85 $ — $ 2 $ — $ 2 $ — $ — $ — Amounts to be recognized in net periodic pension costs in the next year Unrecognized net actuarial loss $ 135 $ 29 $ 43 $ 19 $ 24 $ 7 $ 10 $ 9 Unrecognized prior service credit (32 ) (8 ) (3 ) (2 ) (1 ) (1 ) (2 ) (9 ) December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Prefunded pension (a) $ 433 $ 214 $ 242 $ 143 $ 96 $ 24 $ 39 $ 41 Noncurrent pension liability (b) $ 69 $ — $ 69 $ — $ 69 $ 54 $ 46 $ — Net asset recognized $ 364 $ 214 $ 173 $ 143 $ 27 $ (30 ) $ (7 ) $ 41 Regulatory assets $ 2,184 $ 576 $ 796 $ 372 $ 424 $ 100 $ 182 $ 81 Accumulated other comprehensive (income) loss Deferred income tax benefit $ (43 ) $ — $ (2 ) $ — $ — $ — $ — $ — Prior service credit (4 ) — — — — — — — Net actuarial loss 126 — 5 — — — — — Net amounts recognized in accumulated other comprehensive loss $ 79 $ — $ 3 $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension costs in the next year Unrecognized net actuarial loss $ 97 $ 22 $ 37 $ 13 $ 24 $ 3 $ 5 $ 7 Unrecognized prior service credit $ (32 ) $ (8 ) $ (3 ) $ (2 ) $ (1 ) $ — $ (2 ) $ (9 ) (a) Included in Other within Other Noncurrent Assets on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets. Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets December 31, 2019 Duke Duke Energy Energy (in millions) Ohio Indiana Projected benefit obligation $ 155 $ 260 Accumulated benefit obligation 146 252 Fair value of plan assets 79 177 December 31, 2018 Duke Duke Duke Duke Progress Energy Energy Energy (in millions) Energy Energy Florida Ohio Indiana Projected benefit obligation $ 679 $ 679 $ 679 $ 123 $ 203 Accumulated benefit obligation 651 651 651 115 199 Fair value of plan assets 610 610 610 69 159 Assumptions Used for Pension Benefits Accounting The discount rate used to determine the current year pension obligation and following year’s pension expense is based on a bond selection-settlement portfolio approach. This approach develops a discount rate by selecting a portfolio of high quality corporate bonds that generate sufficient cash flow to provide for projected benefit payments of the plan. The selected bond portfolio is derived from a universe of non-callable corporate bonds rated Aa quality or higher. After the bond portfolio is selected, a single interest rate is determined that equates the present value of the plan’s projected benefit payments discounted at this rate with the market value of the bonds selected. The average remaining service period for participants in active plans and life expectancy of participants in inactive plans is 12 years for Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Florida, 13 years for Duke Energy Progress, Duke Energy Indiana and Duke Energy Ohio, and 9 years for Piedmont. The following tables present the assumptions or range of assumptions used for pension benefit accounting. December 31, 2019 2018 2017 Benefit Obligations Discount rate 3.30% 4.30% 3.60% Salary increase 3.50 % – 4.00% 3.50 % – 4.00% 3.50 % – 4.00% Net Periodic Benefit Cost Discount rate 4.30% 3.60% 4.10% Salary increase 3.50 % – 4.00% 3.50 % – 4.00% 4.00 % – 4.50% Expected long-term rate of return on plan assets 6.85% 6.50% 6.50 % – 6.75% Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Years ending December 31, 2020 $ 643 $ 167 $ 169 $ 89 $ 79 $ 37 $ 50 $ 28 2021 653 171 178 95 82 37 50 24 2022 649 177 176 92 84 37 49 22 2023 649 174 182 95 86 36 48 21 2024 638 168 184 96 87 35 48 20 2025-2029 2,851 714 871 419 448 156 220 87 NON-QUALIFIED PENSION PLANS The accumulated benefit obligation, which equals the projected benefit obligation for non-qualified pension plans, was $318 million for Duke Energy, $15 million for Duke Energy Carolinas, $110 million for Progress Energy, $32 million for Duke Energy Progress, $45 million for Duke Energy Florida, $4 million for Duke Energy Ohio, $3 million for Duke Energy Indiana and $4 million for Piedmont as of December 31, 2019 . Employer contributions, which equal benefits paid for non-qualified pension plans, were $25 million for Duke Energy, $2 million for Duke Energy Carolinas, $9 million for Progress Energy, $3 million for Duke Energy Progress and $3 million for Duke Energy Florida for the year ended December 31, 2019 . Employer contributions were not material for Duke Energy Ohio, Duke Energy Indiana or Piedmont for the year ended December 31, 2019 . Net periodic pension costs for non-qualified pension plans were not material for the years ended December 31, 2019 , 2018 or 2017 . OTHER POST-RETIREMENT BENEFIT PLANS Duke Energy provides, and the Subsidiary Registrants participate in, some health care and life insurance benefits for retired employees on a contributory and non-contributory basis. Employees are eligible for these benefits if they have met age and service requirements at retirement, as defined in the plans. The health care benefits include medical, dental and prescription drug coverage and are subject to certain limitations, such as deductibles and copayments. Duke Energy did not make any pre-funding contributions to its other post-retirement benefit plans during the years ended December 31, 2019 , 2018 or 2017 . Components of Net Periodic Other Post-Retirement Benefit Costs Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 4 $ 1 $ 1 $ — $ 1 $ — $ 1 $ — Interest cost on accumulated post-retirement benefit obligation 30 7 12 7 5 1 3 1 Expected return on plan assets (12 ) (7 ) — — — — — (1 ) Amortization of actuarial loss 4 2 1 — 1 — 4 — Amortization of prior service credit (19 ) (5 ) (8 ) (1 ) (7 ) (1 ) (1 ) (2 ) Net periodic post-retirement benefit costs (a)(b) $ 7 $ (2 ) $ 6 $ 6 $ — $ — $ 7 $ (2 ) Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 6 $ 1 $ 1 $ — $ 1 $ 1 $ 1 $ 1 Interest cost on accumulated post-retirement benefit obligation 28 7 12 6 6 1 3 1 Expected return on plan assets (13 ) (8 ) — — — — — (2 ) Amortization of actuarial loss 6 3 1 1 — — 4 — Amortization of prior service credit (19 ) (5 ) (8 ) (1 ) (7 ) (1 ) (1 ) (2 ) Net periodic post-retirement benefit costs (a)(b) $ 8 $ (2 ) $ 6 $ 6 $ — $ 1 $ 7 $ (2 ) Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 4 $ 1 $ — $ — $ — $ — $ — $ 1 Interest cost on accumulated post-retirement benefit obligation 34 8 13 7 6 1 3 1 Expected return on plan assets (14 ) (8 ) — — — — (1 ) (2 ) Amortization of actuarial loss (gain) 10 (2 ) 21 12 9 (2 ) (1 ) 1 Amortization of prior service credit (115 ) (10 ) (84 ) (54 ) (30 ) — (1 ) — Curtailment credit (c) (30 ) (4 ) (16 ) — (16 ) (2 ) (2 ) — Net periodic post-retirement benefit costs (a)(b) $ (111 ) $ (15 ) $ (66 ) $ (35 ) $ (31 ) $ (3 ) $ (2 ) $ 1 (a) Duke Energy amounts exclude $6 million , $7 million and $7 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $2 million , $2 million and $2 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (c) Curtailment credit resulted from a reduction in average future service of plan participants due to a plan amendment. Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase (decrease) $ (127 ) $ — $ (127 ) $ (82 ) $ (45 ) $ — $ (5 ) $ — Regulatory liabilities, net increase (decrease) $ (152 ) $ 1 $ (149 ) $ (93 ) $ (56 ) $ (1 ) $ (4 ) $ 3 Accumulated other comprehensive (income) loss Deferred income tax benefit $ — $ — $ — $ — $ — $ — $ — $ — Amortization of prior year actuarial gain (4 ) — — — — — — — Net amount recognized in accumulated other comprehensive income $ (4 ) $ — $ — $ — $ — $ — $ — $ — Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase (decrease) $ 137 $ — $ 133 $ 84 $ 49 $ — $ (5 ) $ 4 Regulatory liabilities, net increase (decrease) $ 154 $ (6 ) $ 149 $ 93 $ 56 $ 2 $ 3 $ — Accumulated other comprehensive (income) loss Deferred income tax benefit $ (1 ) $ — $ — $ — $ — $ — $ — $ — Amortization of prior year prior service credit 1 — — — — — — — Net amount recognized in accumulated other comprehensive income $ — $ — $ — $ — $ — $ — $ — $ — Reconciliation of Funded Status to Accrued Other Post-Retirement Benefit Costs Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 728 $ 174 $ 303 $ 166 $ 137 $ 29 $ 67 $ 30 Service cost 4 1 1 — 1 — 1 — Interest cost 30 7 12 7 5 1 3 1 Plan participants' contributions 16 3 6 3 2 1 2 — Actuarial losses 28 9 13 9 5 1 2 — Transfers — — — — — — — — Benefits paid (83 ) (19 ) (32 ) (17 ) (15 ) (3 ) (11 ) (1 ) Accumulated post-retirement benefit obligation at measurement date $ 723 $ 175 $ 303 $ 168 $ 135 $ 29 $ 64 $ 30 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 195 $ 115 $ — $ — $ — $ 8 $ 5 $ 29 Actual return on plan assets 32 20 (1 ) — — 1 — 6 Benefits paid (83 ) (19 ) (32 ) (17 ) (15 ) (3 ) (11 ) (1 ) Employer contributions 60 11 26 13 13 2 9 — Plan participants' contributions 16 3 6 3 2 1 2 — Plan assets at measurement date $ 220 $ 130 $ (1 ) $ (1 ) $ — $ 9 $ 5 $ 34 Funded status of plan $ (503 ) $ (45 ) $ (304 ) $ (169 ) $ (135 ) $ (20 ) $ (59 ) $ 4 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 813 $ 189 $ 342 $ 184 $ 156 $ 30 $ 78 $ 32 Service cost 6 1 1 — 1 1 1 1 Interest cost 28 7 12 6 6 1 3 1 Plan participants' contributions 18 3 6 4 3 1 2 — Actuarial losses (gains) (51 ) (8 ) (23 ) (9 ) (13 ) (2 ) (5 ) (1 ) Transfers — — — — — — — (1 ) Benefits paid (86 ) (18 ) (35 ) (19 ) (16 ) (2 ) (12 ) (2 ) Accumulated post-retirement benefit obligation at measurement date $ 728 $ 174 $ 303 $ 166 $ 137 $ 29 $ 67 $ 30 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 225 $ 133 $ — $ — $ — $ 7 $ 11 $ 31 Actual return on plan assets (8 ) (5 ) — — — — — (1 ) Benefits paid (86 ) (18 ) (35 ) (19 ) (16 ) (2 ) (12 ) (2 ) Employer contributions (reimbursements) 46 2 29 15 13 2 4 1 Plan participants' contributions 18 3 6 4 3 1 2 — Plan assets at measurement date $ 195 $ 115 $ — $ — $ — $ 8 $ 5 $ 29 Funded status of plan $ (533 ) $ (59 ) $ (303 ) $ (166 ) $ (137 ) $ (21 ) $ (62 ) $ (1 ) Amounts Recognized in the Consolidated Balance Sheets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current post-retirement liability (a) $ 9 $ — $ 5 $ 3 $ 2 $ 1 $ — $ — Noncurrent post-retirement liability (b) 494 45 299 166 133 19 59 (4 ) Total accrued post-retirement liability $ 503 $ 45 $ 304 $ 169 $ 135 $ 20 $ 59 $ (4 ) Regulatory assets $ 135 $ — $ 135 $ 82 $ 53 $ — $ 36 $ — Regulatory liabilities $ 149 $ 39 $ — $ — $ — $ 17 $ 63 $ 3 Accumulated other comprehensive (income) loss Deferred income tax expense $ 3 $ — $ — $ — $ — $ — $ — $ — Prior service credit (2 ) — — — — — — — Net actuarial gain (13 ) — — — — — — — Net amounts recognized in accumulated other comprehensive income $ (12 ) $ — $ — $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss $ 5 $ 3 $ 1 $ — $ 1 $ — $ — $ — Unrecognized prior service credit (14 ) (4 ) (3 ) (1 ) (2 ) (1 ) (1 ) (2 ) December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current post-retirement liability (a) $ 8 $ — $ 5 $ 3 $ 2 $ 2 $ — $ — Noncurrent post-retirement liability (b) 525 59 298 163 135 19 62 1 Total accrued post-retirement liability $ 533 $ 59 $ 303 $ 166 $ 137 $ 21 $ 62 $ 1 Regulatory assets $ 262 $ — $ 262 $ 164 $ 98 $ — $ 41 $ — Regulatory liabilities $ 301 $ 38 $ 149 $ 93 $ 56 $ 18 $ 67 $ — Accumulated other comprehensive (income) loss Deferred income tax expense $ 3 $ — $ — $ — $ — $ — $ — $ — Prior service credit (2 ) — — — — — — — Net actuarial gain (9 ) — — — — — — — Net amounts recognized in accumulated other comprehensive income $ (8 ) $ — $ — $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss (gain) $ 4 $ 2 $ 1 $ — $ — $ — $ — $ — Unrecognized prior service credit (19 ) (5 ) (7 ) (1 ) (6 ) (1 ) (1 ) (2 ) (a) Included in Other within Current Liabilities on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets. Assumptions Used for Other Post-Retirement Benefits Accounting The discount rate used to determine the current year other post-retirement benefits obligation and following year’s other post-retirement benefits expense is based on a bond selection-settlement portfolio approach. This approach develops a discount rate by selecting a portfolio of high quality corporate bonds that generate sufficient cash flow to provide for projected benefit payments of the plan. The selected bond portfolio is derived from a universe of non-callable corporate bonds rated Aa quality or higher. After the bond portfolio is selected, a single interest rate is determined that equates the present value of the plan’s projected benefit payments discounted at this rate with the market value of the bonds selected. The average remaining service period of active covered employees is eight years for Duke Energy and Duke Energy Carolinas, seven years for Progress Energy, Duke Energy Florida, and Duke Energy Ohio, and six years for Duke Energy Progress, Duke Energy Indiana, and Piedmont. The following tables present the assumptions used for other post-retirement benefits accounting. December 31, 2019 2018 2017 Benefit Obligations Discount rate 3.30 % 4.30 % 3.60 % Net Periodic Benefit Cost Discount rate 4.30 % 3.60 % 4.10 % Expected long-term rate of return on plan assets 6.85 % 6.50 % 6.50 % Assumed tax rate 23 % 35 % 35 % Assumed Health Care Cost Trend Rate December 31, 2019 2018 Health care cost trend rate assumed for next year 6.00 % 6.50 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that rate reaches ultimate trend 2026 2024 Sensitivity to Changes in Assumed Health Care Cost Trend Rates Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 1-Percentage Point Increase Effect on total service and interest costs $ 1 $ — $ 1 $ 1 $ — $ — $ — $ — Effect on post-retirement benefit obligation 22 5 9 5 4 1 2 1 1-Percentage Point Decrease Effect on total service and interest costs (1 ) — (1 ) (1 ) — — — — Effect on post-retirement benefit obligation (20 ) (5 ) (8 ) (4 ) (4 ) (1 ) (2 ) (1 ) Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Years ending December 31, 2020 $ 76 $ 18 $ 29 $ 16 $ 13 $ 4 $ 8 $ 2 2021 70 17 28 15 13 3 7 2 2022 66 16 27 14 12 3 7 2 2023 63 15 25 14 12 3 6 2 2024 59 15 24 13 11 3 6 2 2025-2029 246 60 101 55 46 11 23 11 PLAN ASSETS Description and Allocations Duke Energy Master Retirement Trust Assets for both the qualified pension and other post-retirement benefits are maintained in the Duke Energy Master Retirement Trust. Approximately 98% of the Duke Energy Master Retirement Trust assets were allocated to qualified pension plans and approximately 2% were allocated to other post-retirement plans (comprised of 401(h) accounts), as of December 31, 2019 , and 2018 . The investment objective of the Duke Energy Master Retirement Trust is to invest in a diverse portfolio of assets that is expected to generate positive surplus return over time (i.e. asset growth greater than liability growth) subject to a prudent level of portfolio risk, for the purpose of enhancing the security of benefits for plan participants. As of December 31, 2019 , Duke Energy assumes pension and other post-retirement plan assets will generate a long-term rate of return of 6.85% . The expected long-term rate of return was developed using a weighted average calculation of expected returns based primarily on future expected returns across asset classes considering the use of active asset managers, where applicable. The asset allocation targets were set after considering the investment objective and the risk profile. Equity securities are held for their higher expected returns. Debt securities are primarily held to hedge the qualified pension plan liability. Real assets, return seeking fixed income, hedge funds and other global securities are held for diversification. Investments within asset classes are diversified to achieve broad market participation and reduce the impact of individual managers or investments. Effective January 1, 2019, the target asset allocation for the Duke Energy Retirement Master Trust is 58% liability hedging assets and 42% return-seeking assets. Duke Energy periodically reviews its asset allocation targets, and over time, as the funded status of the benefit plans increase, the level of asset risk relative to plan liabilities may be reduced to better manage Duke Energy's benefit plan liabilities and reduce funded status volatility. The Duke Energy Master Retirement Trust is authorized to engage in the lending of certain plan assets. Securities lending is an investment management enhancement that utilizes certain existing securities of the Duke Energy Master Retirement Trust to earn additional income. Securities lending involves the loaning of securities to approved parties. In return for the loaned securities, the Duke Energy Master Retirement Trust receives collateral in the

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Tax Act On December 22, 2017, President Trump signed the Tax Act into law. Among other provisions, the Tax Act lowered the corporate federal income tax rate from 35% to 21%, limits interest deductions outside of regulated utility operations, requires the normalization of excess deferred taxes associated with property under the average rate assumption method as a prerequisite to qualifying for accelerated depreciation and repealed the federal manufacturing deduction. The Tax Act also repealed the corporate AMT and stipulates a refund of 50% of remaining AMT credit carryforwards (to the extent the credits exceed regular tax for the year) for tax years 2018, 2019, and 2020, with all remaining AMT credits to be refunded in tax year 2021. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin (SAB) 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act, which provides guidance on accounting for the Tax Act’s impact. SAB 118 provides a measurement period, which in no case should extend beyond one year from the Tax Act enactment date, during which a company acting in good faith may complete the accounting for the impacts of the Tax Act under ASC Topic 740. In accordance with SAB 118, a company must reflect the income tax effects of the Tax Act in the reporting period in which the accounting under ASC Topic 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete, a company can determine a reasonable estimate for those effects and record a provisional estimate in the financial statements in the first reporting period in which a reasonable estimate can be determined. As of December 31, 2018, the accounting for the effects of the Tax Act was complete. During the year ended December 31, 2018, Duke Energy recorded the following measurement period adjustments in accordance with SAB 118: • Additional tax expense of $23 million related to the completion of the analysis of Duke Energy’s existing regulatory liability related to deferred taxes; • A $10 million tax benefit for the remeasurement of deferred tax assets and deferred tax liabilities primarily related to the guidance on bonus depreciation issued by the IRS in August 2018, affecting the computation of the Company's 2017 Federal income tax liability; • Additional tax expense of $7 million related to the portion of the deferred tax asset as of December 31, 2017, that represents nondeductible long-term incentives under the Tax Act’s limitation on the deductibility of executive compensation; and • During the fourth quarter of 2018, the Company released the $76 million valuation allowance that it recorded in the first quarter of 2018 as a result of additional guidance published by the IRS that stated refundable AMT credits would not be subject to sequestration. • The majority of Duke Energy’s operations are regulated and it is expected that the Subsidiary Registrants will ultimately pass on the savings associated with the amount representing the remeasurement of deferred tax balances related to regulated operations to customers. For Duke Energy's regulated operations, where the reduction is expected to be returned to customers in future rates, the remeasurement has been deferred as a regulatory liability. During 2018, Duke Energy recorded an additional regulatory liability of $83 million , representing the revaluation of those deferred tax balances. The Subsidiary Registrants continue to respond to requests from regulators in various jurisdictions to determine the timing and magnitude of savings they will pass on to customers. In addition, during 2018, Duke Energy reclassified $573 million of AMT credit carryforwards from noncurrent deferred tax liabilities to a current federal income tax receivable. In 2019, Duke Energy received a refund of $573 million related to AMT credit carryforwards based on the filing of Duke Energy's 2018 income tax return in 2019 and reclassified $286 million of AMT credits from noncurrent deferred tax liabilities to a current federal income tax receivable. Income Tax Expense Components of Income Tax Expense Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current income taxes Federal $ (299 ) $ 164 $ (173 ) $ (36 ) $ (43 ) $ (41 ) $ (23 ) $ (92 ) State 10 13 (7 ) (3 ) 18 (1 ) 1 (1 ) Foreign 2 — — — — — — — Total current income taxes (287 ) 177 (180 ) (39 ) (25 ) (42 ) (22 ) (93 ) Deferred income taxes Federal 855 175 422 220 153 77 128 133 State (38 ) (37 ) 17 (18 ) 27 5 28 3 Total deferred income taxes (a) 817 138 439 202 180 82 156 136 ITC amortization (11 ) (4 ) (6 ) (6 ) — — — — Income tax expense from continuing operations 519 311 253 157 155 40 134 43 Tax benefit from discontinued operations (2 ) — — — — — — — Total income tax expense included in Consolidated Statements of Operations $ 517 $ 311 $ 253 $ 157 $ 155 $ 40 $ 134 $ 43 (a) Total deferred income taxes includes the generation of tax credit carryforwards of $8 million at Duke Energy Carolinas. In addition, total deferred income taxes includes utilization of NOL carryforwards and tax credit carryforwards of $243 million at Progress Energy, $35 million at Duke Energy Progress, $152 million at Duke Energy Florida, $25 million at Duke Energy Ohio, $60 million at Duke Energy Indiana, $90 million at Piedmont and $775 million at Duke Energy. Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current income taxes Federal $ (647 ) $ (8 ) $ (135 ) $ (71 ) $ (49 ) $ 20 $ 29 $ 67 State (11 ) 6 (5 ) (5 ) (10 ) (1 ) 3 1 Foreign 3 — — — — — — — Total current income taxes (655 ) (2 ) (140 ) (76 ) (59 ) 19 32 68 Deferred income taxes Federal 1,064 299 341 256 115 21 74 (36 ) State 49 11 20 (17 ) 45 3 22 5 Total deferred income taxes (a)(b) 1,113 310 361 239 160 24 96 (31 ) ITC amortization (10 ) (5 ) (3 ) (3 ) — — — — Income tax expense from continuing operations 448 303 218 160 101 43 128 37 Tax benefit from discontinued operations (26 ) — — — — — — — Total income tax expense included in Consolidated Statements of Operations $ 422 $ 303 $ 218 $ 160 $ 101 $ 43 $ 128 $ 37 (a) Includes benefits of NOL carryforwards and tax credit carryforwards of $22 million at Duke Energy Carolinas, $293 million at Progress Energy, $59 million at Duke Energy Progress, $219 million at Duke Energy Florida, $17 million at Duke Energy Ohio, $21 million at Duke Energy Indiana and $39 million at Piedmont. In addition, total deferred income taxes includes utilization of NOL carryforwards and tax credit carryforwards of $18 million at Duke Energy. (b) For the year ended December 31, 2018, the Company has revised the December 31, 2017, estimates of the income tax effects of the Tax Act, in accordance with SAB 118. See the Statutory Rate Reconciliation section below for additional information on the Tax Act's impact on income tax expense. Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current income taxes Federal $ (247 ) $ 221 $ (436 ) $ (95 ) $ (188 ) $ (37 ) $ 128 $ (90 ) State 4 20 (5 ) 2 (11 ) 2 21 (3 ) Foreign 3 — — — — — — — Total current income taxes (240 ) 241 (441 ) (93 ) (199 ) (35 ) 149 (93 ) Deferred income taxes Federal 1,344 381 664 378 194 99 138 147 State 102 35 44 10 51 (4 ) 14 8 Total deferred income taxes (a)(b) 1,446 416 708 388 245 95 152 155 ITC amortization (10 ) (5 ) (3 ) (3 ) — (1 ) — — Income tax expense from continuing operations 1,196 652 264 292 46 59 301 62 Tax benefit from discontinued operations (6 ) — — — — — — — Total income tax expense included in Consolidated Statements of Operations $ 1,190 $ 652 $ 264 $ 292 $ 46 $ 59 $ 301 $ 62 (a) Includes utilization of NOL carryforwards and tax credit carryforwards of $428 million at Duke Energy, $74 million at Progress Energy, $36 million at Duke Energy Florida, $17 million at Duke Energy Ohio, $42 million at Duke Energy Indiana and $79 million at Piedmont. In addition, total deferred income taxes includes benefits of NOL carryforwards and tax credit carryforwards of $10 million at Duke Energy Carolinas and $1 million at Duke Energy Progress. (b) As a result of the Tax Act, Duke Energy's deferred tax assets and liabilities were revalued as of December 31, 2017. See the Statutory Rate Reconciliation section below for additional information on the Tax Act's impact on income tax expense. Duke Energy Income from Continuing Operations before Income Taxes Years Ended December 31, (in millions) 2019 2018 2017 Domestic (a) $ 4,053 $ 3,018 $ 4,207 Foreign 44 55 59 Income from continuing operations before income taxes $ 4,097 $ 3,073 $ 4,266 (a) Includes a $16 million expense in 2017 related to the Tax Act impact on equity earnings included within Equity in earnings of unconsolidated affiliates on the Consolidated Statement of Operations. Statutory Rate Reconciliation The following tables present a reconciliation of income tax expense at the U.S. federal statutory tax rate to the actual tax expense from continuing operations. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Income tax expense, computed at the statutory rate of 21% $ 860 $ 360 $ 332 $ 202 $ 178 $ 59 $ 120 $ 51 State income tax, net of federal income tax effect (22 ) (19 ) 8 (17 ) 35 3 22 2 Amortization of excess deferred income tax (121 ) (29 ) (64 ) (10 ) (54 ) (12 ) (6 ) (10 ) AFUDC equity income (52 ) (9 ) (14 ) (13 ) (1 ) (3 ) (3 ) — AFUDC equity depreciation 34 19 10 5 5 1 4 — Renewable energy PTCs (120 ) — — — — — — — Other tax credits (23 ) (11 ) (9 ) (7 ) (2 ) (1 ) (1 ) (1 ) Tax true up (64 ) (9 ) (8 ) (3 ) (5 ) (7 ) (1 ) — Other items, net 27 9 (2 ) — (1 ) — (1 ) 1 Income tax expense from continuing operations $ 519 $ 311 $ 253 $ 157 $ 155 $ 40 $ 134 $ 43 Effective tax rate 12.7 % 18.1 % 16.0 % 16.3 % 18.3 % 14.3 % 23.5 % 17.6 % Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Income tax expense, computed at the statutory rate of 21% $ 645 $ 288 $ 263 $ 174 $ 137 $ 46 $ 109 $ 35 State income tax, net of federal income tax effect 30 14 13 (17 ) 28 2 20 4 Amortization of excess deferred income tax (61 ) — (55 ) (1 ) (54 ) (3 ) (2 ) — AFUDC equity income (42 ) (15 ) (22 ) (12 ) (10 ) (2 ) (2 ) — AFUDC equity depreciation 31 18 9 5 4 1 4 — Renewable energy PTCs (129 ) — — — — — — — Other tax credits (28 ) (7 ) (13 ) (5 ) (8 ) (1 ) (1 ) (3 ) Tax Act (a) 20 1 25 19 — 2 — — Other items, net (18 ) 4 (2 ) (3 ) 4 (2 ) — 1 Income tax expense from continuing operations $ 448 $ 303 $ 218 $ 160 $ 101 $ 43 $ 128 $ 37 Effective tax rate 14.6 % 22.1 % 17.4 % 19.3 % 15.4 % 19.6 % 24.6 % 22.3 % (a) For the year ended December 31, 2018, the Company revised the December 31, 2017 estimates of the income tax effects of the Tax Act, in accordance with SAB 118. Amounts primarily include but are not limited to items that are excluded for ratemaking purposes related certain wholesale fixed rate contracts, remeasurement of nonregulated net deferred tax liabilities, Federal NOLs, and valuation allowance on foreign tax credits. Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Income tax expense, computed at the statutory rate of 35% $ 1,493 $ 653 $ 536 $ 353 $ 265 $ 88 $ 229 $ 70 State income tax, net of federal income tax effect 69 36 25 8 26 (1 ) 23 3 AFUDC equity income (81 ) (37 ) (32 ) (17 ) (16 ) (4 ) (8 ) — Renewable energy PTCs (132 ) — — — — — — — Tax Act (a) (112 ) 15 (246 ) (40 ) (226 ) (23 ) 55 (12 ) Tax true up (52 ) (24 ) (19 ) (13 ) (7 ) (5 ) (6 ) — Other items, net 11 9 — 1 4 4 8 1 Income tax expense from continuing operations $ 1,196 $ 652 $ 264 $ 292 $ 46 $ 59 $ 301 $ 62 Effective tax rate 28.0 % 34.9 % 17.2 % 29.0 % 6.1 % 23.4 % 46.0 % 30.8 % (a) Amounts primarily include but are not limited to items that are excluded for ratemaking purposes related to abandoned or impaired assets, certain wholesale fixed rate contracts, remeasurement of nonregulated net deferred tax liabilities, Federal NOLs, and valuation allowance on foreign tax credits. Valuation allowances have been established for certain state NOL carryforwards and state income tax credits that reduce deferred tax assets to an amount that will be realized on a more-likely-than-not basis. The net change in the total valuation allowance is included in State income tax, net of federal income tax effect, in the above tables. Valuation allowances have been established for foreign tax credits that reduce deferred tax assets to an amount that will be realized on a more-likely-than-not basis. The net change in the total valuation allowance is included in Tax Act in the above tables. DEFERRED TAXES Net Deferred Income Tax Liability Components December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Deferred credits and other liabilities $ 125 $ 24 $ 25 $ 49 $ — $ 14 $ 5 $ 22 Lease obligations 462 72 193 92 102 5 17 6 Pension, post-retirement and other employee benefits 303 (5 ) 88 38 44 17 27 (3 ) Progress Energy merger purchase accounting adjustments (a) 389 — — — — — — — Tax credits and NOL carryforwards 3,925 262 486 176 253 16 176 19 Regulatory liabilities and deferred credits — — — — — 36 52 42 Investments and other assets — — — — — 10 — 2 Other 97 5 8 3 2 8 1 6 Valuation allowance (587 ) — — — — — — — Total deferred income tax assets 4,714 358 800 358 401 106 278 94 Investments and other assets (1,664 ) (981 ) (577 ) (390 ) (190 ) — (12 ) — Accelerated depreciation rates (10,813 ) (3,254 ) (3,798 ) (1,918 ) (1,913 ) (1,028 ) (1,416 ) (802 ) Regulatory assets and deferred debits, net (1,115 ) (44 ) (887 ) (438 ) (477 ) — — — Total deferred income tax liabilities (13,592 ) (4,279 ) (5,262 ) (2,746 ) (2,580 ) (1,028 ) (1,428 ) (802 ) Net deferred income tax liabilities $ (8,878 ) $ (3,921 ) $ (4,462 ) $ (2,388 ) $ (2,179 ) $ (922 ) $ (1,150 ) $ (708 ) (a) Primarily related to finance lease obligations and debt fair value adjustments. The following table presents the expiration of tax credits and NOL carryforwards. December 31, 2019 (in millions) Amount Expiration Year General Business Credits $ 1,821 2024 — 2039 AMT credits 286 Refundable by 2021 Federal NOL carryforwards (a) (f) 169 2024 — Indefinite Capital loss carryforward (e) 87 2024 State carryforwards and credits (b) (f) 303 2020 — Indefinite Foreign NOL carryforwards (c) 12 2027 — 2037 Foreign Tax Credits (d) 1,237 2024 — 2027 Charitable contribution carryforwards 10 2020 — 2024 Total tax credits and NOL carryforwards $ 3,925 (a) A valuation allowance of $4 million has been recorded on the Federal NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (b) A valuation allowance of $97 million has been recorded on the state NOL and credit carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (c) A valuation allowance of $12 million has been recorded on the foreign NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (d) A valuation allowance of $387 million has been recorded on the foreign tax credits, as presented in the Net Deferred Income Tax Liability Components table. (e) A valuation allowance of $87 million has been recorded on the Federal capital loss carryforward, as presented in the Net Deferred Income Tax Liability Components table. (f) Indefinite carryforward for Federal NOLs, and NOLs for states that have adopted the Tax Act's NOL provisions, generated in tax years beginning after December 31, 2017. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Deferred credits and other liabilities $ 164 $ 64 $ 35 $ 53 $ — $ 17 $ 6 $ 17 Finance lease obligations 60 26 — — — — 2 — Pension, post-retirement and other employee benefits 347 24 110 47 58 16 24 (1 ) Progress Energy merger purchase accounting adjustments (a) 483 — — — — — — — Tax credits and NOL carryforwards 4,580 257 693 215 363 42 237 110 Regulatory liabilities and deferred credits — — — — — 56 — 48 Investments and other assets — — — — — 18 — 16 Other 25 6 5 5 — 1 (1 ) — Valuation allowance (484 ) — — — — — — — Total deferred income tax assets 5,175 377 843 320 421 150 268 190 Investments and other assets (1,317 ) (795 ) (430 ) (272 ) (163 ) — (5 ) — Accelerated depreciation rates (10,124 ) (3,207 ) (3,369 ) (1,735 ) (1,670 ) (967 ) (1,081 ) (733 ) Regulatory assets and deferred debits, net (1,540 ) (64 ) (985 ) (432 ) (574 ) — (191 ) — Other — — — — — — — (8 ) Total deferred income tax liabilities (12,981 ) (4,066 ) (4,784 ) (2,439 ) (2,407 ) (967 ) (1,277 ) (741 ) Net deferred income tax liabilities $ (7,806 ) $ (3,689 ) $ (3,941 ) $ (2,119 ) $ (1,986 ) $ (817 ) $ (1,009 ) $ (551 ) (a) Primarily related to finance lease obligations and debt fair value adjustments. UNRECOGNIZED TAX BENEFITS The following tables present changes to unrecognized tax benefits. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unrecognized tax benefits – January 1 $ 24 $ 6 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 Unrecognized tax benefit increases 105 2 1 1 — — — — Gross decreases – tax positions in prior periods (3 ) — (1 ) (1 ) — — — — Total changes 102 2 — — — — — — Unrecognized tax benefits – December 31 $ 126 $ 8 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unrecognized tax benefits – January 1 $ 25 $ 5 $ 5 $ 5 $ 5 $ 1 $ 1 $ 3 Unrecognized tax benefits increases (decreases) Gross decreases – tax positions in prior periods (2 ) (1 ) — — (4 ) — — — Gross increases – tax positions in prior periods 7 2 4 1 2 — — 1 Decreases due to settlements (6 ) — — — — — — — Total changes (1 ) 1 4 1 (2 ) — — 1 Unrecognized tax benefits – December 31 $ 24 $ 6 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unrecognized tax benefits – January 1 $ 17 $ 1 $ 2 $ 2 $ 4 $ 4 $ — $ — Unrecognized tax benefits increases (decreases) Gross increases – tax positions in prior periods 12 4 3 3 1 1 1 3 Gross decreases – tax positions in prior periods (4 ) — — — — (4 ) — — Total changes 8 4 3 3 1 (3 ) 1 3 Unrecognized tax benefits – December 31 $ 25 $ 5 $ 5 $ 5 $ 5 $ 1 $ 1 $ 3 The following table includes additional information regarding the Duke Energy Registrants' unrecognized tax benefits at December 31, 2019 . It is reasonably possible that Duke Energy will reflect a $3 million decrease in unrecognized tax benefits within the next 12 months. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Amount that if recognized, would affect the effective tax rate or regulatory liability (a) $ 122 $ 8 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 (a) The Duke Energy Registrants are unable to estimate the specific amounts that would affect the effective tax rate versus the regulatory liability. OTHER TAX MATTERS The following tables include interest recognized in the Consolidated Statements of Operations and the Consolidated Balance Sheets. Year Ended December 31, 2019 Duke Duke Progress Energy (in millions) Energy Energy Progress Piedmont Net interest income recognized related to income taxes $ 16 $ 1 $ 1 $ — Interest receivable related to income taxes 1 — — — Interest payable related to income taxes 1 — — 1 Year Ended December 31, 2018 Duke Duke Progress Energy (in millions) Energy Energy Progress Net interest income recognized related to income taxes $ 2 $ — $ — Interest payable related to income taxes 3 1 1 Year Ended December 31, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Net interest income recognized related to income taxes $ — $ — $ 1 $ — $ 1 Net interest expense recognized related to income taxes — 2 — — — Interest payable related to income taxes 5 25 1 1 — Duke Energy and its subsidiaries are no longer subject to U.S. federal examination for years before 2016. With few exceptions, Duke Energy and its subsidiaries are no longer subject to state, local or non-U.S. income tax examinations by tax authorities for years before 2016.

Other Income and Expenses, Net

Other Income and Expenses, Net	12 Months Ended
	Dec. 31, 2019
Other Income and Expenses [Abstract]
Other Income and Expenses, Net	OTHER INCOME AND EXPENSES, NET The components of Other income and expenses, net on the Consolidated Statements of Operations are as follows. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Interest income $ 31 $ 1 $ 11 $ — $ 11 $ 10 $ 10 $ 1 AFUDC equity 139 42 66 60 6 13 18 — Post in-service equity returns 29 20 7 7 — 1 — — Nonoperating income, other 231 88 57 33 31 — 13 19 Other income and expense, net $ 430 $ 151 $ 141 $ 100 $ 48 $ 24 $ 41 $ 20 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Interest income $ 20 $ 1 $ 18 $ 1 $ 18 $ 7 $ 9 $ 1 AFUDC equity 221 73 104 57 47 11 32 — Post in-service equity returns 15 9 5 5 — 1 — — Nonoperating income, other 143 70 38 24 21 4 4 13 Other income and expense, net $ 399 $ 153 $ 165 $ 87 $ 86 $ 23 $ 45 $ 14 Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Interest income $ 13 $ 2 $ 6 $ 2 $ 5 $ 6 $ 8 $ — AFUDC equity 237 106 92 47 45 11 28 — Post in-service equity returns 40 28 12 12 — — — — Nonoperating income, other 218 63 99 54 46 6 11 (11 ) Other income and expense, net $ 508 $ 199 $ 209 $ 115 $ 96 $ 23 $ 47 $ (11 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on subsequent events related to the adoption of the new credit losses accounting standard, regulatory matters and debt and credit facilities, see Notes 1, 4 and 7, respectively.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	QUARTERLY FINANCIAL DATA (UNAUDITED) DUKE ENERGY Quarterly EPS amounts may not sum to the full-year total due to changes in the weighted average number of common shares outstanding and rounding. First Second Third Fourth (in millions, except per share data) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 6,163 $ 5,873 $ 6,940 $ 6,103 $ 25,079 Operating income 1,373 1,298 1,929 1,109 5,709 Income from continuing operations 893 748 1,323 614 3,578 Loss from discontinued operations, net of tax — — — (7 ) (7 ) Net income 893 748 1,323 607 3,571 Net income available to Duke Energy Corporation common stockholders 900 820 1,327 660 3,707 Earnings per share: Income from continuing operations available to Duke Energy Corporation common stockholders Basic and diluted $ 1.24 $ 1.12 $ 1.82 $ 0.89 $ 5.07 Loss from discontinued operations attributable to Duke Energy Corporation common stockholders Basic and diluted $ — $ — $ — $ (0.01 ) $ (0.01 ) Net income available to Duke Energy Corporation common stockholders Basic and diluted $ 1.24 $ 1.12 $ 1.82 $ 0.88 $ 5.06 2018 Operating revenues $ 6,135 $ 5,643 $ 6,628 $ 6,115 $ 24,521 Operating income 1,256 979 1,579 871 4,685 Income from continuing operations 622 507 1,062 434 2,625 (Loss) Income from discontinued operations, net of tax — (5 ) 4 20 19 Net income 622 502 1,066 454 2,644 Net income attributable to Duke Energy Corporation 620 500 1,082 464 2,666 Earnings per share: Income from continuing operations attributable to Duke Energy Corporation common stockholders Basic and diluted $ 0.88 $ 0.72 $ 1.51 $ 0.62 $ 3.73 (Loss) Income from discontinued operations attributable to Duke Energy Corporation common stockholders Basic and diluted $ — $ (0.01 ) $ — $ 0.03 $ 0.03 Net income attributable to Duke Energy Corporation common stockholders Basic and diluted $ 0.88 $ 0.71 $ 1.51 $ 0.65 $ 3.76 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Impairment Charges (see Notes 4 and 13) $ — $ — $ 25 $ (14 ) $ 11 Total $ — $ — $ 25 $ (14 ) $ 11 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (17 ) $ (20 ) $ (16 ) $ (31 ) $ (84 ) Regulatory and Legislative Impacts (see Note 4) (86 ) (179 ) — — (265 ) Sale of Retired Plant (see Note 3) (107 ) — — — (107 ) Impairment Charges (see Notes 4, 12 and 13) (55 ) — (93 ) (60 ) (208 ) Severance Charges (see Note 21) — — — (187 ) (187 ) Impacts of the Tax Act (see Note 24) (76 ) — 3 53 (20 ) Total $ (341 ) $ (199 ) $ (106 ) $ (225 ) $ (871 ) DUKE ENERGY CAROLINAS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 1,744 $ 1,713 $ 2,162 $ 1,776 $ 7,395 Operating income 435 451 793 347 2,026 Net income 293 301 590 219 1,403 2018 Operating revenues $ 1,763 $ 1,672 $ 2,090 $ 1,775 $ 7,300 Operating income 482 224 713 241 1,660 Net income 323 117 496 135 1,071 The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (4 ) $ (2 ) $ (2 ) $ (1 ) $ (9 ) Regulatory and Legislative Impacts (see Note 4) (19 ) (179 ) — — (198 ) Severance Charges (see Note 21) — — — (102 ) (102 ) Impacts of the Tax Act (see Note 24) — — (1 ) — (1 ) Total $ (23 ) $ (181 ) $ (3 ) $ (103 ) $ (310 ) PROGRESS ENERGY First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 2,572 $ 2,744 $ 3,242 $ 2,644 $ 11,202 Operating income 488 580 786 447 2,301 Net income 248 329 521 229 1,327 Net income attributable to Parent 249 328 521 229 1,327 2018 Operating revenues $ 2,576 $ 2,498 $ 3,045 $ 2,609 $ 10,728 Operating income 447 484 663 334 1,928 Net income 237 267 406 123 1,033 Net income attributable to Parent 235 265 404 123 1,027 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Impairment Charges (see Note 4) $ — $ — $ 25 $ 11 $ 36 Total $ — $ — $ 25 $ 11 $ 36 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (4 ) $ (3 ) $ (1 ) $ (2 ) $ (10 ) Regulatory and Legislative Impacts (see Note 4) (67 ) — — — (67 ) Impairment Charges (see Note 4) — — — (60 ) (60 ) Severance Charges (see Note 21) — — — (69 ) (69 ) Impacts of the Tax Act (see Note 24) (1 ) — (5 ) (19 ) (25 ) Total $ (72 ) $ (3 ) $ (6 ) $ (150 ) $ (231 ) DUKE ENERGY PROGRESS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 1,484 $ 1,387 $ 1,688 $ 1,398 $ 5,957 Operating income 300 259 373 236 1,168 Net income 203 169 278 155 805 2018 Operating revenues $ 1,460 $ 1,291 $ 1,582 $ 1,366 $ 5,699 Operating income 269 233 330 227 1,059 Net income 177 139 216 135 667 The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (2 ) $ (2 ) $ (1 ) $ (1 ) $ (6 ) Regulatory and Legislative Impacts (see Note 4) (67 ) — — — (67 ) Severance Charges (see Note 21) — — — (52 ) (52 ) Impacts of the Tax Act (see Note 24) — — (4 ) (15 ) (19 ) Total $ (69 ) $ (2 ) $ (5 ) $ (68 ) $ (144 ) DUKE ENERGY FLORIDA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 1,086 $ 1,353 $ 1,548 $ 1,244 $ 5,231 Operating income 188 321 413 205 1,127 Net income 96 201 289 106 692 2018 Operating revenues $ 1,115 $ 1,203 $ 1,462 $ 1,241 $ 5,021 Operating income 173 245 331 107 856 Net income 103 168 243 40 554 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Impairment Charges (see Note 4) $ — $ — $ 25 $ 11 $ 36 Total $ — $ — $ 25 $ 11 $ 36 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (2 ) $ (1 ) $ — $ (1 ) $ (4 ) Impairment Charges (see Note 4) — — — (60 ) (60 ) Severance Charges (see Note 21) — — — (17 ) (17 ) Impacts of the Tax Act (see Note 24) — — (2 ) 2 — Total $ (2 ) $ (1 ) $ (2 ) $ (76 ) $ (81 ) DUKE ENERGY OHIO First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 531 $ 433 $ 489 $ 487 $ 1,940 Operating income 104 74 108 78 364 Net income 69 47 74 48 238 2018 Operating revenues $ 524 $ 459 $ 469 $ 505 $ 1,957 Operating (loss) income (21 ) 77 139 93 288 Net (loss) income (25 ) 46 100 55 176 The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (3 ) $ (5 ) $ — $ (6 ) $ (14 ) Sale of Retired Plant (see Note 3) (107 ) — — — (107 ) Severance Charges (see Note 21) — — — (6 ) (6 ) Impacts of the Tax Act (see Note 24) — — — (2 ) (2 ) Total $ (110 ) $ (5 ) $ — $ (14 ) $ (129 ) DUKE ENERGY INDIANA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 768 $ 714 $ 807 $ 715 $ 3,004 Operating income 169 148 235 133 685 Net income 110 97 156 73 436 2018 Operating revenues $ 731 $ 738 $ 819 $ 771 $ 3,059 Operating income 168 169 173 133 643 Net income 100 98 119 76 393 The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ — $ — $ (2 ) $ — $ (2 ) Severance Charges (see Note 21) — — — (7 ) (7 ) Total $ — $ — $ (2 ) $ (7 ) $ (9 ) PIEDMONT First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 579 $ 209 $ 168 $ 425 $ 1,381 Operating income (loss) 172 6 (13 ) 139 304 Net income (loss) 122 (7 ) (18 ) 105 202 2018 Operating revenues $ 553 $ 215 $ 172 $ 435 $ 1,375 Operating income (loss) 161 5 (19 ) 79 226 Net income (loss) 110 (8 ) (21 ) 48 129 The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (6 ) $ (9 ) $ (11 ) $ (22 ) $ (48 ) Severance Charges (see Note 21) — — — (2 ) (2 ) Total $ (6 ) $ (9 ) $ (11 ) $ (24 ) $ (50 )

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Nature of Operations and Basis of Consolidation	Nature of Operations and Basis of Consolidation Duke Energy is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the FERC and other regulatory agencies listed below. Duke Energy operates in the U.S. primarily through its direct and indirect subsidiaries. Certain Duke Energy subsidiaries are also subsidiary registrants, including Duke Energy Carolinas; Progress Energy; Duke Energy Progress; Duke Energy Florida; Duke Energy Ohio; Duke Energy Indiana and Piedmont. When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its separate Subsidiary Registrants, which along with Duke Energy, are collectively referred to as the Duke Energy Registrants. The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Consolidated Financial Statements. However, none of the Subsidiary Registrants make any representation as to information related solely to Duke Energy or the Subsidiary Registrants of Duke Energy other than itself. These Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries or VIEs where the respective Duke Energy Registrants have control. See Note 18 for additional information on VIEs. These Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. See Note 9 for additional information on joint ownership. Substantially all of the Subsidiary Registrants' operations qualify for regulatory accounting. Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Progress Energy is a public utility holding company, which conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Progress Energy is subject to regulation by FERC and other regulatory agencies listed below. Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the FPSC, NRC and FERC. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers and recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky. References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the PUCO, KPSC and FERC. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the IURC and FERC. Piedmont is a regulated public utility primarily engaged in the distribution of natural gas in portions of North Carolina, South Carolina and Tennessee. Piedmont is subject to the regulatory provisions of the NCUC, PSCSC, TPUC and FERC. Certain prior year amounts have been reclassified to conform to the current year presentation.
Discontinued Operations	Discontinued Operations Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these consolidated financial statements exclude amounts related to discontinued operations for all periods presented. See Note 2 for additional information.
Noncontrolling Interest	Noncontrolling Interest Duke Energy maintains a controlling financial interest in certain less-than wholly owned non-regulated subsidiaries. As a result, Duke Energy consolidates these subsidiaries and presents the third-party investors' portion of Duke Energy's net income (loss), net assets and comprehensive income (loss) as noncontrolling interest. Noncontrolling interest is included as a component of equity on the Consolidated Balance Sheet. Several operating agreements of Duke Energy's subsidiaries with noncontrolling interest are subject to allocations of tax attributes and cash flows in accordance with contractual agreements that vary throughout the lives of the subsidiaries. Therefore, Duke Energy and the other investors' (the owners) interests in the subsidiaries are not fixed, and the subsidiaries apply the HLBV method in allocating income or loss and other comprehensive income or loss (all measured on a pretax basis) to the owners. The HLBV method measures the amounts that each owner would hypothetically claim at each balance sheet reporting date, including tax benefits realized by the owners, upon a hypothetical liquidation of the subsidiary at the net book value of its underlying assets. The change in the amount that each owner would hypothetically receive at the reporting date compared to the amount it would have received on the previous reporting date represents the amount of income or loss allocated to each owner for the reporting period. During 2019, Duke Energy received $428 million for the sale of noncontrolling interests to tax equity members subject to the HLBV method for projects totaling 718 MW in nameplate capacity. Duke Energy allocated approximately $165 million of losses to noncontrolling tax equity members utilizing the HLBV method for the year ended December 31, 2019 . Other operating agreements of Duke Energy's subsidiaries with noncontrolling interest allocate profit and loss based on their pro rata shares of the ownership interest in the respective subsidiary. Therefore, Duke Energy allocates net income or loss and other comprehensive income or loss of these subsidiaries to the owners based on their pro rata shares.
Use of Estimates	Use of Estimates In preparing financial statements that conform to GAAP, the Duke Energy Registrants must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Regulatory Accounting	Regulatory Accounting The majority of the Duke Energy Registrants’ operations are subject to price regulation for the sale of electricity and natural gas by state utility commissions or FERC. When prices are set on the basis of specific costs of the regulated operations and an effective franchise is in place such that sufficient natural gas or electric services can be sold to recover those costs, the Duke Energy Registrants apply regulatory accounting. Regulatory accounting changes the timing of the recognition of costs or revenues relative to a company that does not apply regulatory accounting. As a result, regulatory assets and regulatory liabilities are recognized on the Consolidated Balance Sheets. Regulatory assets and liabilities are amortized consistent with the treatment of the related cost in the ratemaking process. See Note 4 for further information. Regulatory accounting rules also require recognition of a disallowance (also called "impairment") loss if it becomes probable that part of the cost of a plant under construction (or a recently completed plant or an abandoned plant) will be disallowed for ratemaking purposes and a reasonable estimate of the amount of the disallowance can be made. For example, if a cost cap is set for a plant still under construction, the amount of the disallowance is a result of a judgment as to the ultimate cost of the plant. These disallowances can require judgments on allowed future rate recovery. When it becomes probable that regulated generation, transmission or distribution assets will be abandoned, the cost of the asset is removed from plant in service. The value that may be retained as a regulatory asset on the balance sheet for the abandoned property is dependent upon amounts that may be recovered through regulated rates, including any return. As such, an impairment charge could be partially or fully offset by the establishment of a regulatory asset if rate recovery is probable. The impairment charge for a disallowance of costs for regulated plants under construction, recently completed or abandoned is based on discounted cash flows.
Regulated Fuel Costs and Purchased Power	The Duke Energy Registrants utilize cost-tracking mechanisms, commonly referred to as fuel adjustment clauses or PGA clauses. These clauses allow for the recovery of fuel and fuel-related costs, portions of purchased power, natural gas costs and hedging costs through surcharges on customer rates. The difference between the costs incurred and the surcharge revenues is recorded either as an adjustment to Operating Revenues, Operating Expenses – Fuel used in electric generation or Operating Expenses – Cost of natural gas on the Consolidated Statements of Operations, with an off-setting impact on regulatory assets or liabilities
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash All highly liquid investments with maturities of three months or less at the date of acquisition are considered cash equivalents. Duke Energy, Progress Energy and Duke Energy Florida have restricted cash balances related primarily to collateral assets, escrow deposits and VIEs. See Note 18 for additional information. Restricted cash amounts are included in Other within Current Assets and Other Noncurrent Assets on the Consolidated Balance Sheets. The following table presents the components of cash, cash equivalents and restricted cash included in the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 311 $ 48 $ 17 $ 442 $ 67 $ 36 Other 222 39 39 141 39 39 Other Noncurrent Assets Other 40 39 — 8 6 — Total cash, cash equivalents and restricted cash $ 573 $ 126 $ 56 $ 591 $ 112 $ 75
Inventory	Inventory Inventory related to regulated operations is valued at historical cost. Inventory related to nonregulated operations is valued at the lower of cost or market. Inventory is charged to expense or capitalized to property, plant and equipment when issued, primarily using the average cost method. Excess or obsolete inventory is written-down to the lower of cost or net realizable value. Once inventory has been written-down, it creates a new cost basis for the inventory that is not subsequently written-up. Provisions for inventory write-offs were not material at December 31, 2019 , and 2018 , respectively. The components of inventory are presented in the tables below.
Investments in Debt and Equity Securities	Investments in Debt and Equity Securities The Duke Energy Registrants classify investments in equity securities as FV-NI and investments in debt securities as AFS. Both categories are recorded at fair value on the Consolidated Balance Sheets. Realized and unrealized gains and losses on securities classified as FV-NI are reported through net income. Unrealized gains and losses for debt securities classified as AFS are included in AOCI until realized, except OTTIs that are included in earnings immediately. At the time gains and losses for debt securities are realized, they are reported through net income. For certain investments of regulated operations, such as substantially all of the NDTF, realized and unrealized gains and losses (including any OTTIs) on debt securities are recorded as a regulatory asset or liability. The credit loss portion of debt securities of nonregulated operations are included in earnings. Investments in debt and equity securities are classified as either current or noncurrent based on management’s intent and ability to sell these securities, taking into consideration current market liquidity. See Note 16 for further information.
Goodwill and Intangible Assets	Goodwill Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont perform annual goodwill impairment tests as of August 31 each year at the reporting unit level, which is determined to be a business segment or one level below. Duke Energy, Progress Energy, Duke Energy Ohio and Piedmont update these tests between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. See Note 12 for further information. Intangible Assets Intangible assets are included in Other in Other Noncurrent Assets on the Consolidated Balance Sheets. Generally, intangible assets are amortized using an amortization method that reflects the pattern in which the economic benefits of the intangible asset are consumed or on a straight-line basis if that pattern is not readily determinable. Amortization of intangibles is reflected in Depreciation and amortization on the Consolidated Statements of Operations. Intangible assets are subject to impairment testing and if impaired, the carrying value is accordingly reduced. Emission allowances permit the holder of the allowance to emit certain gaseous byproducts of fossil fuel combustion, including SO 2 and NO X . Allowances are issued by the EPA at zero cost and may also be bought and sold via third-party transactions. Allowances allocated to or acquired by the Duke Energy Registrants are held primarily for consumption. Carrying amounts for emission allowances are based on the cost to acquire the allowances. Emission allowances are expensed to Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. RECs are used to measure compliance with renewable energy standards and are held primarily for consumption. See Note 12 for further information.
Long-Lived Asset Impairments	Long-Lived Asset Impairments The Duke Energy Registrants evaluate long-lived assets, excluding goodwill, for impairment when circumstances indicate the carrying value of those assets may not be recoverable. An impairment exists when a long-lived asset’s carrying value exceeds the estimated undiscounted cash flows expected to result from the use and eventual disposition of the asset. The estimated cash flows may be based on alternative expected outcomes that are probability weighted. If the carrying value of the long-lived asset is not recoverable based on these estimated future undiscounted cash flows, the carrying value of the asset is written-down to its then-current estimated fair value and an impairment charge is recognized. The Duke Energy Registrants assess fair value of long-lived assets using various methods, including recent comparable third-party sales, internally developed discounted cash flow analysis and analysis from outside advisors. Triggering events to reassess cash flows may include, but are not limited to, significant changes in commodity prices, the condition of an asset or management’s interest in selling the asset.
Equity Method Investment Impairments	Equity Method Investment Impairments Investments in affiliates that are not controlled by Duke Energy, but over which it has significant influence, are accounted for using the equity method. Equity method investments are assessed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable. If the decline in value is considered to be other than temporary, the investment is written down to its estimated fair value, which establishes a new cost basis in the investment. Impairment assessments use a discounted cash flow income approach and include consideration of the severity and duration of any decline in the fair value of the investments. The estimated cash flows may be based on alternative expected outcomes that are probability weighted. Key inputs that involve estimates and significant management judgment include cash flow projections, selection of a discount rate, probability weighting of potential outcomes, and whether any decline in value is considered temporary.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at the lower of depreciated historical cost net of any disallowances or fair value, if impaired. The Duke Energy Registrants capitalize all construction-related direct labor and material costs, as well as indirect construction costs such as general engineering, taxes and financing costs. See “Allowance for Funds Used During Construction and Interest Capitalized” for information on capitalized financing costs. Costs of renewals and betterments that extend the useful life of property, plant and equipment are also capitalized. The cost of repairs, replacements and major maintenance projects, which do not extend the useful life or increase the expected output of the asset, are expensed as incurred. Depreciation is generally computed over the estimated useful life of the asset using the composite straight-line method. Depreciation studies are conducted periodically to update composite rates and are approved by state utility commissions and/or the FERC when required. The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2019 2018 2017 Duke Energy 3.1 % 3.0 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.8 % Progress Energy 3.1 % 2.9 % 2.6 % Duke Energy Progress 3.1 % 2.9 % 2.6 % Duke Energy Florida 3.1 % 3.0 % 2.8 % Duke Energy Ohio 2.6 % 2.8 % 2.8 % Duke Energy Indiana 3.3 % 3.3 % 3.0 % Piedmont 2.4 % 2.5 % 2.3 % In general, when the Duke Energy Registrants retire regulated property, plant and equipment, the original cost plus the cost of retirement, less salvage value and any depreciation already recognized, is charged to accumulated depreciation. However, when it becomes probable the asset will be retired substantially in advance of its original expected useful life or is abandoned, the cost of the asset and the corresponding accumulated depreciation is recognized as a separate asset. If the asset is still in operation, the net amount is classified as Generation facilities to be retired, net on the Consolidated Balance Sheets. If the asset is no longer operating, the net amount is classified in Regulatory assets on the Consolidated Balance Sheets if deemed recoverable (see discussion of long-lived asset impairments above). The carrying value of the asset is based on historical cost if the Duke Energy Registrants are allowed to recover the remaining net book value and a return equal to at least the incremental borrowing rate. If not, an impairment is recognized to the extent the net book value of the asset exceeds the present value of future revenues discounted at the incremental borrowing rate. When the Duke Energy Registrants sell entire regulated operating units, or retire or sell nonregulated properties, the original cost and accumulated depreciation and amortization balances are removed from Property, Plant and Equipment on the Consolidated Balance Sheets. Any gain or loss is recorded in earnings, unless otherwise required by the applicable regulatory body. See Note 11 for additional information.
Nuclear Fuel	Nuclear Fuel Nuclear fuel is classified as Property, Plant and Equipment on the Consolidated Balance Sheets. Nuclear fuel in the front-end fuel processing phase is considered work in progress and not amortized until placed in service. Amortization of nuclear fuel is included within Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Amortization is recorded using the units-of-production method.
Allowance for Funds Used During Construction and Interest Capitalized	Allowance for Funds Used During Construction and Interest Capitalized For regulated operations, the debt and equity costs of financing the construction of property, plant and equipment are reflected as AFUDC and capitalized as a component of the cost of property, plant and equipment. AFUDC equity is reported on the Consolidated Statements of Operations as non-cash income in Other income and expenses, net. AFUDC debt is reported as a non-cash offset to Interest Expense. After construction is completed, the Duke Energy Registrants are permitted to recover these costs through their inclusion in rate base and the corresponding subsequent depreciation or amortization of those regulated assets. AFUDC equity, a permanent difference for income taxes, reduces the ETR when capitalized and increases the ETR when depreciated or amortized. See Note 24 for additional information. For nonregulated operations, interest is capitalized during the construction phase with an offsetting non-cash credit to Interest Expense on the Consolidated Statements of Operations.
Asset Retirement Obligations	Asset Retirement Obligations AROs are recognized for legal obligations associated with the retirement of property, plant and equipment. Substantially all AROs are related to regulated operations. When recording an ARO, the present value of the projected liability is recognized in the period in which it is incurred, if a reasonable estimate of fair value can be made. The liability is accreted over time. For operating plants, the present value of the liability is added to the cost of the associated asset and depreciated over the remaining life of the asset. For retired plants, the present value of the liability is recorded as a regulatory asset unless determined not to be probable of recovery. The present value of the initial obligation and subsequent updates are based on discounted cash flows, which include estimates regarding timing of future cash flows, selection of discount rates and cost escalation rates, among other factors. These estimates are subject to change. Depreciation expense is adjusted prospectively for any changes to the carrying amount of the associated asset. The Duke Energy Registrants receive amounts to fund the cost of the ARO for regulated operations through a combination of regulated revenues and earnings on the NDTF. As a result, amounts recovered in regulated revenues, earnings on the NDTF, accretion expense and depreciation of the associated asset are netted and deferred as a regulatory asset or liability. Obligations for nuclear decommissioning are based on site-specific cost studies. Duke Energy Carolinas and Duke Energy Progress assume prompt dismantlement of the nuclear facilities after operations are ceased. In 2019, Duke Energy Florida entered into an agreement for the accelerated decommissioning of Crystal River Unit 3. See Note 4 for more information. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida also assume that spent fuel will be stored on-site until such time that it can be transferred to a yet to be built DOE facility. Obligations for closure of ash basins are based upon discounted cash flows of estimated costs for site-specific plans, if known, or probability weightings of the potential closure methods if the closure plans are under development and multiple closure options are being considered and evaluated on a site-by-site basis. See Note 10
Revenue Recognition	Revenue Recognition Duke Energy recognizes revenue as customers obtain control of promised goods and services in an amount that reflects consideration expected in exchange for those goods or services. Generally, the delivery of electricity and natural gas results in the transfer of control to customers at the time the commodity is delivered and the amount of revenue recognized is equal to the amount billed to each customer, including estimated volumes delivered when billings have not yet occurred. See Note 19 for further information.
Derivatives and Hedging	Derivatives and Hedging Derivative and non-derivative instruments may be used in connection with commodity price and interest rate activities, including swaps, futures, forwards and options. All derivative instruments, except those that qualify for the NPNS exception, are recorded on the Consolidated Balance Sheets at fair value. Qualifying derivative instruments may be designated as either cash flow hedges or fair value hedges. Other derivative instruments (undesignated contracts) either have not been designated or do not qualify as hedges. The effective portion of the change in the fair value of cash flow hedges is recorded in AOCI. The effective portion of the change in the fair value of a fair value hedge is offset in net income by changes in the hedged item. For activity subject to regulatory accounting, gains and losses on derivative contracts are reflected as regulatory assets or liabilities and not as other comprehensive income or current period income. As a result, changes in fair value of these derivatives have no immediate earnings impact. Formal documentation, including transaction type and risk management strategy, is maintained for all contracts accounted for as a hedge. At inception and at least every three months thereafter, the hedge contract is assessed to see if it is highly effective in offsetting changes in cash flows or fair values of hedged items.
Captive Insurance Reserves	Captive Insurance Reserves Duke Energy has captive insurance subsidiaries that provide coverage, on an indemnity basis, to the Subsidiary Registrants as well as certain third parties, on a limited basis, for financial losses, primarily related to property, workers’ compensation and general liability. Liabilities include provisions for estimated losses incurred but not reported (IBNR), as well as estimated provisions for known claims. IBNR reserve estimates are primarily based upon historical loss experience, industry data and other actuarial assumptions. Reserve estimates are adjusted in future periods as actual losses differ from experience. Duke Energy, through its captive insurance entities, also has reinsurance coverage with third parties for certain losses above a per occurrence and/or aggregate retention. Receivables for reinsurance coverage are recognized when realization is deemed probable.
Unamortized Debt Premium, Discount and Expense	Unamortized Debt Premium, Discount and Expense Premiums, discounts and expenses incurred with the issuance of outstanding long-term debt are amortized over the term of the debt issue. The gain or loss on extinguishment associated with refinancing higher-cost debt obligations in the regulated operations is amortized over the remaining life of the original instrument. Amortization expense is recorded as Interest Expense in the Consolidated Statements of Operations and is reflected as Depreciation, amortization and accretion within Net cash provided by operating activities on the Consolidated Statements of Cash Flows. Premiums, discounts and expenses are presented as an adjustment to the carrying value of the debt amount and included in Long-Term Debt on the Consolidated Balance Sheets presented.
Loss Contingencies and Environmental Liabilities	Loss Contingencies and Environmental Liabilities Contingent losses are recorded when it is probable a loss has occurred and can be reasonably estimated. When a range of the probable loss exists and no amount within the range is a better estimate than any other amount, the minimum amount in the range is recorded. Unless otherwise required by GAAP, legal fees are expensed as incurred. Environmental liabilities are recorded on an undiscounted basis when environmental remediation or other liabilities become probable and can be reasonably estimated. Environmental expenditures related to past operations that do not generate current or future revenues are expensed. Environmental expenditures related to operations that generate current or future revenues are expensed or capitalized, as appropriate. Certain environmental expenditures receive regulatory accounting treatment and are recorded as regulatory assets.
Pension and Other Post-Retirement Benefit Plans	Pension and Other Post-Retirement Benefit Plans
Severance and Special Termination Benefits	Severance and Special Termination Benefits
Guarantees	Guarantees
Stock-Based Compensation	Stock-Based Compensation
Income Taxes	Income Taxes Duke Energy and its subsidiaries file a consolidated federal income tax return and other state and foreign jurisdictional returns. The Subsidiary Registrants are parties to a tax-sharing agreement with Duke Energy. Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. Deferred income taxes have been provided for temporary differences between GAAP and tax bases of assets and liabilities because the differences create taxable or tax-deductible amounts for future periods. ITCs associated with regulated operations are deferred and amortized as a reduction of income tax expense over the estimated useful lives of the related properties. Accumulated deferred income taxes are valued using the enacted tax rate expected to apply to taxable income in the periods in which the deferred tax asset or liability is expected to be settled or realized. In the event of a change in tax rates, deferred tax assets and liabilities are remeasured as of the enactment date of the new rate. To the extent that the change in the value of the deferred tax represents an obligation to customers, the impact of the remeasurement is deferred to a regulatory liability. Remaining impacts are recorded in income from continuing operations. If Duke Energy's estimate of the tax effect of reversing temporary differences is not reflective of actual outcomes, is modified to reflect new developments or interpretations of the tax law, revised to incorporate new accounting principles, or changes in the expected timing or manner of the reversal then Duke Energy's results of operations could be impacted. Tax-related interest and penalties are recorded in Interest Expense and Other Income and Expenses, net in the Consolidated Statements of Operations.
Accounting for Renewable Energy Tax Credits	Accounting for Renewable Energy Tax Credits When Duke Energy receives ITCs on wind or solar facilities, it reduces the basis of the property recorded on the Consolidated Balance Sheets by the amount of the ITC and, therefore, the ITC benefit is ultimately recognized in the statement of operations through reduced depreciation expense. Additionally, certain tax credits and government grants result in an initial tax depreciable base in excess of the book carrying value by an amount equal to one half of the ITC. Deferred tax benefits are recorded as a reduction to income tax expense in the period that the basis difference is created.
Excise Taxes	Excise Taxes Certain excise taxes levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis. Taxes for which Duke operates merely as a collection agent for the state and local government are accounted for on a net basis. Excise taxes accounted for on a gross basis within both Operating Revenues and Property and other taxes in the Consolidated Statements of Operations were as follows.
Dividend Restrictions and Unappropriated Retained Earnings	Dividend Restrictions and Unappropriated Retained Earnings Duke Energy does not have any legal, regulatory or other restrictions on paying common stock dividends to shareholders. However, as further described in Note 4
New Accounting Standard	New Accounting Standards Except as noted below, the new accounting standards adopted for 2019 , 2018 and 2017 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. Leases. In February 2016, the FASB issued revised accounting guidance for leases. The core principle of this guidance is that a lessee should recognize the assets and liabilities that arise from leases on the balance sheet. This resulted in a material impact on the presentation for the statement of financial position of the Duke Energy Registrants for the period ended December 31, 2019 , and an immaterial impact to the Duke Energy Registrants' results of operations and cash flows for the year ended December 31, 2019 . Duke Energy elected the modified retrospective method of adoption effective January 1, 2019. Under the modified retrospective method of adoption, prior year reported results are not restated. For adoption, Duke Energy elected to apply the following practical expedients: Practical Expedient Description Package of transition practical expedients (for leases commenced prior to adoption date and must be adopted as a package) Do not need to 1) reassess whether any expired or existing contracts are/or contain leases, 2) reassess the lease classification for any expired or existing leases and 3) reassess initial direct costs for any existing leases. Short-term lease expedient (elect by class of underlying asset) Elect as an accounting policy to not apply the recognition requirements to short-term leases by asset class. Lease and non-lease components (elect by class of underlying asset) Elect as an accounting policy to not separate non-lease components from lease components and instead account for each lease and associated non-lease component as a single lease component by asset class. Hindsight expedient (when determining lease term) Elect to use hindsight to determine the lease term. Existing and expired land easements not previously accounted for as leases Elect to not evaluate existing or expired easements under the new guidance and carry forward current accounting treatment. Comparative reporting requirements for initial adoption Elect to apply transition requirements at adoption date, recognize cumulative effect adjustment to retained earnings in period of adoption and not apply the new requirements to comparative periods, including disclosures. Lessor expedient (elect by class of underlying asset) Elect as an accounting policy to aggregate non-lease components with the related lease component when specified conditions are met by asset class. Account for the combined component based on its predominant characteristic (revenue or operating lease). Duke Energy evaluated the financial statement impact of adopting the standard and monitored industry implementation issues. Under agreements considered leases, where Duke Energy is the lessee, for the use of certain aircraft, space on communication towers, industrial equipment, fleet vehicles, fuel transportation (barges and railcars), land, office space and PPAs are now recognized on the balance sheet. The Duke Energy Registrants did not have a material change to the financial statements from the adoption of the new standard for contracts where it is the lessor. See Note 6 for further information. The following new accounting standard has been issued but not yet adopted by the Duke Energy Registrants as of December 31, 2019 . Credit Losses. In June 2016, the FASB issued new accounting guidance for credit losses. This guidance establishes a new impairment model applicable to certain financial assets, including trade and other receivables, net investments in leases, and debt securities classified as held-for-sale investments. The model also applies to financial guarantees. For Duke Energy, the guidance is effective for interim and annual periods beginning January 1, 2020. This guidance will be applied using a modified retrospective approach. Under the modified retrospective approach of adoption, prior year reported results are not restated and a cumulative-effect adjustment is recorded to retained earnings at January 1, 2020. Upon adoption, Duke Energy will recognize an allowance for credit losses based on management's estimate of losses expected to be incurred over the lives of certain assets or guarantees. Duke Energy expects the impacts of this standard to be driven by the reserve for credit losses on financial guarantees, trade and other receivables, and insurance receivables. Duke Energy does not intend to adopt any practical expedients. Duke Energy currently expects to record a reserve for credit losses as shown in approximate amounts in the table below: December 31, 2019 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Piedmont Total pretax impact to Retained Earnings $ 120 $ 16 $ 2 $ 1 $ 1 $ 1 In addition to the reserve for credit losses, Duke Energy expects additional disclosures on management's evaluation of credit risks inherent in financial assets and how management monitors credit quality, changes in expected credit losses, and the appropriateness of the allowance for credit losses on a forward-looking basis. Duke Energy also expects additional disclosures around credit losses for new investments in leases, loan commitments, and other financial instruments.
Earnings Per Share	Basic EPS is computed by dividing net income available to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income available to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options and equity forward sale agreements, were exercised or settled.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Current and Noncurrent Assets and Liabilities	The following table provides a description of amounts included in Other within Current Assets or Current Liabilities that exceed 5% of total Current Assets or Current Liabilities on the Duke Energy Registrants' Consolidated Balance Sheets at either December 31, 2019 , or 2018 . December 31, (in millions) Location 2019 2018 Duke Energy Taxes receivable Current Assets $ 357 $ 729 Accrued compensation Current Liabilities 862 793 Duke Energy Carolinas Accrued compensation Current Liabilities $ 271 $ 251 Other accrued liabilities Current Liabilities 147 55 Progress Energy Customer deposits Current Liabilities $ 354 $ 345 Duke Energy Florida Customer deposits Current Liabilities $ 209 $ 208 Other accrued liabilities Current Liabilities 89 85 Duke Energy Indiana Income taxes receivable Current Assets $ 44 $ 9 Customer deposits Current Liabilities 49 47
Schedule of Cash and Cash Equivalents	The following table presents the components of cash, cash equivalents and restricted cash included in the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 311 $ 48 $ 17 $ 442 $ 67 $ 36 Other 222 39 39 141 39 39 Other Noncurrent Assets Other 40 39 — 8 6 — Total cash, cash equivalents and restricted cash $ 573 $ 126 $ 56 $ 591 $ 112 $ 75
Components of Inventory	The components of inventory are presented in the tables below. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,297 $ 768 $ 1,038 $ 686 $ 351 $ 79 $ 318 $ 5 Coal 586 187 186 138 48 15 198 — Natural gas, oil and other 349 41 199 110 90 41 1 67 Total inventory $ 3,232 $ 996 $ 1,423 $ 934 $ 489 $ 135 $ 517 $ 72 December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,238 $ 731 $ 1,049 $ 734 $ 315 $ 84 $ 312 $ 2 Coal 491 175 192 106 86 14 109 — Natural gas, oil and other 355 42 218 114 103 28 1 68 Total inventory $ 3,084 $ 948 $ 1,459 $ 954 $ 504 $ 126 $ 422 $ 70
Schedule of Property, Plant and Equipment	The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2019 2018 2017 Duke Energy 3.1 % 3.0 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.8 % Progress Energy 3.1 % 2.9 % 2.6 % Duke Energy Progress 3.1 % 2.9 % 2.6 % Duke Energy Florida 3.1 % 3.0 % 2.8 % Duke Energy Ohio 2.6 % 2.8 % 2.8 % Duke Energy Indiana 3.3 % 3.3 % 3.0 % Piedmont 2.4 % 2.5 % 2.3 % The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants. December 31, 2019 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Land $ 2,091 $ 520 $ 884 $ 449 $ 435 $ 150 $ 117 $ 388 Plant – Regulated Electric generation, distribution and transmission 15-100 111,739 42,723 48,142 30,018 18,124 5,838 15,032 — Natural gas transmission and distribution 4-73 9,839 — — — — 2,892 — 6,947 Other buildings and improvements 23-90 1,810 714 401 162 239 269 278 148 Plant – Nonregulated Electric generation, distribution and transmission 5-30 5,103 — — — — — — — Other buildings and improvements 25-35 488 — — — — — — — Nuclear fuel 3,253 1,891 1,362 1,362 — — — — Equipment 3-25 2,313 546 665 452 213 319 205 128 Construction in process 6,102 1,389 2,149 1,114 1,035 504 381 531 Other 2-40 4,916 1,139 1,467 1,046 411 269 292 304 Total property, plant and equipment (a)(e) 147,654 48,922 55,070 34,603 20,457 10,241 16,305 8,446 Total accumulated depreciation – regulated (b)(c) (43,419 ) (16,525 ) (17,159 ) (11,915 ) (5,236 ) (2,843 ) (5,233 ) (1,681 ) Total accumulated depreciation – nonregulated (d)(e) (2,354 ) — — — — — — — Generation facilities to be retired, net 246 — 246 246 — — — — Total net property, plant and equipment $ 102,127 $ 32,397 $ 38,157 $ 22,934 $ 15,221 $ 7,398 $ 11,072 $ 6,765 (a) Includes finance leases of $952 million , $211 million , $443 million , $308 million , $135 million and $10 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $143 million , $17 million and $126 million , respectively, of accumulated amortization of finance leases. (b) Includes $1,807 million , $1,082 million , $725 million and $725 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of finance leases of $6 million , $13 million and $3 million at Duke Energy, Duke Energy Carolinas and Duke Energy Indiana, respectively. (d) Includes accumulated amortization of finance leases of $20 million at Duke Energy. (e) Includes gross property, plant and equipment cost of consolidated VIEs of $5,747 million and accumulated depreciation of consolidated VIEs of $1,041 million at Duke Energy. December 31, 2018 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Land $ 2,072 $ 472 $ 868 $ 445 $ 423 $ 136 $ 116 $ 448 Plant – Regulated Electric generation, distribution and transmission 15-100 100,706 38,468 42,760 26,147 16,613 5,182 14,292 — Natural gas transmission and distribution 12-80 8,808 — — — — 2,719 — 6,089 Other buildings and improvements 24-90 1,966 681 636 295 341 270 253 126 Plant – Nonregulated Electric generation, distribution and transmission 5-30 4,410 — — — — — — — Other buildings and improvements 25-35 494 — — — — — — — Nuclear fuel 3,460 1,898 1,562 1,562 — — — — Equipment 3-55 2,141 467 565 399 166 384 178 141 Construction in process 5,726 1,678 2,515 1,659 856 412 325 382 Other 3-40 4,675 1,077 1,354 952 393 257 279 300 Total property, plant and equipment (a)(d) 134,458 44,741 50,260 31,459 18,792 9,360 15,443 7,486 Total accumulated depreciation – regulated (b)(c)(d) (41,079 ) (15,496 ) (16,398 ) (11,423 ) (4,968 ) (2,717 ) (4,914 ) (1,575 ) Total accumulated depreciation – nonregulated (c)(d) (2,047 ) — — — — — — — Generation facilities to be retired, net 362 — 362 362 — — — — Total net property, plant and equipment $ 91,694 $ 29,245 $ 34,224 $ 20,398 $ 13,824 $ 6,643 $ 10,529 $ 5,911 (a) Includes finance leases of $1,237 million , $135 million , $257 million , $137 million , $120 million , $73 million and $35 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $131 million , $14 million and $117 million , respectively, of accumulated amortization of finance leases. (b) Includes $1,947 million , $1,087 million , $860 million and $860 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of finance leases of $61 million , $12 million , $20 million and $10 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $4,007 million and accumulated depreciation of consolidated VIEs of $698 million at Duke Energy.
Schedule of Excise Taxes	Excise taxes accounted for on a gross basis within both Operating Revenues and Property and other taxes in the Consolidated Statements of Operations were as follows. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy $ 421 $ 405 $ 376 Duke Energy Carolinas 39 35 36 Progress Energy 256 241 220 Duke Energy Progress 21 19 19 Duke Energy Florida 235 222 201 Duke Energy Ohio 101 105 98 Duke Energy Indiana 23 22 20 Piedmont 2 2 2
Summary of Effects of New Accounting Pronouncements	Duke Energy elected the modified retrospective method of adoption effective January 1, 2019. Under the modified retrospective method of adoption, prior year reported results are not restated. For adoption, Duke Energy elected to apply the following practical expedients: Practical Expedient Description Package of transition practical expedients (for leases commenced prior to adoption date and must be adopted as a package) Do not need to 1) reassess whether any expired or existing contracts are/or contain leases, 2) reassess the lease classification for any expired or existing leases and 3) reassess initial direct costs for any existing leases. Short-term lease expedient (elect by class of underlying asset) Elect as an accounting policy to not apply the recognition requirements to short-term leases by asset class. Lease and non-lease components (elect by class of underlying asset) Elect as an accounting policy to not separate non-lease components from lease components and instead account for each lease and associated non-lease component as a single lease component by asset class. Hindsight expedient (when determining lease term) Elect to use hindsight to determine the lease term. Existing and expired land easements not previously accounted for as leases Elect to not evaluate existing or expired easements under the new guidance and carry forward current accounting treatment. Comparative reporting requirements for initial adoption Elect to apply transition requirements at adoption date, recognize cumulative effect adjustment to retained earnings in period of adoption and not apply the new requirements to comparative periods, including disclosures. Lessor expedient (elect by class of underlying asset) Elect as an accounting policy to aggregate non-lease components with the related lease component when specified conditions are met by asset class. Account for the combined component based on its predominant characteristic (revenue or operating lease). Duke Energy currently expects to record a reserve for credit losses as shown in approximate amounts in the table below: December 31, 2019 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Piedmont Total pretax impact to Retained Earnings $ 120 $ 16 $ 2 $ 1 $ 1 $ 1

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting Information [Line Items]
Business Segment Data	Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Year Ended December 31, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 22,798 $ 1,770 $ 487 $ 25,055 $ 24 $ — $ 25,079 Intersegment Revenues 33 96 — 129 71 (200 ) — Total Revenues $ 22,831 $ 1,866 $ 487 $ 25,184 $ 95 $ (200 ) $ 25,079 Interest Expense $ 1,345 $ 117 $ 95 $ 1,557 $ 705 $ (58 ) $ 2,204 Depreciation and amortization 3,951 256 168 4,375 178 (5 ) 4,548 Equity in earnings (losses) of unconsolidated affiliates 9 114 (4 ) 119 43 — 162 Income tax expense (benefit) 785 22 (115 ) 692 (173 ) — 519 Segment income (loss) (a)(b) 3,536 432 198 4,166 (452 ) — 3,714 Add back noncontrolling interest (c) (177 ) Add back preferred stock dividend 41 Loss from discontinued operations, net of tax (7 ) Net income $ 3,571 Capital investments expenditures and acquisitions $ 8,263 $ 1,539 $ 1,423 $ 11,225 $ 221 $ — $ 11,446 Segment assets 135,561 13,921 6,020 155,502 3,148 188 158,838 (a) Electric Utilities and Infrastructure includes a $27 million reduction of a prior year impairment at Citrus County CC related to the plant's cost cap. See Note 4 for additional information. (b) Gas Utilities and Infrastructure includes an after-tax impairment charge of $19 million for the remaining investment in Constitution. See Note 13 for additional information. (c) Includes the allocation of losses to noncontrolling tax equity members. See Note 1 for additional information. Year Ended December 31, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 22,242 $ 1,783 $ 477 $ 24,502 $ 19 $ — $ 24,521 Intersegment Revenues 31 98 — 129 70 (199 ) — Total Revenues $ 22,273 $ 1,881 $ 477 $ 24,631 $ 89 $ (199 ) $ 24,521 Interest Expense $ 1,288 $ 106 $ 88 $ 1,482 $ 657 $ (45 ) $ 2,094 Depreciation and amortization 3,523 245 155 3,923 152 (1 ) 4,074 Equity in earnings (losses) of unconsolidated affiliates 5 27 (1 ) 31 52 — 83 Income tax expense (benefit) (a) 799 78 (147 ) 730 (282 ) — 448 Segment income (loss) (b)(c)(d)(e) 3,058 274 9 3,341 (694 ) — 2,647 Add back noncontrolling interest component (22 ) Loss from discontinued operations, net of tax 19 Net income $ 2,644 Capital investments expenditures and acquisitions $ 8,086 $ 1,133 $ 193 $ 9,412 $ 256 $ — $ 9,668 Segment assets 125,364 12,361 4,204 141,929 3,275 188 145,392 (a) All segments include adjustments to the December 31, 2017, estimate of the income tax effects of the Tax Act. Electric Utilities and Infrastructure includes a $24 million expense, Gas Utilities and Infrastructure includes a $1 million expense, Commercial Renewables includes a $3 million benefit and Other includes a $2 million benefit. See Note 24 for additional information. (b) Electric Utilities and Infrastructure includes after-tax regulatory and legislative impairment charges of $202 million related to rate case orders, settlements or other actions of regulators or legislative bodies and an after-tax impairment charge of $46 million related to the Citrus County CC at Duke Energy Florida. See Note 4 for additional information. (c) Gas Utilities and Infrastructure includes an after-tax impairment charge of $42 million for the investment in Constitution. See Note 13 for additional information. (d) Commercial Renewables includes an impairment charge of $91 million , net of $2 million Noncontrolling interests, related to goodwill. See Note 12 for additional information. (e) Other includes $65 million of after-tax costs to achieve the Piedmont merger, $144 million of after-tax severance charges related to a companywide initiative and an $82 million after-tax loss on the sale of Beckjord described below. For additional information, see Note 2 for the Piedmont Merger and Note 21 for severance charges. In February 2018, Duke Energy sold Beckjord, a nonregulated facility retired during 2014, and recorded a pretax loss of $106 million within (Losses) Gains on Sales of Other Assets and Other, net and $1 million within Operation, maintenance and other on Duke Energy's Consolidated Statements of Operations for the year ended December 31, 2018. The sale included the transfer of coal ash basins and other real property and indemnification from any and all potential future claims related to the property, whether arising under environmental laws or otherwise. Year Ended December 31, 2017 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,300 $ 1,743 $ 460 $ 23,503 $ 62 $ — $ 23,565 Intersegment Revenues 31 93 — 124 76 (200 ) — Total Revenues $ 21,331 $ 1,836 $ 460 $ 23,627 $ 138 $ (200 ) $ 23,565 Interest Expense $ 1,240 $ 105 $ 87 $ 1,432 $ 574 $ (20 ) $ 1,986 Depreciation and amortization 3,010 231 155 3,396 131 — 3,527 Equity in earnings (losses) of unconsolidated affiliates 5 62 (5 ) 62 57 — 119 Income tax expense (benefit) (a) 1,355 116 (628 ) 843 353 — 1,196 Segment income (loss) (b)(c)(d) 3,210 319 441 3,970 (905 ) — 3,065 Add back noncontrolling interest component 5 Loss from discontinued operations, net of tax (6 ) Net income $ 3,064 Capital investments expenditures and acquisitions $ 7,024 $ 907 $ 92 $ 8,023 $ 175 $ — $ 8,198 Segment assets 119,423 11,462 4,156 135,041 2,685 188 137,914 (a) All segments include impacts of the Tax Act. Electric Utilities and Infrastructure includes a $231 million benefit, Gas Utilities and Infrastructure includes a $26 million benefit, Commercial Renewables includes a $442 million benefit and Other includes charges of $597 million . (b) Electric Utilities and Infrastructure includes after-tax regulatory settlement charges of $98 million . (c) Commercial Renewables includes after-tax impairment charges of $74 million related to certain wind projects and the Energy Management Solutions reporting unit. See Notes 11 and 12 for additional information. (d) Other includes $64 million of after-tax costs to achieve the Piedmont merger. See Note 2 for additional information.
Schedule of Revenue, By Products and Services	Products and Services The following table summarizes revenues of the reportable segments by type. Retail Wholesale Retail Total (in millions) Electric Electric Natural Gas Other Revenues 2019 Electric Utilities and Infrastructure $ 19,745 $ 2,231 $ — $ 855 $ 22,831 Gas Utilities and Infrastructure — — 1,782 84 1,866 Commercial Renewables — 389 — 98 487 Total Reportable Segments $ 19,745 $ 2,620 $ 1,782 $ 1,037 $ 25,184 2018 Electric Utilities and Infrastructure $ 19,013 $ 2,345 $ — $ 915 $ 22,273 Gas Utilities and Infrastructure — — 1,817 64 1,881 Commercial Renewables — 375 — 102 477 Total Reportable Segments $ 19,013 $ 2,720 $ 1,817 $ 1,081 $ 24,631 2017 Electric Utilities and Infrastructure $ 18,177 $ 2,104 $ — $ 1,050 $ 21,331 Gas Utilities and Infrastructure — — 1,732 104 1,836 Commercial Renewables — 375 — 85 460 Total Reportable Segments $ 18,177 $ 2,479 $ 1,732 $ 1,239 $ 23,627
Duke Energy Ohio
Segment Reporting Information [Line Items]
Business Segment Data	Year Ended December 31, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,456 $ 484 $ 1,940 $ — $ — $ 1,940 Interest expense $ 80 $ 29 $ 109 $ — $ — $ 109 Depreciation and amortization 182 83 265 — — 265 Income tax expense (benefit) 20 21 41 (1 ) — 40 Segment income (loss)/Net income 159 85 244 (5 ) — 239 Loss from discontinued operations, net of tax (1 ) Net income $ 238 Capital expenditures $ 680 $ 272 $ 952 $ — $ — $ 952 Segment assets 6,188 3,116 9,304 34 — 9,338 Year Ended December 31, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,450 $ 506 $ 1,956 $ 1 $ — $ 1,957 Interest expense $ 67 $ 24 $ 91 $ 1 $ — $ 92 Depreciation and amortization 183 85 268 — — 268 Income tax expense (benefit) 47 24 71 (28 ) — 43 Segment income (loss)/Net income (a) 186 93 279 (103 ) — 176 Capital expenditures $ 655 $ 172 $ 827 $ — $ — $ 827 Segment assets 5,643 2,874 8,517 38 — 8,555 (a) Other includes the loss on the sale of Beckjord, see discussion above. Year Ended December 31, 2017 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,373 $ 508 $ 1,881 $ 42 $ — $ 1,923 Interest expense $ 62 $ 28 $ 90 $ 1 $ — $ 91 Depreciation and amortization 178 83 261 — — 261 Income tax expense (benefit) 40 39 79 (20 ) — 59 Segment income (loss) 138 85 223 (30 ) — 193 Loss from discontinued operations, net of tax (1 ) Net income $ 192 Capital expenditures $ 491 $ 195 $ 686 $ — $ — $ 686 Segment assets 5,066 2,758 7,824 66 (15 ) 7,875

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets of Duke Energy and Progress Energy. See separate tables below for balances by individual registrant. Duke Energy Progress Energy December 31, December 31, (in millions) 2019 2018 2019 2018 Regulatory Assets AROs – coal ash $ 4,084 $ 4,255 $ 1,843 $ 2,061 AROs – nuclear and other 739 772 668 601 Accrued pension and OPEB 2,391 2,654 897 1,074 Storm cost deferrals 1,399 1,117 1,214 953 Nuclear asset securitized balance, net 1,042 1,093 1,042 1,093 Debt fair value adjustment 1,019 1,099 — — Deferred fuel and purchased power 528 838 305 600 Deferred asset – Lee and Harris COLA 388 426 38 43 Hedge costs deferrals 356 204 129 74 Demand side management (DSM)/Energy Efficiency (EE) 343 449 241 256 Advanced metering infrastructure (AMI) 338 367 114 127 Retired generation facilities 331 402 266 324 Post-in-service carrying costs (PISCC) and deferred operating expenses 329 320 33 36 Vacation accrual 214 213 41 41 Derivatives – natural gas supply contracts 117 141 — — Nuclear deferral 107 133 40 46 Manufactured gas plant (MGP) 102 99 — — Deferred pipeline integrity costs 79 65 — — NCEMPA deferrals 72 50 72 50 East Bend deferrals 44 47 — — Transmission expansion obligation 36 39 — — Amounts due from customers 36 24 — — Grid modernization 28 31 — — Other 896 784 349 322 Total regulatory assets 15,018 15,622 7,292 7,701 Less: current portion 1,796 2,005 946 1,137 Total noncurrent regulatory assets $ 13,222 $ 13,617 $ 6,346 $ 6,564 Regulatory Liabilities Net regulatory liability related to income taxes $ 7,872 $ 8,058 $ 2,595 $ 2,710 Costs of removal 5,756 5,421 2,561 2,135 AROs – nuclear and other 1,100 538 — — Accrued pension and OPEB 176 301 — 149 Amounts to be refunded to customers 34 34 — — Deferred fuel and purchased power 1 16 1 16 Other 1,109 1,064 398 319 Total regulatory liabilities 16,048 15,432 5,555 5,329 Less: current portion 784 598 330 280 Total noncurrent regulatory liabilities $ 15,264 $ 14,834 $ 5,225 $ 5,049
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets of Duke Energy and Progress Energy. See separate tables below for balances by individual registrant. Duke Energy Progress Energy December 31, December 31, (in millions) 2019 2018 2019 2018 Regulatory Assets AROs – coal ash $ 4,084 $ 4,255 $ 1,843 $ 2,061 AROs – nuclear and other 739 772 668 601 Accrued pension and OPEB 2,391 2,654 897 1,074 Storm cost deferrals 1,399 1,117 1,214 953 Nuclear asset securitized balance, net 1,042 1,093 1,042 1,093 Debt fair value adjustment 1,019 1,099 — — Deferred fuel and purchased power 528 838 305 600 Deferred asset – Lee and Harris COLA 388 426 38 43 Hedge costs deferrals 356 204 129 74 Demand side management (DSM)/Energy Efficiency (EE) 343 449 241 256 Advanced metering infrastructure (AMI) 338 367 114 127 Retired generation facilities 331 402 266 324 Post-in-service carrying costs (PISCC) and deferred operating expenses 329 320 33 36 Vacation accrual 214 213 41 41 Derivatives – natural gas supply contracts 117 141 — — Nuclear deferral 107 133 40 46 Manufactured gas plant (MGP) 102 99 — — Deferred pipeline integrity costs 79 65 — — NCEMPA deferrals 72 50 72 50 East Bend deferrals 44 47 — — Transmission expansion obligation 36 39 — — Amounts due from customers 36 24 — — Grid modernization 28 31 — — Other 896 784 349 322 Total regulatory assets 15,018 15,622 7,292 7,701 Less: current portion 1,796 2,005 946 1,137 Total noncurrent regulatory assets $ 13,222 $ 13,617 $ 6,346 $ 6,564 Regulatory Liabilities Net regulatory liability related to income taxes $ 7,872 $ 8,058 $ 2,595 $ 2,710 Costs of removal 5,756 5,421 2,561 2,135 AROs – nuclear and other 1,100 538 — — Accrued pension and OPEB 176 301 — 149 Amounts to be refunded to customers 34 34 — — Deferred fuel and purchased power 1 16 1 16 Other 1,109 1,064 398 319 Total regulatory liabilities 16,048 15,432 5,555 5,329 Less: current portion 784 598 330 280 Total noncurrent regulatory liabilities $ 15,264 $ 14,834 $ 5,225 $ 5,049
Schedule of Potential Plant Retirements	The table below contains the net carrying value of generating facilities planned for retirement or included in recent IRPs as evaluated for potential retirement. Dollar amounts in the table below are included in Net property, plant and equipment on the Consolidated Balance Sheets as of December 31, 2019 , and exclude capitalized asset retirement costs. Remaining Net Capacity Book Value (in MW) (in millions) Duke Energy Carolinas Allen Steam Station Units 1-3 (a) 585 $ 152 Duke Energy Indiana Gallagher Units 2 and 4 (b) 280 114 Gibson Units 1-5 (c) 3,132 1,697 Cayuga Units 1-2 (c) 1,005 974 Total Duke Energy $ 5,002 $ 2,937 (a) Duke Energy Carolinas will retire Allen Steam Station Units 1 through 3 by December 31, 2024, as part of the resolution of a lawsuit involving alleged New Source Review violations. (b) Duke Energy Indiana committed to either retire or stop burning coal at Gallagher Units 2 and 4 by December 31, 2022, as part of the 2016 settlement of Edwardsport IGCC matters. (c) On July 1, 2019, Duke Energy Indiana filed its 2018 IRP with the IURC. The 2018 IRP included scenarios evaluating the potential retirement of coal-fired generating units at Gibson and Cayuga. The rate case filed July 2, 2019, includes proposed depreciation rates reflecting retirement dates from 2026 to 2038.
Progress Energy
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets of Duke Energy and Progress Energy. See separate tables below for balances by individual registrant. Duke Energy Progress Energy December 31, December 31, (in millions) 2019 2018 2019 2018 Regulatory Assets AROs – coal ash $ 4,084 $ 4,255 $ 1,843 $ 2,061 AROs – nuclear and other 739 772 668 601 Accrued pension and OPEB 2,391 2,654 897 1,074 Storm cost deferrals 1,399 1,117 1,214 953 Nuclear asset securitized balance, net 1,042 1,093 1,042 1,093 Debt fair value adjustment 1,019 1,099 — — Deferred fuel and purchased power 528 838 305 600 Deferred asset – Lee and Harris COLA 388 426 38 43 Hedge costs deferrals 356 204 129 74 Demand side management (DSM)/Energy Efficiency (EE) 343 449 241 256 Advanced metering infrastructure (AMI) 338 367 114 127 Retired generation facilities 331 402 266 324 Post-in-service carrying costs (PISCC) and deferred operating expenses 329 320 33 36 Vacation accrual 214 213 41 41 Derivatives – natural gas supply contracts 117 141 — — Nuclear deferral 107 133 40 46 Manufactured gas plant (MGP) 102 99 — — Deferred pipeline integrity costs 79 65 — — NCEMPA deferrals 72 50 72 50 East Bend deferrals 44 47 — — Transmission expansion obligation 36 39 — — Amounts due from customers 36 24 — — Grid modernization 28 31 — — Other 896 784 349 322 Total regulatory assets 15,018 15,622 7,292 7,701 Less: current portion 1,796 2,005 946 1,137 Total noncurrent regulatory assets $ 13,222 $ 13,617 $ 6,346 $ 6,564 Regulatory Liabilities Net regulatory liability related to income taxes $ 7,872 $ 8,058 $ 2,595 $ 2,710 Costs of removal 5,756 5,421 2,561 2,135 AROs – nuclear and other 1,100 538 — — Accrued pension and OPEB 176 301 — 149 Amounts to be refunded to customers 34 34 — — Deferred fuel and purchased power 1 16 1 16 Other 1,109 1,064 398 319 Total regulatory liabilities 16,048 15,432 5,555 5,329 Less: current portion 784 598 330 280 Total noncurrent regulatory liabilities $ 15,264 $ 14,834 $ 5,225 $ 5,049
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets of Duke Energy and Progress Energy. See separate tables below for balances by individual registrant. Duke Energy Progress Energy December 31, December 31, (in millions) 2019 2018 2019 2018 Regulatory Assets AROs – coal ash $ 4,084 $ 4,255 $ 1,843 $ 2,061 AROs – nuclear and other 739 772 668 601 Accrued pension and OPEB 2,391 2,654 897 1,074 Storm cost deferrals 1,399 1,117 1,214 953 Nuclear asset securitized balance, net 1,042 1,093 1,042 1,093 Debt fair value adjustment 1,019 1,099 — — Deferred fuel and purchased power 528 838 305 600 Deferred asset – Lee and Harris COLA 388 426 38 43 Hedge costs deferrals 356 204 129 74 Demand side management (DSM)/Energy Efficiency (EE) 343 449 241 256 Advanced metering infrastructure (AMI) 338 367 114 127 Retired generation facilities 331 402 266 324 Post-in-service carrying costs (PISCC) and deferred operating expenses 329 320 33 36 Vacation accrual 214 213 41 41 Derivatives – natural gas supply contracts 117 141 — — Nuclear deferral 107 133 40 46 Manufactured gas plant (MGP) 102 99 — — Deferred pipeline integrity costs 79 65 — — NCEMPA deferrals 72 50 72 50 East Bend deferrals 44 47 — — Transmission expansion obligation 36 39 — — Amounts due from customers 36 24 — — Grid modernization 28 31 — — Other 896 784 349 322 Total regulatory assets 15,018 15,622 7,292 7,701 Less: current portion 1,796 2,005 946 1,137 Total noncurrent regulatory assets $ 13,222 $ 13,617 $ 6,346 $ 6,564 Regulatory Liabilities Net regulatory liability related to income taxes $ 7,872 $ 8,058 $ 2,595 $ 2,710 Costs of removal 5,756 5,421 2,561 2,135 AROs – nuclear and other 1,100 538 — — Accrued pension and OPEB 176 301 — 149 Amounts to be refunded to customers 34 34 — — Deferred fuel and purchased power 1 16 1 16 Other 1,109 1,064 398 319 Total regulatory liabilities 16,048 15,432 5,555 5,329 Less: current portion 784 598 330 280 Total noncurrent regulatory liabilities $ 15,264 $ 14,834 $ 5,225 $ 5,049
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on Duke Energy Carolinas' Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 1,696 $ 1,725 (i) (b) Accrued pension and OPEB 477 581 (j) Storm cost deferrals 178 160 Yes (b) Deferred fuel and purchased power 222 196 (f) 2021 Deferred asset – Lee COLA 350 383 (b) Hedge costs deferrals (c) 198 101 Yes 2041 DSM/EE 100 169 (h) (h) AMI 166 176 Yes (b) Retired generation facilities (c) 16 21 Yes 2023 PISCC (c) 33 34 Yes (b) Vacation accrual 80 78 (e) 2020 Nuclear deferral 67 87 2021 Other 327 266 (b) Total regulatory assets 3,910 3,977 Less: current portion 550 520 Total noncurrent regulatory assets $ 3,360 $ 3,457 Regulatory Liabilities (a) Net regulatory liability related to income taxes (d) $ 3,060 $ 3,082 (b) Costs of removal (c) 1,936 1,968 Yes (g) AROs – nuclear and other 1,100 538 (b) Accrued pension and OPEB 39 38 (j) Other 543 572 (b) Total regulatory liabilities 6,678 6,198 Less: current portion 255 199 Total noncurrent regulatory liabilities $ 6,423 $ 5,999 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Includes regulatory liabilities related to the change in the federal tax rate as a result of the Tax Act and the change in the North Carolina tax rate, both discussed in Note 24 . (e) Earns a return on outstanding balance in North Carolina. (f) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina. (g) Recovered over the life of the associated assets. (h) Includes incentives on DSM/EE investments and is recovered through an annual rider mechanism. (i) Earns a debt and equity return on coal ash expenditures for North Carolina and South Carolina retail customers as permitted by various regulatory orders. (j) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on Duke Energy Carolinas' Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 1,696 $ 1,725 (i) (b) Accrued pension and OPEB 477 581 (j) Storm cost deferrals 178 160 Yes (b) Deferred fuel and purchased power 222 196 (f) 2021 Deferred asset – Lee COLA 350 383 (b) Hedge costs deferrals (c) 198 101 Yes 2041 DSM/EE 100 169 (h) (h) AMI 166 176 Yes (b) Retired generation facilities (c) 16 21 Yes 2023 PISCC (c) 33 34 Yes (b) Vacation accrual 80 78 (e) 2020 Nuclear deferral 67 87 2021 Other 327 266 (b) Total regulatory assets 3,910 3,977 Less: current portion 550 520 Total noncurrent regulatory assets $ 3,360 $ 3,457 Regulatory Liabilities (a) Net regulatory liability related to income taxes (d) $ 3,060 $ 3,082 (b) Costs of removal (c) 1,936 1,968 Yes (g) AROs – nuclear and other 1,100 538 (b) Accrued pension and OPEB 39 38 (j) Other 543 572 (b) Total regulatory liabilities 6,678 6,198 Less: current portion 255 199 Total noncurrent regulatory liabilities $ 6,423 $ 5,999 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Includes regulatory liabilities related to the change in the federal tax rate as a result of the Tax Act and the change in the North Carolina tax rate, both discussed in Note 24 . (e) Earns a return on outstanding balance in North Carolina. (f) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina. (g) Recovered over the life of the associated assets. (h) Includes incentives on DSM/EE investments and is recovered through an annual rider mechanism. (i) Earns a debt and equity return on coal ash expenditures for North Carolina and South Carolina retail customers as permitted by various regulatory orders. (j) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Duke Energy Progress
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on Duke Energy Progress' Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 1,834 $ 2,051 (h) (b) AROs – nuclear and other 509 429 (c) Accrued pension and OPEB 423 542 (k) Storm cost deferrals (d) 801 571 Yes (b) Deferred fuel and purchased power 266 397 (f) 2021 Deferred asset – Harris COLA 38 43 Hedge costs deferrals 85 54 (b) DSM/EE (e) 216 235 (i) (i) AMI 61 67 (b) Retired generation facilities 83 105 Yes (b) PISCC and deferred operating expenses 33 36 Yes 2054 Vacation accrual 41 41 2020 Nuclear deferral 40 46 2021 NCEMPA deferrals 72 50 (g) 2042 Other 176 147 (b) Total regulatory assets 4,678 4,814 Less: current portion 526 703 Total noncurrent regulatory assets $ 4,152 $ 4,111 Regulatory Liabilities (a) Net regulatory liability related to income taxes (l) $ 1,802 $ 1,863 (b) Costs of removal 2,294 1,878 Yes (j) Accrued pension and OPEB — 93 (k) Other 372 299 (b) Total regulatory liabilities 4,468 4,133 Less: current portion 236 178 Total noncurrent regulatory liabilities $ 4,232 $ 3,955 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Recovery period for costs related to nuclear facilities runs through the decommissioning period of each unit. (d) South Carolina storm costs are included in rate base. (e) Included in rate base. (f) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina. (g) South Carolina retail allocated costs are earning a return. (h) Earns a debt and equity return on coal ash expenditures for North Carolina and South Carolina retail customers as permitted by various regulatory orders. (i) Includes incentives on DSM/EE investments and is recovered through an annual rider mechanism. (j) Recovered over the life of the associated assets. (k) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail. (l) Includes regulatory liabilities related to the change in the federal tax rate as a result of the Tax Act and the change in the North Carolina tax rate, both discussed in Note 23.
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on Duke Energy Progress' Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 1,834 $ 2,051 (h) (b) AROs – nuclear and other 509 429 (c) Accrued pension and OPEB 423 542 (k) Storm cost deferrals (d) 801 571 Yes (b) Deferred fuel and purchased power 266 397 (f) 2021 Deferred asset – Harris COLA 38 43 Hedge costs deferrals 85 54 (b) DSM/EE (e) 216 235 (i) (i) AMI 61 67 (b) Retired generation facilities 83 105 Yes (b) PISCC and deferred operating expenses 33 36 Yes 2054 Vacation accrual 41 41 2020 Nuclear deferral 40 46 2021 NCEMPA deferrals 72 50 (g) 2042 Other 176 147 (b) Total regulatory assets 4,678 4,814 Less: current portion 526 703 Total noncurrent regulatory assets $ 4,152 $ 4,111 Regulatory Liabilities (a) Net regulatory liability related to income taxes (l) $ 1,802 $ 1,863 (b) Costs of removal 2,294 1,878 Yes (j) Accrued pension and OPEB — 93 (k) Other 372 299 (b) Total regulatory liabilities 4,468 4,133 Less: current portion 236 178 Total noncurrent regulatory liabilities $ 4,232 $ 3,955 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Recovery period for costs related to nuclear facilities runs through the decommissioning period of each unit. (d) South Carolina storm costs are included in rate base. (e) Included in rate base. (f) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina. (g) South Carolina retail allocated costs are earning a return. (h) Earns a debt and equity return on coal ash expenditures for North Carolina and South Carolina retail customers as permitted by various regulatory orders. (i) Includes incentives on DSM/EE investments and is recovered through an annual rider mechanism. (j) Recovered over the life of the associated assets. (k) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail. (l) Includes regulatory liabilities related to the change in the federal tax rate as a result of the Tax Act and the change in the North Carolina tax rate, both discussed in Note 23.
Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on Duke Energy Florida's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash (c) $ 9 $ 10 (b) AROs – nuclear and other (c) 159 172 (b) Accrued pension and OPEB (c) 474 532 Yes (g) Storm cost deferrals (c) 413 382 (e) 2021 Nuclear asset securitized balance, net 1,042 1,093 2036 Deferred fuel and purchased power 39 203 (f) 2021 Hedge costs deferrals 44 20 2038 DSM/EE (c) 25 21 Yes 2024 AMI (c) 53 60 Yes 2032 Retired generation facilities (c) 183 219 Yes (b) Other 172 176 (d) (b) Total regulatory assets 2,613 2,888 Less: current portion 419 434 Total noncurrent regulatory assets $ 2,194 $ 2,454 Regulatory Liabilities (a) Net regulatory liability related to income taxes (c) $ 793 $ 847 (b) Costs of removal (c) 267 257 (d) (b) Accrued pension and OPEB — 56 Yes (g) Deferred fuel and purchased power (c) 1 16 (f) 2021 Other 26 20 (d) (b) Total regulatory liabilities 1,087 1,196 Less: current portion 94 102 Total noncurrent regulatory liabilities $ 993 $ 1,094 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Certain costs earn/pay a return. (e) Earns a debt return/interest once collections begin. (f) Earns commercial paper rate. (g) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on Duke Energy Florida's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash (c) $ 9 $ 10 (b) AROs – nuclear and other (c) 159 172 (b) Accrued pension and OPEB (c) 474 532 Yes (g) Storm cost deferrals (c) 413 382 (e) 2021 Nuclear asset securitized balance, net 1,042 1,093 2036 Deferred fuel and purchased power 39 203 (f) 2021 Hedge costs deferrals 44 20 2038 DSM/EE (c) 25 21 Yes 2024 AMI (c) 53 60 Yes 2032 Retired generation facilities (c) 183 219 Yes (b) Other 172 176 (d) (b) Total regulatory assets 2,613 2,888 Less: current portion 419 434 Total noncurrent regulatory assets $ 2,194 $ 2,454 Regulatory Liabilities (a) Net regulatory liability related to income taxes (c) $ 793 $ 847 (b) Costs of removal (c) 267 257 (d) (b) Accrued pension and OPEB — 56 Yes (g) Deferred fuel and purchased power (c) 1 16 (f) 2021 Other 26 20 (d) (b) Total regulatory liabilities 1,087 1,196 Less: current portion 94 102 Total noncurrent regulatory liabilities $ 993 $ 1,094 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Certain costs earn/pay a return. (e) Earns a debt return/interest once collections begin. (f) Earns commercial paper rate. (g) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Duke Energy Ohio
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on Duke Energy Ohio's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 16 $ 20 Yes (b) Accrued pension and OPEB 155 146 (g) Storm cost deferrals 7 4 2023 Deferred fuel and purchased power 1 2 2020 Hedge costs deferrals 6 5 (b) DSM/EE 2 10 (f) (e) AMI 40 46 (b) PISCC and deferred operating expenses (c) 17 17 Yes 2083 Vacation accrual 5 5 2020 MGP 102 99 (b) Deferred pipeline integrity costs 17 14 Yes (b) East Bend deferrals 44 47 Yes (b) Transmission expansion obligation 40 43 (e) Grid modernization 28 31 Yes (b) (c) Other 118 75 (b) Total regulatory assets 598 564 Less: current portion 49 33 Total noncurrent regulatory assets $ 549 $ 531 Regulatory Liabilities (a) Net regulatory liability related to income taxes $ 654 $ 678 (b) Costs of removal 86 126 (d) Accrued pension and OPEB 16 18 (g) Other 71 75 (b) Total regulatory liabilities 827 897 Less: current portion 64 57 Total noncurrent regulatory liabilities $ 763 $ 840 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Recovery over the life of the associated assets. (e) Recovered via a rider mechanism. (f) Includes incentives on DSM/EE investments. (g) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on Duke Energy Ohio's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 16 $ 20 Yes (b) Accrued pension and OPEB 155 146 (g) Storm cost deferrals 7 4 2023 Deferred fuel and purchased power 1 2 2020 Hedge costs deferrals 6 5 (b) DSM/EE 2 10 (f) (e) AMI 40 46 (b) PISCC and deferred operating expenses (c) 17 17 Yes 2083 Vacation accrual 5 5 2020 MGP 102 99 (b) Deferred pipeline integrity costs 17 14 Yes (b) East Bend deferrals 44 47 Yes (b) Transmission expansion obligation 40 43 (e) Grid modernization 28 31 Yes (b) (c) Other 118 75 (b) Total regulatory assets 598 564 Less: current portion 49 33 Total noncurrent regulatory assets $ 549 $ 531 Regulatory Liabilities (a) Net regulatory liability related to income taxes $ 654 $ 678 (b) Costs of removal 86 126 (d) Accrued pension and OPEB 16 18 (g) Other 71 75 (b) Total regulatory liabilities 827 897 Less: current portion 64 57 Total noncurrent regulatory liabilities $ 763 $ 840 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Recovery over the life of the associated assets. (e) Recovered via a rider mechanism. (f) Includes incentives on DSM/EE investments. (g) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Schedule of MISO Exit Fee Obligations	The following table provides a reconciliation of the beginning and ending balance of Duke Energy Ohio’s recorded liability for its exit obligation and share of MTEP costs recorded in Other within Current Liabilities and Other Noncurrent Liabilities on the Consolidated Balance Sheets. The retail portions of MTEP costs billed by MISO are recovered by Duke Energy Ohio through a non-bypassable rider. As of December 31, 2019, and 2018, $40 million and $43 million , respectively, are recorded in Regulatory assets on Duke Energy Ohio's Consolidated Balance Sheets. Provisions/ Cash (in millions) December 31, 2018 Adjustments Reductions December 31, 2019 Duke Energy Ohio $ 58 $ — $ (4 ) $ 54
Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on Duke Energy Indiana's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 529 $ 450 (b) Accrued pension and OPEB 243 222 (f) Deferred fuel and purchased power — 40 2020 Hedge costs deferrals 23 24 (b) DSM/EE — 14 (e) (e) AMI (c) 18 18 Yes (b) Retired generation facilities (c) 49 57 Yes 2026 PISCC and deferred operating expenses (c) 246 233 Yes (b) Vacation accrual 12 11 2020 Other 52 88 (b) Total regulatory assets 1,172 1,157 Less: current portion 90 175 Total noncurrent regulatory assets $ 1,082 $ 982 Regulatory Liabilities (a) Net regulatory liability related to income taxes $ 1,008 $ 1,009 (b) Costs of removal 599 628 (d) Accrued pension and OPEB 90 67 (f) Amounts to be refunded to customers — 1 2020 Other 43 42 (b) Total regulatory liabilities 1,740 1,747 Less: current portion 55 25 Total noncurrent regulatory liabilities $ 1,685 $ 1,722 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Refunded over the life of the associated assets. (e) Includes incentives on DSM/EE investments and is recovered through a tracker mechanism over a two-year period. (f) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on Duke Energy Indiana's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – coal ash $ 529 $ 450 (b) Accrued pension and OPEB 243 222 (f) Deferred fuel and purchased power — 40 2020 Hedge costs deferrals 23 24 (b) DSM/EE — 14 (e) (e) AMI (c) 18 18 Yes (b) Retired generation facilities (c) 49 57 Yes 2026 PISCC and deferred operating expenses (c) 246 233 Yes (b) Vacation accrual 12 11 2020 Other 52 88 (b) Total regulatory assets 1,172 1,157 Less: current portion 90 175 Total noncurrent regulatory assets $ 1,082 $ 982 Regulatory Liabilities (a) Net regulatory liability related to income taxes $ 1,008 $ 1,009 (b) Costs of removal 599 628 (d) Accrued pension and OPEB 90 67 (f) Amounts to be refunded to customers — 1 2020 Other 43 42 (b) Total regulatory liabilities 1,740 1,747 Less: current portion 55 25 Total noncurrent regulatory liabilities $ 1,685 $ 1,722 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Refunded over the life of the associated assets. (e) Includes incentives on DSM/EE investments and is recovered through a tracker mechanism over a two-year period. (f) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Piedmont
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	The following tables present the regulatory assets and liabilities recorded on Piedmont's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – nuclear and other 16 19 (d) Accrued pension and OPEB (c) 90 99 Yes (f) Vacation accrual 12 12 Derivatives – natural gas supply contracts (e) 117 141 Deferred pipeline integrity costs (c) 62 51 Yes (b) Amounts due from customers 36 24 Yes (b) Other 30 11 (b) Total regulatory assets 363 357 Less: current portion 73 54 Total noncurrent regulatory assets $ 290 $ 303 Regulatory Liabilities (a) Net regulatory liability related to income taxes $ 555 $ 579 (b) Costs of removal 574 564 (d) Accrued pension and OPEB (c) 3 1 Yes (f) Amounts to be refunded to customers 34 33 Yes (b) Other 46 41 (b) Total regulatory liabilities 1,212 1,218 Less: current portion 81 37 Total noncurrent regulatory liabilities $ 1,131 $ 1,181 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Recovery over the life of the associated assets. (e) Balance will fluctuate with changes in the market. Current contracts extend into 2031. (f) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.
Schedule Of Regulatory Liabilities	The following tables present the regulatory assets and liabilities recorded on Piedmont's Consolidated Balance Sheets. December 31, Earns/Pays Recovery/Refund (in millions) 2019 2018 a Return Period Ends Regulatory Assets (a) AROs – nuclear and other 16 19 (d) Accrued pension and OPEB (c) 90 99 Yes (f) Vacation accrual 12 12 Derivatives – natural gas supply contracts (e) 117 141 Deferred pipeline integrity costs (c) 62 51 Yes (b) Amounts due from customers 36 24 Yes (b) Other 30 11 (b) Total regulatory assets 363 357 Less: current portion 73 54 Total noncurrent regulatory assets $ 290 $ 303 Regulatory Liabilities (a) Net regulatory liability related to income taxes $ 555 $ 579 (b) Costs of removal 574 564 (d) Accrued pension and OPEB (c) 3 1 Yes (f) Amounts to be refunded to customers 34 33 Yes (b) Other 46 41 (b) Total regulatory liabilities 1,212 1,218 Less: current portion 81 37 Total noncurrent regulatory liabilities $ 1,131 $ 1,181 (a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted. (b) The expected recovery or refund period varies or has not been determined. (c) Included in rate base. (d) Recovery over the life of the associated assets. (e) Balance will fluctuate with changes in the market. Current contracts extend into 2031. (f) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 23 for additional detail.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Legal Reserves	The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Accounts payable within Current Liabilities and Other within Other Noncurrent Liabilities on the Consolidated Balance Sheets. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at December 31, 2016 $ 98 $ 10 $ 18 $ 3 $ 14 $ 59 $ 10 $ 1 Provisions/adjustments 8 3 3 2 2 3 (4 ) 1 Cash reductions (25 ) (3 ) (6 ) (2 ) (4 ) (15 ) (1 ) — Balance at December 31, 2017 81 10 15 3 12 47 5 2 Provisions/adjustments 26 3 2 3 (2 ) 21 1 1 Cash reductions (30 ) (2 ) (6 ) (2 ) (4 ) (20 ) (1 ) (1 ) Balance at December 31, 2018 77 11 11 4 6 48 5 2 Provisions/adjustments 33 6 9 2 5 11 — 7 Cash reductions (52 ) (6 ) (4 ) (2 ) (2 ) (40 ) (1 ) (1 ) Balance at December 31, 2019 $ 58 $ 11 $ 16 $ 4 $ 9 $ 19 $ 4 $ 8 The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos-related reserves. Reserves are classified on the Consolidated Balance Sheets in Other within Other Noncurrent Liabilities and Other within Current Liabilities. The reasonably possible range of loss in excess of recorded reserves is not material, other than as described above. December 31, (in millions) 2019 2018 Reserves for Legal Matters Duke Energy $ 62 $ 65 Duke Energy Carolinas 2 9 Progress Energy 55 54 Duke Energy Progress 12 12 Duke Energy Florida 22 24 Piedmont 1 1
Schedule of Additional Possible Losses in Excess of Recorded Environmental Reserves	Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 59 Duke Energy Carolinas 11 Duke Energy Ohio 42 Piedmont 2
Schedule of Purchase Power Obligations	The following table presents executory purchased power contracts with terms exceeding one year, excluding contracts classified as leases. Minimum Purchase Amount at December 31, 2019 Contract (in millions) Expiration 2020 2021 2022 2023 2024 Thereafter Total Duke Energy Progress (a) 2021-2032 $ 46 $ 66 $ 63 $ 55 $ 56 $ 123 $ 409 Duke Energy Florida (b) 2021-2025 374 356 354 374 262 91 1,811 Duke Energy Ohio (c)(d) 2021-2022 132 107 32 — — — 271 (a) Contracts represent either 100% of net plant output or vary. (b) Contracts represent between 81% and 100% of net plant output. (c) Contracts represent between 1% and 9% of net plant output. (d) Excludes PPA with OVEC. See Note 18 for additional information.
Schedule of Natural Gas Supply Contract Commitments	The following table presents future unconditional purchase obligations under natural gas supply and capacity contracts as of December 31, 2019 . (in millions) Duke Energy Duke Energy Ohio Piedmont 2020 $ 297 $ 39 $ 258 2021 280 33 247 2022 225 14 211 2023 129 3 126 2024 118 — 118 Thereafter 714 — 714 Total $ 1,763 $ 89 $ 1,674

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Balance Sheet Amounts Recorded for Operating and Finance Leases	Adoption of the new standard resulted in the recording of ROU assets and operating lease liabilities as follows: As of January 1, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont ROU assets $ 1,750 $ 153 $ 863 $ 407 $ 456 $ 23 $ 61 $ 26 Operating lease liabilities – current 205 28 96 35 61 1 4 4 Operating lease liabilities – noncurrent 1,504 127 766 371 395 22 58 25 The following tables contain additional information related to leases. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Classification Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Assets Operating Operating lease ROU assets, net $ 1,658 $ 123 $ 788 $ 387 $ 401 $ 21 $ 57 $ 24 Finance Net property, plant and equipment 926 198 443 308 135 — 7 — Total lease assets $ 2,584 $ 321 $ 1,231 $ 695 $ 536 $ 21 $ 64 $ 24 Liabilities Current Operating Other current liabilities $ 208 $ 27 $ 95 $ 37 $ 58 $ 1 $ 3 $ 4 Finance Current maturities of long-term debt 119 7 24 6 18 — — — Noncurrent Operating Operating lease liabilities 1,432 102 697 354 343 21 55 23 Finance Long-Term Debt 850 172 381 301 80 — 10 — Total lease liabilities $ 2,609 $ 308 $ 1,197 $ 698 $ 499 $ 22 $ 68 $ 27
Lease Costs and Cash Flows Information	Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Cash paid for amounts included in the measurement of lease liabilities (a) Operating cash flows from operating leases $ 285 $ 34 $ 131 $ 53 $ 78 $ 2 $ 7 $ 7 Operating cash flows from finance leases 61 15 42 33 9 — 1 — Financing cash flows from finance leases 111 6 21 5 16 1 — — Lease assets obtained in exchange for new lease liabilities (non-cash) Operating (b) $ 194 $ 44 $ 30 $ 30 $ — $ — $ — $ 1 Finance 251 76 175 175 — — — — (a) No amounts were classified as investing cash flows from operating leases for the year ended December 31, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. The following table presents the components of lease expense. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Operating lease expense (a) $ 292 $ 47 $ 161 $ 69 $ 92 $ 11 $ 20 $ 5 Short-term lease expense (a) 16 5 9 4 5 1 2 — Variable lease expense (a) 47 22 22 16 6 — 1 1 Finance lease expense Amortization of leased assets (b) 111 6 21 5 16 1 — — Interest on lease liabilities (c) 61 15 42 33 9 — 1 — Total finance lease expense 172 21 63 38 25 1 1 — Total lease expense $ 527 $ 95 $ 255 $ 127 $ 128 $ 13 $ 24 $ 6 (a) Included in Operations, maintenance and other or, for barges and railcars, Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. (b) Included in Depreciation and amortization on the Consolidated Statements of Operations. (c) Included in Interest Expense on the Consolidated Statements of Operations.
Schedule of Rent Expense	The following table presents rental expense for operating leases, as reported under the former lease standard. These amounts are included in Operation, maintenance and other and Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Years Ended December 31, (in millions) 2018 2017 Duke Energy $ 268 $ 241 Duke Energy Carolinas 49 44 Progress Energy 143 130 Duke Energy Progress 75 75 Duke Energy Florida 68 55 Duke Energy Ohio 13 15 Duke Energy Indiana 21 23 Piedmont 11 7
Operating Lease Maturities	The following table presents operating lease maturities and a reconciliation of the undiscounted cash flows to operating lease liabilities. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 268 $ 31 $ 123 $ 51 $ 72 $ 2 $ 5 $ 5 2021 216 19 99 44 55 2 4 5 2022 201 19 95 40 55 2 4 5 2023 191 17 95 41 54 2 4 5 2024 176 13 95 41 54 2 4 5 Thereafter 984 57 462 283 179 21 64 5 Total operating lease payments 2,036 156 969 500 469 31 85 30 Less: present value discount (396 ) (27 ) (177 ) (109 ) (68 ) (9 ) (27 ) (3 ) Total operating lease liabilities (a) $ 1,640 $ 129 $ 792 $ 391 $ 401 $ 22 $ 58 $ 27 (a) Certain operating lease payments include renewal options that are reasonably certain to be exercised.
Schedule of Future Minimum Rental Payments for Operating Leases	The following table presents future minimum lease payments under operating leases, which at inception had a noncancelable term of more than one year, as reported under the former lease standard. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2019 $ 239 $ 33 $ 97 $ 49 $ 48 $ 2 $ 6 $ 5 2020 219 29 90 46 44 2 5 5 2021 186 19 79 37 42 2 4 5 2022 170 19 76 34 42 2 4 5 2023 160 17 77 35 42 2 5 6 Thereafter 1,017 68 455 314 141 23 66 11 Total $ 1,991 $ 185 $ 874 $ 515 $ 359 $ 33 $ 90 $ 37
Maturities of Finance Lease Liabilities	The following table presents finance lease maturities and a reconciliation of the undiscounted cash flows to finance lease liabilities. December 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana 2020 $ 181 $ 28 $ 69 $ 44 $ 25 $ 1 2021 186 23 69 44 25 1 2022 173 23 69 44 25 1 2023 175 23 69 44 25 1 2024 121 23 55 44 11 1 Thereafter 823 314 539 528 11 27 Total finance lease payments 1,659 434 870 748 122 32 Less: amounts representing interest (690 ) (255 ) (465 ) (441 ) (24 ) (22 ) Total finance lease liabilities $ 969 $ 179 $ 405 $ 307 $ 98 $ 10
Schedule of Future Minimum Lease Payments for Capital Leases	The following table presents future minimum lease payments under finance leases, as reported under the former lease standard. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2019 $ 170 $ 20 $ 45 $ 20 $ 25 $ 2 $ 1 2020 174 20 46 21 25 — 1 2021 177 15 45 20 25 — 1 2022 165 15 45 21 24 — 1 2023 165 15 45 21 24 — 1 Thereafter 577 204 230 209 21 — 27 Minimum annual payments 1,428 289 456 312 144 2 32 Less: amount representing interest (487 ) (180 ) (205 ) (175 ) (30 ) — (22 ) Total $ 941 $ 109 $ 251 $ 137 $ 114 $ 2 $ 10
Supplemental Lease Information	December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Weighted average remaining lease term (years) Operating leases 11 9 10 12 8 17 18 6 Finance leases 13 19 16 18 11 — 26 — Weighted average discount rate (a) Operating leases 3.9 % 3.5 % 3.8 % 3.9 % 3.8 % 4.2 % 4.1 % 3.6 % Finance leases 8.1 % 11.8 % 11.9 % 12.4 % 8.3 % — % 11.9 % — % (a) The discount rate is calculated using the rate implicit in a lease if it is readily determinable. Generally, the rate used by the lessor is not provided to Duke Energy and in these cases the incremental borrowing rate is used. Duke Energy will typically use its fully collateralized incremental borrowing rate as of the commencement date to calculate and record the lease. The incremental borrowing rate is influenced by the lessee’s credit rating and lease term and as such may differ for individual leases, embedded leases or portfolios of leased assets.

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Debt	The following tables summarize outstanding debt. December 31, 2019 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unsecured debt, maturing 2020-2078 4.02 % $ 22,477 $ 1,150 $ 3,650 $ 700 $ 350 $ 1,110 $ 405 $ 2,399 Secured debt, maturing 2020-2052 3.30 % 4,537 544 1,722 335 1,387 — — — First mortgage bonds, maturing 2020-2049 (a) 4.13 % 27,977 9,557 13,800 7,575 6,225 1,449 3,169 — Finance leases, maturing 2022-2051 (b) 6.60 % 969 179 405 307 98 — 10 — Tax-exempt bonds, maturing 2022-2041 (c) 2.90 % 730 243 48 48 — 77 362 — Notes payable and commercial paper (d) 1.98 % 3,588 — — — — — — — Money pool/intercompany borrowings — 329 1,970 216 — 337 180 476 Fair value hedge carrying value adjustment 5 5 — — — — — — Unamortized debt discount and premium, net (e) 1,294 (23 ) (29 ) (17 ) (11 ) (30 ) (19 ) (2 ) Unamortized debt issuance costs (f) (316 ) (55 ) (111 ) (40 ) (62 ) (12 ) (20 ) (13 ) Total debt 3.92 % $ 61,261 $ 11,929 $ 21,455 $ 9,124 $ 7,987 $ 2,931 $ 4,087 $ 2,860 Short-term notes payable and commercial paper (3,135 ) — — — — — — — Short-term money pool/intercompany borrowings — (29 ) (1,821 ) (66 ) — (312 ) (30 ) (476 ) Current maturities of long-term debt (g) (3,141 ) (458 ) (1,577 ) (1,006 ) (571 ) — (503 ) — Total long-term debt (g) $ 54,985 $ 11,442 $ 18,057 $ 8,052 $ 7,416 $ 2,619 $ 3,554 $ 2,384 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $44 million and $419 million of finance lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to PPAs that are not accounted for as finance leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds, letters of credit or the Master Credit Facility. (d) Includes $625 million classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy's commercial paper program was 14 days. (e) Duke Energy includes $1,275 million and $137 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively. (f) Duke Energy includes $37 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (g) Refer to Note 18 for additional information on amounts from consolidated VIEs. December 31, 2018 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unsecured debt, maturing 2019-2078 4.26 % $ 20,955 $ 1,150 $ 3,800 $ 50 $ 350 $ 1,000 $ 408 $ 2,150 Secured debt, maturing 2020-2037 3.69 % 4,297 450 1,703 300 1,403 — — — First mortgage bonds, maturing 2019-2048 (a) 4.32 % 25,628 8,759 13,100 7,574 5,526 1,099 2,670 — Finance leases, maturing 2019-2051 (b) 5.06 % 941 109 251 137 114 2 10 — Tax-exempt bonds, maturing 2019-2041 (c) 3.40 % 941 243 48 48 — 77 572 — Notes payable and commercial paper (d) 2.73 % 4,035 — — — — — — — Money pool/intercompany borrowings — 739 1,385 444 108 299 317 198 Fair value hedge carrying value adjustment 5 5 — — — — — — Unamortized debt discount and premium, net (e) 1,434 (23 ) (29 ) (15 ) (11 ) (31 ) (8 ) (1 ) Unamortized debt issuance costs (f) (297 ) (54 ) (112 ) (40 ) (61 ) (7 ) (20 ) (11 ) Total debt 4.13 % $ 57,939 $ 11,378 $ 20,146 $ 8,498 $ 7,429 $ 2,439 $ 3,949 $ 2,336 Short-term notes payable and commercial paper (3,410 ) — — — — — — — Short-term money pool/intercompany borrowings — (439 ) (1,235 ) (294 ) (108 ) (274 ) (167 ) (198 ) Current maturities of long-term debt (g) (3,406 ) (6 ) (1,672 ) (603 ) (270 ) (551 ) (63 ) (350 ) Total long-term debt (g) $ 51,123 $ 10,933 $ 17,239 $ 7,601 $ 7,051 $ 1,614 $ 3,719 $ 1,788 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $63 million and $531 million of finance lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to PPAs that are not accounted for as finance leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds, letters of credit or the Master Credit Facility. (d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy's commercial paper programs was 16 days. (e) Duke Energy includes $1,380 million and $156 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively. (f) Duke Energy includes $41 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (g) Refer to Note 18 for additional information on amounts from consolidated VIEs. December 31, 2019 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 312 $ — $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 937 $ 300 $ 150 $ 52 $ 435 December 31, 2018 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 312 $ — $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 937 $ 300 $ 150 $ 52 $ 435 (a) Progress Energy amounts are equal to Duke Energy Progress amounts. The following table shows the significant components of Current maturities of Long-Term Debt on the Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate December 31, 2019 Unsecured Debt Duke Energy (Parent) June 2020 2.100 % $ 330 Duke Energy Progress December 2020 2.510 % (a) 700 First Mortgage Bonds Duke Energy Florida January 2020 1.850 % 250 Duke Energy Florida April 2020 4.550 % 250 Duke Energy Carolinas June 2020 4.300 % 450 Duke Energy Indiana July 2020 3.750 % 500 Duke Energy Progress September 2020 2.065 % (a) 300 Other (b) 361 Current maturities of long-term debt $ 3,141 (a) Debt has a floating interest rate. (b) Includes finance lease obligations, amortizing debt and small bullet maturities.
Schedule of Maturities of Long-term Debt	The following table shows the annual maturities of long-term debt for the next five years and thereafter. Amounts presented exclude short-term notes payable, commercial paper and money pool borrowings and debt issuance costs for the Subsidiary Registrants. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy (a) Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 3,141 $ 458 $ 1,578 $ 1,006 $ 572 — $ 503 $ — 2021 5,053 504 2,257 932 825 50 70 160 2022 4,334 830 1,048 508 90 — 94 — 2023 3,112 1,006 398 319 79 325 3 45 2024 1,965 306 227 160 67 25 154 40 Thereafter 39,542 8,875 14,267 6,190 6,427 2,261 3,272 2,155 Total long-term debt, including current maturities $ 57,147 $ 11,979 $ 19,775 $ 9,115 $ 8,060 $ 2,661 $ 4,096 $ 2,400 (a) Excludes $1,448 million in purchase accounting adjustments related to the Progress Energy merger and the Piedmont acquisition.
Schedule of Long-term Debt Instruments	The following tables summarize significant debt issuances (in millions). Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Unsecured Debt March 2019 (a) Mar 2022 2.538 % (b) $ 300 $ 300 $ — $ — $ — $ — $ — $ — March 2019 (a) Mar 2022 3.227 % 300 300 — — — — — — May 2019 (e) Jun 2029 3.500 % 600 — — — — — — 600 June 2019 (a) Jun 2029 3.400 % 600 600 — — — — — — June 2019 (a) Jun 2049 4.200 % 600 600 — — — — — — July 2019 (g) Jul 2049 4.320 % 40 — — — — 40 — — September 2019 (g) Oct 2025 3.230 % 95 — — — — 95 — — September 2019 (g) Oct 2029 3.560 % 75 — — — — 75 — — November 2019 (h) Nov 2021 2.167 % (b) 200 — — — 200 — — — First Mortgage Bonds January 2019 (c) Feb 2029 3.650 % 400 — — — — 400 — — January 2019 (c) Feb 2049 4.300 % 400 — — — — 400 — — March 2019 (d) Mar 2029 3.450 % 600 — — 600 — — — — August 2019 (a) Aug 2029 2.450 % 450 — 450 — — — — — August 2019 (a) Aug 2049 3.200 % 350 — 350 — — — — — September 2019 (f) Oct 2049 3.250 % 500 — — — — — 500 — November 2019 (i) Dec 2029 2.500 % 700 — — — 700 — — — Total issuances $ 6,210 $ 1,800 $ 800 $ 600 $ 900 $ 1,010 $ 500 $ 600 (a) Debt issued to pay down short-term debt and for general corporate purposes. (b) Debt issuance has a floating interest rate. (c) Debt issued to repay at maturity $450 million first mortgage bonds due April 2019, pay down short-term debt and for general corporate purposes. (d) Debt issued to fund eligible green energy projects in the Carolinas. (e) Debt issued to repay in full the outstanding $350 million Piedmont unsecured term loan due September 2019, pay down short-term debt and for general corporate purposes. (f) Debt issued to retire $150 million of pollution control bonds, pay down short-term debt and for general corporate purposes. (g) Debt issued to repay at maturity $100 million debentures due October 2019, pay down short-term debt and for general corporate purposes. (h) Debt issued to fund storm restoration costs and for general corporate purposes. (i) Debt issued to reimburse the payment of existing and new Eligible Green Expenditures in Florida. In January 2020, Duke Energy Carolinas closed and funded $900 million of first mortgage bonds of which $500 million carry a fixed interest rate of 2.45% and mature February 2030 and $400 million carry a fixed interest rate of 3.20% and mature August 2049. The proceeds will be used to repay at maturity $450 million , 4.30% debentures maturing June 2020, and for general corporate purposes. Year Ended December 31, 2018 Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Unsecured Debt March 2018 (a) April 2025 3.950 % $ 250 $ 250 $ — $ — $ — May 2018 (b) May 2021 3.114 % 500 500 — — — September 2018 (c) September 2078 5.625 % 500 500 — — — First Mortgage Bonds March 2018 (d) March 2023 3.050 % 500 — 500 — — March 2018 (d) March 2048 3.950 % 500 — 500 — — June 2018 (e) July 2028 3.800 % 600 — — — 600 June 2018 (e) July 2048 4.200 % 400 — — — 400 August 2018 (f) September 2023 3.375 % 300 — — 300 — August 2018 (f) September 2028 3.700 % 500 — — 500 — November 2018 (g) May 2022 3.350 % 350 — 350 — — November 2018 (g) November 2028 3.950 % 650 — 650 — — Total issuances $ 5,050 $ 1,250 $ 2,000 $ 800 $ 1,000 (a) Debt issued to pay down short-term debt. (b) Debt issued to pay down short-term debt. Debt issuance has a floating debt rate. (c) Callable after September 2023 at par. Junior subordinated hybrid debt issued to pay down short-term debt and for general corporate purposes. (d) Debt issued to repay at maturity a $300 million first mortgage bond due April 2018, pay down intercompany short-term debt and for general corporate purposes. (e) Debt issued to repay a portion of intercompany short-term debt under the money pool borrowing arrangement and for general corporate purposes. (f) Debt issued to repay short-term debt and for general corporate purposes. (g) Debt issued to fund eligible green energy projects, including zero-carbon solar and energy storage, in the Carolinas.
Schedule Of Line Of Credit Facilities	The table below includes the current borrowing sublimits and available capacity under these credit facilities. December 31, 2019 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Facility size (a) $ 8,000 $ 2,650 $ 1,500 $ 1,250 $ 800 $ 600 $ 600 $ 600 Reduction to backstop issuances Commercial paper (b) (2,537 ) (1,119 ) (325 ) (207 ) — (296 ) (176 ) (414 ) Outstanding letters of credit (50 ) (42 ) (4 ) (2 ) — — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity $ 4,832 $ 1,489 $ 921 $ 791 $ 800 $ 304 $ 343 $ 184 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Consolidated Balance Sheets.

Joint Ownership of Generating_2

Joint Ownership of Generating and Transmission Facilities (Tables)	12 Months Ended
	Dec. 31, 2019
Joint Ownership Of Generating And Transmission Facilities [Abstract]
Schedule Joint Ownership of Generating and Transmission Facilities	The following table presents the Duke Energy Registrants' interest of jointly owned plant or facilities and amounts included on the Consolidated Balance Sheets. All facilities are operated by the Duke Energy Registrants and are included in the Electric Utilities and Infrastructure segment. December 31, 2019 Construction Ownership Property, Plant Accumulated Work in (in millions except for ownership interest) Interest and Equipment Depreciation Progress Duke Energy Carolinas Catawba (units 1 and 2) (a) 19.25 % $ 1,011 $ 510 $ 21 W.S. Lee CC (b) 87.27 % 609 32 1 Duke Energy Indiana Gibson (unit 5) (c) 50.05 % 410 183 3 Vermillion (d) 62.50 % 172 119 — Transmission and local facilities (c) Various 5,421 1,436 172 (a) Jointly owned with North Carolina Municipal Power Agency Number 1, NCEMC and PMPA. (b) Jointly owned with NCEMC. (c) Jointly owned with WVPA and IMPA. (d) Jointly owned with WVPA.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Asset Retirement Obligations by Category	The following table presents the AROs recorded on the Consolidated Balance Sheets. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Decommissioning of nuclear power facilities (a) $ 6,633 $ 2,551 $ 4,028 $ 3,499 $ 529 $ — $ — $ — Closure of ash impoundments 6,333 3,118 2,368 2,352 16 41 805 — Other 352 65 75 42 33 39 27 17 Total asset retirement obligation $ 13,318 $ 5,734 $ 6,471 $ 5,893 $ 578 $ 80 $ 832 $ 17 Less: current portion 881 206 485 485 — 1 189 — Total noncurrent asset retirement obligation $ 12,437 $ 5,528 $ 5,986 $ 5,408 $ 578 $ 79 $ 643 $ 17 (a) Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy.
Public Utilities General Disclosures	The following table includes the current expiration of nuclear operating licenses. Unit Year of Expiration Duke Energy Carolinas Catawba Units 1 and 2 2043 McGuire Unit 1 2041 McGuire Unit 2 2043 Oconee Units 1 and 2 2033 Oconee Unit 3 2034 Duke Energy Progress Brunswick Unit 1 2036 Brunswick Unit 2 2034 Harris 2046 Robinson 2030 The following table presents the fair value of NDTF assets legally restricted for purposes of settling AROs associated with nuclear decommissioning. Duke Energy Florida is actively decommissioning Crystal River Unit 3 and was granted an exemption from the NRC, which allows for use of the NDTF for all aspects of nuclear decommissioning. The entire balance of Duke Energy Florida's NDTF may be applied toward license termination, spent fuel and site restoration costs incurred to decommission Crystal River Unit 3 and is excluded from the table below. See Note 17 for additional information related to the fair value of the Duke Energy Registrants' NDTFs. December 31, (in millions) 2019 2018 Duke Energy $ 6,766 $ 5,579 Duke Energy Carolinas 3,837 3,133 Duke Energy Progress 2,929 2,446 The following table summarizes information about the most recent site-specific nuclear decommissioning cost studies. Decommissioning costs are stated in 2018 or 2019 dollars, depending on the year of the cost study, and include costs to decommission plant components not subject to radioactive contamination. Annual Funding Decommissioning (in millions) Requirement (a) Costs (a) Year of Cost Study Duke Energy $ 24 $ 9,152 2018 and 2019 Duke Energy Carolinas (b)(c) — 4,365 2018 Duke Energy Progress (d) 24 4,181 2019 Duke Energy Florida (e) — 606 2019 (a) Amounts for Progress Energy equal the sum of Duke Energy Progress and Duke Energy Florida. (b) Decommissioning cost for Duke Energy Carolinas reflects its ownership interest in jointly owned reactors. Other joint owners are responsible for decommissioning costs related to their interest in the reactors. (c) Duke Energy Carolinas' site-specific nuclear decommissioning cost study completed in 2018 was filed with the NCUC and PSCSC in 2019. A new funding study was also completed and filed with the NCUC and PSCSC in 2019. (d) Duke Energy Progress' site-specific nuclear decommissioning cost study completed in 2019 is expected to be filed with the NCUC and PSCSC during the first quarter 2020. Duke Energy Progress will also complete a new funding study, which will be completed and filed with the NCUC and PSCSC in July 2020. (e)
Rollforward Schedule of Asset Retirement Obligations	The following tables present changes in the liability associated with AROs. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at December 31, 2017 $ 10,175 $ 3,610 $ 5,414 $ 4,673 $ 742 $ 84 $ 781 $ 15 Accretion expense (a) 427 179 225 196 29 4 29 1 Liabilities settled (b) (638 ) (281 ) (272 ) (227 ) (45 ) (5 ) (79 ) — Liabilities incurred in the current year (c) 39 8 5 — 5 — 25 — Revisions in estimates of cash flows 464 433 39 178 (140 ) 10 (34 ) 3 Balance at December 31, 2018 10,467 3,949 5,411 4,820 591 93 722 19 Accretion expense (a) 508 235 252 227 25 3 28 1 Liabilities settled (b) (895 ) (329 ) (499 ) (460 ) (39 ) (12 ) (54 ) — Liabilities incurred in the current year 25 18 7 — 7 — — — Revisions in estimates of cash flows (d) 3,213 1,861 1,300 1,306 (6 ) (4 ) 136 (3 ) Balance at December 31, 2019 $ 13,318 $ 5,734 $ 6,471 $ 5,893 $ 578 $ 80 $ 832 $ 17 (a) Substantially all accretion expense for the years ended December 31, 2019 , and 2018 , relates to Duke Energy’s regulated operations and has been deferred in accordance with regulatory accounting treatment. (b) Amounts primarily relate to ash impoundment closures and nuclear decommissioning of Crystal River Unit 3. (c) Amounts primarily relate to AROs recorded as a result of state agency closure requirements at Duke Energy Indiana. (d) Amounts primarily relate to increases in closure estimates for certain ash impoundments as a result of the NCDEQ's April 1 Order and the related settlement agreement dated December 31, 2019. See Note 5 for more information. The amount recorded in the fourth quarter of 2019 for coal ash closures as a result of the settlement was not material.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2019 2018 2017 Duke Energy 3.1 % 3.0 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.8 % Progress Energy 3.1 % 2.9 % 2.6 % Duke Energy Progress 3.1 % 2.9 % 2.6 % Duke Energy Florida 3.1 % 3.0 % 2.8 % Duke Energy Ohio 2.6 % 2.8 % 2.8 % Duke Energy Indiana 3.3 % 3.3 % 3.0 % Piedmont 2.4 % 2.5 % 2.3 % The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants. December 31, 2019 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Land $ 2,091 $ 520 $ 884 $ 449 $ 435 $ 150 $ 117 $ 388 Plant – Regulated Electric generation, distribution and transmission 15-100 111,739 42,723 48,142 30,018 18,124 5,838 15,032 — Natural gas transmission and distribution 4-73 9,839 — — — — 2,892 — 6,947 Other buildings and improvements 23-90 1,810 714 401 162 239 269 278 148 Plant – Nonregulated Electric generation, distribution and transmission 5-30 5,103 — — — — — — — Other buildings and improvements 25-35 488 — — — — — — — Nuclear fuel 3,253 1,891 1,362 1,362 — — — — Equipment 3-25 2,313 546 665 452 213 319 205 128 Construction in process 6,102 1,389 2,149 1,114 1,035 504 381 531 Other 2-40 4,916 1,139 1,467 1,046 411 269 292 304 Total property, plant and equipment (a)(e) 147,654 48,922 55,070 34,603 20,457 10,241 16,305 8,446 Total accumulated depreciation – regulated (b)(c) (43,419 ) (16,525 ) (17,159 ) (11,915 ) (5,236 ) (2,843 ) (5,233 ) (1,681 ) Total accumulated depreciation – nonregulated (d)(e) (2,354 ) — — — — — — — Generation facilities to be retired, net 246 — 246 246 — — — — Total net property, plant and equipment $ 102,127 $ 32,397 $ 38,157 $ 22,934 $ 15,221 $ 7,398 $ 11,072 $ 6,765 (a) Includes finance leases of $952 million , $211 million , $443 million , $308 million , $135 million and $10 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $143 million , $17 million and $126 million , respectively, of accumulated amortization of finance leases. (b) Includes $1,807 million , $1,082 million , $725 million and $725 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of finance leases of $6 million , $13 million and $3 million at Duke Energy, Duke Energy Carolinas and Duke Energy Indiana, respectively. (d) Includes accumulated amortization of finance leases of $20 million at Duke Energy. (e) Includes gross property, plant and equipment cost of consolidated VIEs of $5,747 million and accumulated depreciation of consolidated VIEs of $1,041 million at Duke Energy. December 31, 2018 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Land $ 2,072 $ 472 $ 868 $ 445 $ 423 $ 136 $ 116 $ 448 Plant – Regulated Electric generation, distribution and transmission 15-100 100,706 38,468 42,760 26,147 16,613 5,182 14,292 — Natural gas transmission and distribution 12-80 8,808 — — — — 2,719 — 6,089 Other buildings and improvements 24-90 1,966 681 636 295 341 270 253 126 Plant – Nonregulated Electric generation, distribution and transmission 5-30 4,410 — — — — — — — Other buildings and improvements 25-35 494 — — — — — — — Nuclear fuel 3,460 1,898 1,562 1,562 — — — — Equipment 3-55 2,141 467 565 399 166 384 178 141 Construction in process 5,726 1,678 2,515 1,659 856 412 325 382 Other 3-40 4,675 1,077 1,354 952 393 257 279 300 Total property, plant and equipment (a)(d) 134,458 44,741 50,260 31,459 18,792 9,360 15,443 7,486 Total accumulated depreciation – regulated (b)(c)(d) (41,079 ) (15,496 ) (16,398 ) (11,423 ) (4,968 ) (2,717 ) (4,914 ) (1,575 ) Total accumulated depreciation – nonregulated (c)(d) (2,047 ) — — — — — — — Generation facilities to be retired, net 362 — 362 362 — — — — Total net property, plant and equipment $ 91,694 $ 29,245 $ 34,224 $ 20,398 $ 13,824 $ 6,643 $ 10,529 $ 5,911 (a) Includes finance leases of $1,237 million , $135 million , $257 million , $137 million , $120 million , $73 million and $35 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $131 million , $14 million and $117 million , respectively, of accumulated amortization of finance leases. (b) Includes $1,947 million , $1,087 million , $860 million and $860 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of finance leases of $61 million , $12 million , $20 million and $10 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $4,007 million and accumulated depreciation of consolidated VIEs of $698 million at Duke Energy.
Schedule Of Capitalized Interest	The following tables present capitalized interest, which includes the debt component of AFUDC. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy $ 159 $ 161 $ 128 Duke Energy Carolinas 30 35 45 Progress Energy 31 51 45 Duke Energy Progress 28 26 21 Duke Energy Florida 3 25 24 Duke Energy Ohio 22 17 10 Duke Energy Indiana 26 27 9 Piedmont 26 17 12

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill By Reportable Operating Segment	The following table presents goodwill by reportable segment for Duke Energy included on Duke Energy's Consolidated Balance Sheets at December 31, 2019 , and 2018 . Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill Balance at December 31, 2018 $ 17,379 $ 1,924 $ 122 $ 19,425 Accumulated impairment charges (a) — — (122 ) (122 ) Goodwill balance at December 31, 2018, adjusted for accumulated impairment charges $ 17,379 $ 1,924 $ — $ 19,303 Goodwill Balance at December 31, 2019 $ 17,379 $ 1,924 $ 122 $ 19,425 Accumulated impairment charges (a) — — (122 ) (122 ) Goodwill balance at December 31, 2019, adjusted for accumulated impairment charges $ 17,379 $ 1,924 $ — $ 19,303 (a) Duke Energy evaluated the recoverability of goodwill during 2018 and 2017 and recorded impairment charges of $93 million and $29 million , respectively, related to the Commercial Renewables reporting unit included in Impairment charges on Duke Energy’s Consolidated Statements of Operations. The fair value of the reporting unit was determined based on the income approach and market approach in 2018 and 2017, respectively. See "Goodwill Impairment Testing" below for the results of the 2019 goodwill impairment test.
Schedule of Intangible Assets	The following tables show the carrying amount and accumulated amortization of intangible assets included in Other within Other Noncurrent Assets on the Consolidated Balance Sheets of the Duke Energy Registrants at December 31, 2019 , and 2018 . December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Emission allowances $ 18 $ — $ 5 $ 2 $ 3 $ — $ 12 $ — Renewable energy certificates 172 53 118 118 — 1 — — Natural gas, coal and power contracts 24 — — — — — 24 — Renewable operating and development projects 89 — — — — — — — Other 2 — — — — — — — Total gross carrying amounts 305 53 123 120 3 1 36 — Accumulated amortization – natural gas, coal and power contracts (21 ) — — — — — (21 ) — Accumulated amortization – renewable operating and development projects (34 ) — — — — — — — Accumulated amortization – other (1 ) — — — — — — — Total accumulated amortization (56 ) — — — — — (21 ) — Total intangible assets, net $ 249 $ 53 $ 123 $ 120 $ 3 $ 1 $ 15 $ — December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Emission allowances $ 18 $ — $ 5 $ 2 $ 3 $ — $ 12 $ — Renewable energy certificates 168 46 120 120 — 2 — — Natural gas, coal and power contracts 24 — — — — — 24 — Renewable operating and development projects 84 — — — — — — — Other 6 — — — — — — 3 Total gross carrying amounts 300 46 125 122 3 2 36 3 Accumulated amortization – natural gas, coal and power contracts (20 ) — — — — — (20 ) — Accumulated amortization – renewable operating and development projects (29 ) — — — — — — — Accumulated amortization – other (5 ) — — — — — — (3 ) Total accumulated amortization (54 ) — — — — — (20 ) (3 ) Total intangible assets, net $ 246 $ 46 $ 125 $ 122 $ 3 $ 2 $ 16 $ —

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investments in Equity Method Unconsolidated Affiliates	The following table presents Duke Energy’s investments in unconsolidated affiliates accounted for under the equity method, as well as the respective equity in earnings, by segment. Years Ended December 31, 2019 2018 2017 Equity in Equity in Equity in (in millions) Investments earnings Investments earnings Investments earnings Electric Utilities and Infrastructure $ 122 $ 9 $ 97 $ 6 $ 89 $ 5 Gas Utilities and Infrastructure 1,388 114 1,003 27 763 62 Commercial Renewables 314 (4 ) 201 (1 ) 190 (5 ) Other 112 43 108 51 133 57 Total $ 1,936 $ 162 $ 1,409 $ 83 $ 1,175 $ 119 The table below outlines Duke Energy's ownership interests in natural gas pipeline companies and natural gas storage facilities. Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest 2019 2018 Pipeline Investments ACP 47 % $ 1,179 $ 797 Sabal Trail 7.5 % 121 112 (c) Constitution 24 % — 25 Cardinal (a) 21.49 % 9 10 Storage Facilities Pine Needle (a) 45 % 28 13 Hardy Storage (a) 50 % 51 46 Total Investments (b) $ 1,388 $ 1,003 (a) Piedmont owns the Cardinal, Pine Needle and Hardy Storage investments. (b) Duke Energy includes purchase accounting adjustments related to Piedmont. (c) Sabal Trail returned capital of $112 million during the year ended December 31, 2018.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 841 $ 985 $ 858 Indemnification coverages (b) 20 22 23 Joint Dispatch Agreement (JDA) revenue (c) 60 84 49 JDA expense (c) 186 207 145 Intercompany natural gas purchases (d) 15 15 9 Progress Energy Corporate governance and shared service expenses (a) $ 778 $ 906 $ 736 Indemnification coverages (b) 37 34 38 JDA revenue (c) 186 207 145 JDA expense (c) 60 84 49 Intercompany natural gas purchases (d) 76 78 77 Duke Energy Progress Corporate governance and shared service expenses (a) $ 462 $ 577 $ 438 Indemnification coverages (b) 15 13 15 JDA revenue (c) 186 207 145 JDA expense (c) 60 84 49 Intercompany natural gas purchases (d) 76 78 77 Duke Energy Florida Corporate governance and shared service expenses (a) $ 316 $ 329 $ 298 Indemnification coverages (b) 22 21 23 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 354 $ 374 $ 363 Indemnification coverages (b) 4 5 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 412 $ 405 $ 370 Indemnification coverages (b) 7 7 8 Piedmont Corporate governance and shared service expenses (a) $ 138 $ 170 $ 50 Indemnification coverages (b) 3 2 2 Intercompany natural gas sales (d) 91 93 86 Natural gas storage and transportation costs (e) 23 25 25 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA, which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power pursuant to the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress natural gas-fired generation facilities. Piedmont records the sales in Operating Revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases as a component of Fuel used in electric generation and purchased power on their respective Consolidated Statements of Operations and Comprehensive Income. These intercompany revenues and expenses are eliminated in consolidation. (e) Piedmont has related party transactions as a customer of its equity method investments in Pine Needle, Hardy Storage, and Cardinal natural gas storage and transportation facilities. These expenses are included in Cost of natural gas on Piedmont's Consolidated Statements of Operations and Comprehensive Income. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont December 31, 2019 Intercompany income tax receivable $ — $ 125 $ 28 $ — $ 9 $ 28 $ 13 Intercompany income tax payable 5 — — 2 — — — December 31, 2018 Intercompany income tax receivable $ 52 $ 47 $ 29 $ — $ — $ 8 $ — Intercompany income tax payable — — — 16 3 — 45

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	The following tables show notional amounts of outstanding derivatives related to interest rate risk. December 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 993 $ — $ — $ — $ — $ — Undesignated contracts 1,277 450 800 250 550 27 Total notional amount (a) $ 2,270 $ 450 $ 800 $ 250 $ 550 $ 27 December 31, 2018 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 923 $ — $ — $ — $ — $ — Undesignated contracts 1,721 300 1,200 650 550 27 Total notional amount $ 2,644 $ 300 $ 1,200 $ 650 $ 550 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $693 million in cash flow hedges as of December 31, 2019 , and $422 million in cash flow hedges and $194 million in undesignated contracts as of December 31, 2018 . The tables below include volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. The Duke Energy Registrants have netted contractual amounts where offsetting purchase and sale contracts exist with identical delivery locations and times of delivery. Where all commodity positions are perfectly offset, no quantities are shown. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 15,858 — — — — 1,887 13,971 — Natural gas (millions of Dth) 704 130 160 160 — — 3 411 December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 15,286 — — — — 1,786 13,500 — Natural gas (millions of Dth) 739 121 169 166 3 — 1 448
Location and Fair Value of Derivatives Recognized in the Consolidated Balance Sheets	The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 17 $ — $ — $ — $ — $ 3 $ 13 $ 1 Noncurrent 1 — — — — 1 — — Total Derivative Assets – Commodity Contracts $ 18 $ — $ — $ — $ — $ 4 $ 13 $ 1 Interest Rate Contracts Not Designated as Hedging Instruments Current 6 — 6 — 6 — — — Total Derivative Assets – Interest Rate Contracts $ 6 $ — $ 6 $ — $ 6 $ — $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 1 — 1 — 1 — — — Total Derivative Assets – Equity Securities Contracts $ 1 $ — $ 1 $ — $ 1 $ — $ — $ — Total Derivative Assets $ 25 $ — $ 7 $ — $ 7 $ 4 $ 13 $ 1 Derivative Liabilities December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 67 $ 33 $ 26 $ 26 $ — $ — $ 1 $ 7 Noncurrent 156 10 37 22 — — — 110 Total Derivative Liabilities – Commodity Contracts $ 223 $ 43 $ 63 $ 48 $ — $ — $ 1 $ 117 Interest Rate Contracts Designated as Hedging Instruments Current $ 19 $ — $ — $ — $ — $ — $ — $ — Noncurrent 21 — — — — — — — Not Designated as Hedging Instruments Current 8 6 1 1 — 1 — — Noncurrent 5 — — — — 5 — — Total Derivative Liabilities – Interest Rate Contracts $ 53 $ 6 $ 1 $ 1 $ — $ 6 $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 24 — 24 — 24 — — — Total Derivative Liabilities – Equity Security Contracts $ 24 $ — $ 24 $ — $ 24 $ — $ — $ — Total Derivative Liabilities $ 300 $ 49 $ 88 $ 49 $ 24 $ 6 $ 1 $ 117 Derivative Assets December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 35 $ 2 $ 2 $ 2 $ — $ 6 $ 23 $ 3 Noncurrent 4 1 2 2 — — — — Total Derivative Assets – Commodity Contracts $ 39 $ 3 $ 4 $ 4 $ — $ 6 $ 23 $ 3 Interest Rate Contracts Designated as Hedging Instruments Current $ 1 $ — $ — $ — $ — $ — $ — $ — Noncurrent 3 — — — — — — — Not Designated as Hedging Instruments Current 2 — — — — — — — Noncurrent 12 — — — — — — — Total Derivative Assets – Interest Rate Contracts $ 18 $ — $ — $ — $ — $ — $ — $ — Total Derivative Assets $ 57 $ 3 $ 4 $ 4 $ — $ 6 $ 23 $ 3 Derivative Liabilities December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 33 $ 14 $ 10 $ 5 $ 6 $ — $ — $ 8 Noncurrent 158 10 15 6 — — — 133 Total Derivative Liabilities – Commodity Contracts $ 191 $ 24 $ 25 $ 11 $ 6 $ — $ — $ 141 Interest Rate Contracts Designated as Hedging Instruments Current $ 12 $ — $ — $ — $ — $ — $ — $ — Noncurrent 6 — — — — — — — Not Designated as Hedging Instruments Current 23 9 13 11 2 1 — — Noncurrent 10 — 6 5 1 4 — — Total Derivative Liabilities – Interest Rate Contracts $ 51 $ 9 $ 19 $ 16 $ 3 $ 5 $ — $ — Total Derivative Liabilities $ 242 $ 33 $ 44 $ 27 $ 9 $ 5 $ — $ 141
Offsetting Assets	The following tables present the line items on the Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The gross amounts offset in the tables below show the effect of these netting arrangements on financial position and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 24 $ — $ 7 $ — $ 7 $ 3 $ 13 $ 1 Gross amounts offset (1 ) — (1 ) — (1 ) — — — Net amounts presented in Current Assets: Other $ 23 $ — $ 6 $ — $ 6 $ 3 $ 13 $ 1 Noncurrent Gross amounts recognized $ 1 $ — $ — $ — $ — $ 1 $ — $ — Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Assets: Other $ 1 $ — $ — $ — $ — $ 1 $ — $ — Derivative Assets December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 38 $ 2 $ 2 $ 2 $ — $ 6 $ 23 $ 3 Gross amounts offset (3 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Assets: Other $ 35 $ — $ — $ — $ — $ 6 $ 23 $ 3 Noncurrent Gross amounts recognized $ 19 $ 1 $ 2 $ 2 $ — $ — $ — $ — Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 16 $ — $ — $ — $ — $ — $ — $ —
Offsetting Liabilities	Derivative Liabilities December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 68 $ 23 $ 23 $ 16 $ 8 $ 1 $ — $ 8 Gross amounts offset (4 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Liabilities: Other $ 64 $ 21 $ 21 $ 14 $ 8 $ 1 $ — $ 8 Noncurrent Gross amounts recognized $ 174 $ 10 $ 21 $ 11 $ 1 $ 4 $ — $ 133 Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 171 $ 9 $ 19 $ 9 $ 1 $ 4 $ — $ 133 Derivative Liabilities December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 118 $ 39 $ 51 $ 27 $ 24 $ 1 $ 1 $ 7 Gross amounts offset (24 ) — (24 ) — (24 ) — — — Net amounts presented in Current Liabilities: Other $ 94 $ 39 $ 27 $ 27 $ — $ 1 $ 1 $ 7 Noncurrent Gross amounts recognized $ 182 $ 10 $ 37 $ 22 $ — $ 5 $ — $ 110 Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 182 $ 10 $ 37 $ 22 $ — $ 5 $ — $ 110
Derivative Contracts with Contingent Credit Features	The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. December 31, 2019 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 79 $ 35 $ 44 $ 44 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 79 35 44 44 December 31, 2018 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 44 $ 19 $ 25 $ 25 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 44 19 25 25 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative and cash collateral must be executed with the same counterparty under the same master netting arrangement.

Investments in Debt and Equit_2

Investments in Debt and Equity Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Investment [Line Items]
Summary of Investments in Debt and Equity Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 101 $ — $ — $ 88 Equity securities 3,523 55 5,661 2,402 95 4,475 Corporate debt securities 37 1 603 4 13 566 Municipal bonds 13 — 368 1 4 353 U.S. government bonds 33 1 1,256 14 12 1,076 Other debt securities 3 — 141 — 2 148 Total NDTF Investments $ 3,609 $ 57 $ 8,130 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 22 Equity securities 57 — 122 36 1 99 Corporate debt securities 3 — 67 — 2 60 Municipal bonds 4 — 94 — 1 85 U.S. government bonds 2 — 41 1 — 45 Other debt securities — — 56 — 1 58 Total Other Investments $ 66 $ — $ 432 $ 37 $ 5 $ 369 Total Investments $ 3,675 $ 57 $ 8,562 $ 2,458 $ 131 $ 7,075
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 372 Due after one through five years 550 Due after five through 10 years 452 Due after 10 years 1,252 Total $ 2,626
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 172 $ 168 Realized losses 151 126 AFS: Realized gains 94 22 Realized losses 67 51 Year Ended December 31, (in millions) 2017 Realized gains $ 202 Realized losses 160
Duke Energy Carolinas
Investment [Line Items]
Summary of Investments in Debt and Equity Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 21 $ — $ — $ 29 Equity securities 1,914 8 3,154 1,309 54 2,484 Corporate debt securities 21 1 361 2 9 341 Municipal bonds 3 — 96 — 1 81 U.S. government bonds 16 1 578 5 8 475 Other debt securities 3 — 137 — 2 143 Total NDTF Investments $ 1,957 $ 10 $ 4,347 $ 1,316 $ 74 $ 3,553
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 51 Due after one through five years 253 Due after five through 10 years 181 Due after 10 years 687 Total $ 1,172
Schedule of Realized Gain (Loss)	Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 113 $ 89 Realized losses 107 73 AFS: Realized gains 55 19 Realized losses 38 35 Year Ended December 31, (in millions) 2017 Realized gains $ 135 Realized losses 103
Progress Energy
Investment [Line Items]
Summary of Investments in Debt and Equity Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 80 $ — $ — $ 59 Equity securities 1,609 47 2,507 1,093 41 1,991 Corporate debt securities 16 — 242 2 4 225 Municipal bonds 10 — 272 1 3 272 U.S. government bonds 17 — 678 9 4 601 Other debt securities — — 4 — — 5 Total NDTF Investments $ 1,652 $ 47 $ 3,783 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 49 $ — $ — $ 17 Municipal bonds 3 — 51 — — 47 Total Other Investments $ 3 $ — $ 100 $ — $ — $ 64 Total Investments $ 1,655 $ 47 $ 3,883 $ 1,105 $ 52 $ 3,217
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 311 Due after one through five years 256 Due after five through 10 years 211 Due after 10 years 469 Total $ 1,247
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 59 $ 79 Realized losses 44 53 AFS: Realized gains 36 3 Realized losses 29 15 Year Ended December 31, (in millions) 2017 Realized gains $ 65 Realized losses 56
Duke Energy Progress
Investment [Line Items]
Summary of Investments in Debt and Equity Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 53 $ — $ — $ 46 Equity securities 1,258 21 2,077 833 30 1,588 Corporate debt securities 16 — 242 2 3 171 Municipal bonds 10 — 272 1 3 271 U.S. government bonds 16 — 403 6 3 415 Other debt securities — — 4 — — 3 Total NDTF Investments $ 1,300 $ 21 $ 3,051 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Total Other Investments $ — $ — $ 2 $ — $ — $ 6 Total Investments $ 1,300 $ 21 $ 3,053 $ 842 $ 39 $ 2,500
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 34 Due after one through five years 247 Due after five through 10 years 204 Due after 10 years 436 Total $ 921
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 38 $ 68 Realized losses 33 48 AFS: Realized gains 7 2 Realized losses 5 10 Year Ended December 31, (in millions) 2017 Realized gains $ 54 Realized losses 48
Duke Energy Florida
Investment [Line Items]
Summary of Investments in Debt and Equity Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value NDTF Cash and cash equivalents $ — $ — $ 27 $ — $ — $ 13 Equity securities 351 26 430 260 11 403 Corporate debt securities — — — — 1 54 Municipal bonds — — — — — 1 U.S. government bonds 1 — 275 3 1 186 Other debt securities — — — — — 2 Total NDTF Investments (a) $ 352 $ 26 $ 732 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 1 Municipal bonds 3 — 51 — — 47 Total Other Investments $ 3 $ — $ 55 $ — $ — $ 48 Total Investments $ 355 $ 26 $ 787 $ 263 $ 13 $ 707 (a) During the year ended December 31, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 277 Due after one through five years 9 Due after five through 10 years 7 Due after 10 years 33 Total $ 326
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the years ended December 31, 2019 , and 2018 , and from sales of AFS securities for the year ended December 31, 2017 , were as follows. Years Ended December 31, (in millions) 2019 2018 FV-NI: Realized gains $ 21 $ 11 Realized losses 11 5 AFS: Realized gains 29 1 Realized losses 24 5 Year Ended December 31, (in millions) 2017 Realized gains $ 11 Realized losses 8
Duke Energy Indiana
Investment [Line Items]
Summary of Investments in Debt and Equity Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are measured at FV-NI and debt investments are classified as AFS. December 31, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses Fair Value Gains Losses Fair Value Investments Equity securities $ 43 $ — $ 81 $ 29 $ — $ 67 Corporate debt securities — — 6 — — 8 Municipal bonds 1 — 36 — 1 33 U.S. government bonds — — 2 — — — Total Investments $ 44 $ — $ 125 $ 29 $ 1 $ 108
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2019 Due in one year or less $ 4 Due after one through five years 16 Due after five through 10 years 7 Due after 10 years 17 Total $ 44

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 15 . See Note 16 for additional information related to investments by major security type for the Duke Energy Registrants. December 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 5,684 $ 5,633 $ — $ — $ 51 NDTF debt securities 2,469 826 1,643 — — Other equity securities 122 122 — — — Other debt securities 310 91 219 — — Derivative assets 25 3 7 15 — Total assets 8,610 6,675 1,869 15 51 NDTF equity security contracts (23 ) — (23 ) — — Derivative liabilities (277 ) (15 ) (145 ) (117 ) — Net assets (liabilities) $ 8,310 $ 6,660 $ 1,701 $ (102 ) $ 51 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 4,475 $ 4,410 $ — $ — $ 65 NDTF debt securities 2,231 576 1,655 — — Other equity securities 99 99 — — — Other debt securities 270 67 203 — — Derivative assets 57 4 25 28 — Total assets 7,132 5,156 1,883 28 65 Derivative liabilities (242 ) (11 ) (90 ) (141 ) — Net assets (liabilities) $ 6,890 $ 5,145 $ 1,793 $ (113 ) $ 65
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. December 31, 2019 December 31, 2018 (in millions) Derivatives (net) Derivatives (net) Balance at beginning of period $ (113 ) $ (114 ) Purchases, sales, issuances and settlements: Purchases 37 57 Settlements (44 ) (57 ) Total gains included on the Consolidated Balance Sheet 18 1 Balance at end of period $ (102 ) $ (113 )
Quantitative Information Table - Level 3	The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. December 31, 2019 Weighted Fair Value Average Investment Type (in millions) Valuation Technique Unobservable Input Range Range Duke Energy Ohio FTRs $ 4 RTO auction pricing FTR price – per MWh $ 0.59 – $ 3.47 $ 2.07 Duke Energy Indiana FTRs 11 RTO auction pricing FTR price – per MWh (0.66 ) – 9.24 1.15 Piedmont Natural gas contracts (117 ) Discounted cash flow Forward natural gas curves – price per MMBtu 1.59 – 2.46 1.91 Duke Energy Total Level 3 derivatives $ (102 ) December 31, 2018 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 6 RTO auction pricing FTR price – per MWh $ 1.19 – $ 4.59 Duke Energy Indiana FTRs 22 RTO auction pricing FTR price – per MWh (2.07 ) – 8.27 Piedmont Natural gas contracts (141 ) Discounted cash flow Forward natural gas curves – price per MMBtu 1.87 – 2.95 Duke Energy Total Level 3 derivatives $ (113 )
Schedule of Long-term debt Fair Value	The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. December 31, 2019 December 31, 2018 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy (a) $ 58,126 $ 63,062 $ 54,529 $ 54,534 Duke Energy Carolinas 11,900 13,516 10,939 11,471 Progress Energy 19,634 22,291 18,911 19,885 Duke Energy Progress 9,058 9,934 8,204 8,300 Duke Energy Florida 7,987 9,131 7,321 7,742 Duke Energy Ohio 2,619 2,964 2,165 2,239 Duke Energy Indiana 4,057 4,800 3,782 4,158 Piedmont 2,384 2,642 2,138 2,180 (a) Book value of long-term debt includes $1.5 billion as of December 31, 2019 , and $1.6 billion as of December 31, 2018 , of unamortized debt discount and premium, net in purchase accounting adjustments related to the mergers with Progress Energy and Piedmont that are excluded from fair value of long-term debt.
Duke Energy Carolinas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 3,154 $ 3,103 $ — $ 51 NDTF debt securities 1,193 227 966 — Total assets 4,347 3,330 966 51 Derivative liabilities (49 ) — (49 ) — Net assets $ 4,298 $ 3,330 $ 917 $ 51 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 2,484 $ 2,419 $ — $ 65 NDTF debt securities 1,069 149 920 — Derivative assets 3 — 3 — Total assets 3,556 2,568 923 65 Derivative liabilities (33 ) — (33 ) — Net assets $ 3,523 $ 2,568 $ 890 $ 65
Progress Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,530 $ 2,530 $ — $ 1,991 $ 1,991 $ — NDTF debt securities 1,276 599 677 1,162 427 735 Other debt securities 100 49 51 64 17 47 Derivative assets 7 — 7 4 — 4 Total assets 3,913 3,178 735 3,221 2,435 786 NDTF equity security contracts (23 ) — (23 ) — — — Derivative liabilities (65 ) — (65 ) (44 ) — (44 ) Net assets $ 3,825 $ 3,178 $ 647 $ 3,177 $ 2,435 $ 742
Duke Energy Progress
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,077 $ 2,077 $ — $ 1,588 $ 1,588 $ — NDTF debt securities 974 297 677 906 294 612 Other debt securities 2 2 — 6 6 — Derivative assets — — — 4 — 4 Total assets 3,053 2,376 677 2,504 1,888 616 Derivative liabilities (49 ) — (49 ) (27 ) — (27 ) Net assets $ 3,004 $ 2,376 $ 628 $ 2,477 $ 1,888 $ 589
Duke Energy Florida
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 453 $ 453 $ — $ 403 $ 403 $ — NDTF debt securities 302 302 — 256 133 123 Other debt securities 55 4 51 48 1 47 Derivative assets 7 — 7 — — — Total assets 817 759 58 707 537 170 NDTF equity security contracts (23 ) — (23 ) — — — Derivative liabilities (1 ) — (1 ) (9 ) — (9 ) Net assets $ 793 $ 759 $ 34 $ 698 $ 537 $ 161
Duke Energy Indiana
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Other equity securities $ 81 $ 81 $ — $ — $ 67 $ 67 $ — $ — Other debt securities 44 — 44 — 41 — 41 — Derivative assets 13 2 — 11 23 1 — 22 Total assets 138 83 44 11 131 68 41 22 Derivative liabilities (1 ) (1 ) — — — — — — Total assets $ 137 $ 82 $ 44 $ 11 $ 131 $ 68 $ 41 $ 22
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2019 2018 Balance at beginning of period $ 22 $ 27 Purchases, sales, issuances and settlements: Purchases 28 50 Settlements (36 ) (53 ) Total losses included on the Consolidated Balance Sheet (3 ) (2 ) Balance at end of period $ 11 $ 22
Piedmont
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. December 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 3 Total Fair Value Level 1 Level 3 Derivative assets $ 1 $ 1 $ — $ 3 $ 3 $ — Derivative liabilities (117 ) — (117 ) (141 ) — (141 ) Net (liabilities) assets $ (116 ) $ 1 $ (117 ) $ (138 ) $ 3 $ (141 )
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2019 2018 Balance at beginning of period $ (141 ) $ (142 ) Total gains and settlements 24 1 Balance at end of period $ (117 ) $ (141 )

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2019
VIE
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The following table summarizes the amounts and expiration dates of the credit facilities and associated restricted receivables described above. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida (in millions) CRC DERF DEPR DEFR Expiration date February 2023 December 2022 February 2021 April 2021 Credit facility amount $ 350 $ 475 $ 325 $ 250 Amounts borrowed at December 31, 2019 350 474 325 250 Amounts borrowed at December 31, 2018 325 450 300 225 Restricted Receivables at December 31, 2019 522 642 489 336 Restricted Receivables at December 31, 2018 564 699 547 357
VIE | DEFPF
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The following table summarizes the impact of DEFPF on Duke Energy Florida's Consolidated Balance Sheets. December 31, (in millions) 2019 2018 Receivables of VIEs $ 5 $ 5 Regulatory Assets: Current 52 52 Current Assets: Other 39 39 Other Noncurrent Assets: Regulatory assets 989 1,041 Current Liabilities: Other 10 10 Current maturities of long-term debt 54 53 Long-Term Debt 1,057 1,111
VIE | Commercial Renewables
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The table below presents material balances reported on Duke Energy's Consolidated Balance Sheets related to Commercial Renewables VIEs. December 31, (in millions) 2019 2018 Current Assets: Other $ 203 $ 123 Property, Plant and Equipment: Cost 5,747 4,007 Accumulated depreciation and amortization (1,041 ) (698 ) Other Noncurrent Assets: Other 106 261 Current maturities of long-term debt 162 174 Long-Term Debt 1,541 1,587 Other Noncurrent Liabilities: AROs 127 106 Other Noncurrent Liabilities: Other 228 212
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The following tables summarize the impact of non-consolidated VIEs on the Consolidated Balance Sheets. December 31, 2019 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs (a) Total Ohio Indiana Receivables from affiliated companies $ — $ (1 ) $ — $ (1 ) $ 64 $ 77 Investments in equity method unconsolidated affiliates 1,179 300 — 1,479 — — Total assets $ 1,179 $ 299 $ — $ 1,478 $ 64 $ 77 Taxes accrued (1 ) — — (1 ) — — Other current liabilities — — 4 4 — — Deferred income taxes 59 — — 59 — — Other noncurrent liabilities — — 11 11 — — Total liabilities $ 58 $ — $ 15 $ 73 $ — $ — Net assets (liabilities) $ 1,121 $ 299 $ (15 ) $ 1,405 $ 64 $ 77 (a) Duke Energy holds a 50% equity interest in Pioneer. As of December 31, 2018, Pioneer was considered a VIE due to having insufficient equity to finance its own activities without subordinated financial support. In October 2019, Pioneer closed on a private placement debt offering that gave Pioneer sufficient equity to finance its own activities and, therefore, is no longer considered a VIE. Duke Energy's investment in Pioneer was $57 million at December 31, 2019. December 31, 2018 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 93 $ 118 Investments in equity method unconsolidated affiliates 822 190 48 1,060 — — Total assets $ 822 $ 190 $ 48 $ 1,060 $ 93 $ 118 Taxes accrued (1 ) — — (1 ) — — Other current liabilities — — 4 4 — — Deferred income taxes 21 — — 21 — — Other noncurrent liabilities — — 12 12 — — Total liabilities $ 20 $ — $ 16 $ 36 $ — $ — Net assets $ 802 $ 190 $ 32 $ 1,024 $ 93 $ 118
VIE, Not Primary Beneficiary | Pipeline Investments
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The table below presents Duke Energy's ownership interest and investment balances in these joint ventures. VIE Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest 2019 2018 ACP (a) 47 % $ 1,179 $ 797 Constitution (b) 24 % — 25 Total $ 1,179 $ 822 (a) Duke Energy evaluated this investment for impairment as of December 31, 2019, and 2018, and determined that fair value approximated carrying value and therefore no impairment was necessary. (b) During the years ended December 31, 2019, and 2018, Duke Energy recorded an OTTI of $25 million and $55 million , respectively, related to Constitution within Equity in earnings of unconsolidated affiliates on Duke Energy's Consolidated Statements of Income. The current year charge resulted in the full write-down of Duke Energy's investment in Constitution. See Notes 4 and 13 for additional information.
VIE, Not Primary Beneficiary | CRC
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2019 2018 2019 2018 Anticipated credit loss ratio 0.6 % 0.5 % 0.3 % 0.3 % Discount rate 3.3 % 3.0 % 3.3 % 3.0 % Receivable turnover rate 13.4 % 13.5 % 11.5 % 11.0 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana December 31, December 31, (in millions) 2019 2018 2019 2018 Receivables sold $ 253 $ 269 $ 307 $ 336 Less: Retained interests 64 93 77 118 Net receivables sold $ 189 $ 176 $ 230 $ 218 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Years Ended December 31, Years Ended December 31, (in millions) 2019 2018 2017 2019 2018 2017 Sales Receivables sold $ 1,979 $ 1,987 $ 1,879 $ 2,837 $ 2,842 $ 2,711 Loss recognized on sale 14 13 10 17 16 12 Cash flows Cash proceeds from receivables sold 1,993 1,967 1,865 2,860 2,815 2,694 Collection fees received 1 1 1 1 1 1 Return received on retained interests 6 6 3 9 9 7

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	Estimated remaining performance obligations are as follows: Remaining Performance Obligations (in millions) 2020 2021 2022 2023 2024 Thereafter Total Piedmont $ 69 $ 64 $ 64 $ 61 $ 58 $ 372 $ 688 Remaining Performance Obligations (in millions) 2020 2021 2022 2023 2024 Thereafter Total Progress Energy $ 121 $ 92 $ 87 $ 44 $ 45 $ 58 $ 447 Duke Energy Progress 8 8 8 8 8 — 40 Duke Energy Florida 113 84 79 36 37 58 407 Duke Energy Indiana 10 5 — — — — 15
Disaggregation of Revenue	Year Ended December 31, 2018 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 9,587 $ 2,981 $ 4,785 $ 2,019 $ 2,766 $ 743 $ 1,076 $ — General 6,127 2,119 2,809 1,280 1,529 422 778 — Industrial 2,974 1,180 904 642 262 131 760 — Wholesale 2,324 508 1,462 1,303 159 57 298 — Other revenues 717 320 502 320 182 73 91 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 21,729 $ 7,108 $ 10,462 $ 5,564 $ 4,898 $ 1,426 $ 3,003 $ — Gas Utilities and Infrastructure Residential $ 1,000 $ — $ — $ — $ — $ 331 $ — $ 669 Commercial 514 — — — — 135 — 378 Industrial 147 — — — — 18 — 128 Power Generation — — — — — — — 54 Other revenues 139 — — — — 19 — 120 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,800 $ — $ — $ — $ — $ 503 $ — $ 1,349 Commercial Renewables Revenue from contracts with customers $ 209 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 19 $ — $ — $ — $ — $ 1 $ — $ — Total revenue from contracts with customers $ 23,757 $ 7,108 $ 10,462 $ 5,564 $ 4,898 $ 1,930 $ 3,003 $ 1,349 Other revenue sources (a) $ 764 $ 192 $ 266 $ 135 $ 123 $ 27 $ 56 $ 26 Total revenues $ 24,521 $ 7,300 $ 10,728 $ 5,699 $ 5,021 $ 1,957 $ 3,059 $ 1,375 (a) Other revenue sources include revenues from leases, derivatives and alternative revenue programs that are not considered revenues from contracts with customers. Alternative revenue programs in certain jurisdictions include regulatory mechanisms that periodically adjust for over or under collection of related revenues. Year Ended December 31, 2019 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 9,863 $ 3,044 $ 4,998 $ 2,144 $ 2,854 $ 733 $ 1,087 $ — General 6,431 2,244 2,935 1,368 1,567 451 802 — Industrial 3,071 1,215 934 675 259 147 774 — Wholesale 2,212 462 1,468 1,281 187 46 235 — Other revenues 770 276 548 317 231 80 89 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 22,347 $ 7,241 $ 10,883 $ 5,785 $ 5,098 $ 1,457 $ 2,987 $ — Gas Utilities and Infrastructure Residential $ 976 $ — $ — $ — $ — $ 315 $ — $ 661 Commercial 508 — — — — 130 — 378 Industrial 141 — — — — 19 — 122 Power Generation — — — — — — — 51 Other revenues 129 — — — — 19 — 110 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,754 $ — $ — $ — $ — $ 483 $ — $ 1,322 Commercial Renewables Revenue from contracts with customers $ 223 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 24 $ — $ — $ — $ — $ — $ — $ — Total revenue from contracts with customers $ 24,348 $ 7,241 $ 10,883 $ 5,785 $ 5,098 $ 1,940 $ 2,987 $ 1,322 Other revenue sources (a) $ 731 $ 154 $ 319 $ 172 $ 133 $ — $ 17 $ 59 Total revenues $ 25,079 $ 7,395 $ 11,202 $ 5,957 $ 5,231 $ 1,940 $ 3,004 $ 1,381 (a) Other revenue sources include revenues from leases, derivatives and alternative revenue programs that are not considered revenues from contracts with customers. Alternative revenue programs in certain jurisdictions include regulatory mechanisms that periodically adjust for over or under collection of related revenues.
Schedule Of Unbilled Revenues With Restricted Receivables	Unbilled revenues are included within Receivables and Receivables of VIEs on the Consolidated Balance Sheets as shown in the following table. December 31, (in millions) 2019 2018 Duke Energy $ 843 $ 896 Duke Energy Carolinas 298 313 Progress Energy 217 244 Duke Energy Progress 122 148 Duke Energy Florida 95 96 Duke Energy Ohio 1 2 Duke Energy Indiana 16 23 Piedmont 78 73 December 31, (in millions) 2019 2018 Duke Energy Ohio $ 82 $ 86 Duke Energy Indiana 115 128

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule Of Earnings Per Share	The following table presents Duke Energy’s basic and diluted EPS calculations, the weighted average number of common shares outstanding and common and preferred share dividends declared. Years Ended December 31, (in millions, except per share amounts) 2019 2018 2017 Income from continuing operations available to Duke Energy common stockholders excluding impact of participating securities and including accumulated preferred stock dividends $ 3,694 $ 2,642 $ 3,059 Weighted average common shares outstanding – basic and diluted 729 708 700 EPS from continuing operations available to Duke Energy common stockholders Basic and diluted $ 5.07 $ 3.73 $ 4.37 Potentially dilutive items excluded from the calculation (a) 2 2 2 Dividends declared per common share $ 3.75 $ 3.64 $ 3.49 Dividends declared on Series A preferred stock per depositary share $ 1.03 $ — $ — (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met.

Severance (Tables)

Severance (Tables)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Schedule of Severance Expense	by the Duke Energy Registrants within Operation, maintenance and other on the Consolidated Statements of Operations. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Year Ended December 31, 2019 $ 16 $ 8 $ 6 $ 3 $ 3 $ — $ 1 $ 1 Year Ended December 31, 2018 187 102 69 52 17 6 7 2 Year Ended December 31, 2017 15 2 2 1 1 — 1 9
Schedule of Severance Liability	The table below presents the severance liability for past and ongoing severance plans including the plans described above. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at December 31, 2018 $ 205 $ 100 $ 51 $ 41 $ 9 $ 2 $ 2 $ — Provision/Adjustments 24 4 11 2 10 1 1 — Cash Reductions (188 ) (93 ) (49 ) (37 ) (12 ) (2 ) (1 ) — Balance at December 31, 2019 $ 41 $ 11 $ 13 $ 6 $ 7 $ 1 $ 2 $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule Of Total Stock-Based Compensation Expense, net of tax	The following table summarizes the total expense recognized by the Duke Energy Registrants, net of tax, for stock-based compensation. Years Ended December 31, (in millions) 2019 2018 2017 Duke Energy $ 65 $ 56 $ 43 Duke Energy Carolinas 24 20 15 Progress Energy 24 21 16 Duke Energy Progress 15 13 10 Duke Energy Florida 9 8 6 Duke Energy Ohio 5 4 3 Duke Energy Indiana 6 5 4 Piedmont 3 3 3
Schedule Of Stock-Based Compensation Expense	Duke Energy's pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table. Years Ended December 31, (in millions) 2019 2018 2017 RSU awards $ 44 $ 43 $ 41 Performance awards 45 35 27 Pretax stock-based compensation cost $ 89 $ 78 $ 68 Stock-based compensation costs capitalized 5 5 4 Stock-based compensation expense $ 84 $ 73 $ 64 Tax benefit associated with stock-based compensation expense $ 19 $ 17 $ 25
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	The following table includes information related to RSU awards. Years Ended December 31, 2019 2018 2017 Shares granted (in thousands) 571 649 583 Fair value (in millions) $ 51 $ 49 $ 47 The following table summarizes information about RSU awards outstanding. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2018 1,153 $ 77 Granted 571 89 Vested (631 ) 77 Forfeited (83 ) 82 Outstanding at December 31, 2019 1,010 83 RSU awards expected to vest 951 83
Schedule of Performance Awards	The following table includes information related to stock-based performance awards. Years Ended December 31, 2019 2018 2017 Shares granted assuming target performance (in thousands) 320 372 461 Fair value (in millions) $ 27 $ 27 $ 37
Schedule of Nonvested Performance-based Units Activity	The following table summarizes information about stock-based performance awards outstanding and assumes payout at the target level. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2018 1,117 $ 77 Granted 320 86 Vested (310 ) 75 Forfeited (18 ) 81 Outstanding at December 31, 2019 1,109 80 Stock-based performance awards expected to vest 1,080 80

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Contributions	Duke Energy’s policy is to fund amounts on an actuarial basis to provide assets sufficient to meet benefit payments to be paid to plan participants. Duke Energy does not anticipate making any contributions in 2020. The following table includes information related to the Duke Energy Registrants’ contributions to its qualified defined benefit pension plans. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Contributions Made: 2019 $ 77 $ 7 $ 57 $ 4 $ 53 $ 2 $ 2 $ 1 2018 141 46 45 25 20 — 8 — 2017 19 — — — — 4 — 11
Fair Value and Allocation of Plan Assets	The following tables provide the fair value measurement amounts for the Duke Energy Master Retirement Trust qualified pension and other post-retirement assets. December 31, 2019 Total Fair Not (in millions) Value Level 1 Level 2 Level 3 Categorized (b) Equity securities $ 2,730 $ 2,712 $ — $ — $ 18 Corporate debt securities 3,999 — 3,999 — — Short-term investment funds 545 455 90 — — Partnership interests 104 — — — 104 Hedge funds 206 — — — 206 Real estate limited partnerships — — — — — U.S. government securities 1,231 — 1,231 — — Guaranteed investment contracts 11 — — 11 — Governments bonds – foreign 78 — 78 — — Cash 75 75 — — — Net pending transactions and other investments 46 (43 ) 89 — — Total assets (a) $ 9,025 $ 3,199 $ 5,487 $ 11 $ 328 (a) Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio, Duke Energy Indiana, and Piedmont were allocated approximately 26% , 31% , 15% , 17% , 5% , 7% , and 4% , respectively, of the Duke Energy Master Retirement Trust at December 31, 2019 . Accordingly, all amounts included in the table above are allocable to the Subsidiary Registrants using these percentages. (b) Certain investments that are measured at fair value using the net asset value per share practical expedient have not been categorized in the fair value hierarchy. December 31, 2018 Total Fair Not (in millions) Value Level 1 Level 2 Level 3 Categorized (b) Equity securities $ 2,373 $ 1,751 $ — $ — $ 622 Corporate debt securities 4,054 — 4,054 — — Short-term investment funds 363 279 84 — — Partnership interests 120 — — — 120 Hedge funds 226 — — — 226 Real estate limited partnerships 144 — — — 144 U.S. government securities 961 — 961 — — Guaranteed investment contracts 27 — — 27 — Governments bonds – foreign 30 — 30 — — Cash 28 28 — — — Net pending transactions and other investments (2 ) (6 ) 4 — — Total assets (a) $ 8,324 $ 2,052 $ 5,133 $ 27 $ 1,112 (a) Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio, Duke Energy Indiana, and Piedmont were allocated approximately 27% , 31% , 15% , 16% , 5% , 7% , and 4% , respectively, of the Duke Energy Master Retirement Trust and Piedmont's Pension assets at December 31, 2018 . Accordingly, all amounts included in the table above are allocable to the Subsidiary Registrants using these percentages. (b) Certain investments that are measured at fair value using the net asset value per share practical expedient have not been categorized in the fair value hierarchy. The following tables provide the fair value measurement amounts for VEBA trust assets. December 31, 2019 Total Fair (in millions) Value Level 2 Cash and cash equivalents $ 9 $ 9 Real estate 1 1 Equity securities 22 22 Debt securities 18 18 Total assets $ 50 $ 50 December 31, 2018 Total Fair (in millions) Value Level 2 Cash and cash equivalents $ 3 $ 3 Real estate 1 1 Equity securities 25 25 Debt securities 20 20 Total assets $ 49 $ 49 The following table includes the target asset allocations by asset class at December 31, 2019 , and the actual asset allocations for the Duke Energy Master Retirement Trust. Actual Allocation at Target December 31, Allocation 2019 2018 U.S. equity securities — % — % 11 % Global equity securities 28 % 27 % 18 % Global private equity securities 1 % 1 % 2 % Debt securities 58 % 57 % 63 % Return seeking debt securities 4 % 5 % — % Hedge funds 3 % 3 % 2 % Real estate and cash 6 % 7 % 2 % Other global securities — % — % 2 % Total 100 % 100 % 100 % The following table presents target and actual asset allocations for the VEBA trusts at December 31, 2019 . Actual Allocation at Target December 31, Allocation 2019 2018 U.S. equity securities 33 % 35 % 43 % Non-U.S. equity securities 7 % 9 % 8 % Real estate 2 % 2 % 2 % Debt securities 45 % 37 % 40 % Cash 13 % 17 % 7 % Total 100 % 100 % 100 %
Master Trust Level 3 Rollforward	The following table provides a reconciliation of beginning and ending balances of Duke Energy Master Retirement Trust qualified pension and other post-retirement assets at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3). (in millions) 2019 2018 Balance at January 1 $ 27 $ 28 Sales (18 ) (1 ) Total gains and other, net 2 — Transfer of Level 3 assets to other classifications — — Balance at December 31 $ 11 $ 27
Employee Savings Plan Matching Contributions	The following table includes pretax employer matching contributions made by Duke Energy and expensed by the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Years ended December 31, 2019 $ 214 $ 66 $ 58 $ 38 $ 20 $ 5 $ 11 $ 13 2018 213 68 58 40 19 4 10 12 2017 179 61 53 37 16 3 9 7
Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	Components of Net Periodic Pension Costs Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 158 $ 49 $ 46 $ 26 $ 20 $ 4 $ 9 $ 5 Interest cost on projected benefit obligation 317 75 100 45 54 18 26 10 Expected return on plan assets (567 ) (147 ) (178 ) (88 ) (89 ) (28 ) (43 ) (22 ) Amortization of actuarial loss 108 24 39 15 24 4 8 8 Amortization of prior service credit (32 ) (8 ) (3 ) (2 ) (1 ) — (2 ) (9 ) Amortization of settlement charges 6 2 1 1 — 2 — — Net periodic pension costs (a)(b) $ (10 ) $ (5 ) $ 5 $ (3 ) $ 8 $ — $ (2 ) $ (8 ) Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 182 $ 58 $ 51 $ 29 $ 22 $ 5 $ 11 $ 7 Interest cost on projected benefit obligation 299 72 94 43 50 17 23 11 Expected return on plan assets (559 ) (147 ) (178 ) (85 ) (91 ) (28 ) (42 ) (22 ) Amortization of actuarial loss 132 29 44 21 23 5 10 11 Amortization of prior service credit (32 ) (8 ) (3 ) (2 ) (1 ) — (2 ) (10 ) Net periodic pension costs (a)(b) $ 22 $ 4 $ 8 $ 6 $ 3 $ (1 ) $ — $ (3 ) Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 159 $ 48 $ 45 $ 26 $ 19 $ 4 $ 9 $ 10 Interest cost on projected benefit obligation 328 79 100 47 53 18 26 14 Expected return on plan assets (545 ) (142 ) (167 ) (82 ) (85 ) (27 ) (42 ) (24 ) Amortization of actuarial loss 146 31 52 23 29 5 12 11 Amortization of prior service credit (24 ) (8 ) (3 ) (2 ) (1 ) (1 ) (2 ) (2 ) Settlement charge 12 — — — — — — 12 Other 8 2 2 1 1 — 1 1 Net periodic pension costs (a)(b) $ 84 $ 10 $ 29 $ 13 $ 16 $ (1 ) $ 4 $ 22 (a) Duke Energy amounts exclude $4 million , $5 million and $7 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $2 million , $2 million and $3 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006.
Amounts Recognized in AOCI and Regulatory Assets and Liabilities	Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase (decrease) $ (212 ) $ (156 ) $ (79 ) $ (59 ) $ (20 ) $ 12 $ 22 $ — Accumulated other comprehensive loss (income) Deferred income tax expense (benefit) $ 20 — 1 — (1 ) — — — Amortization of prior year service credit 1 — — — — — — — Amortization of prior year actuarial losses (15 ) — (2 ) — 3 — — — Net amount recognized in accumulated other comprehensive income $ 6 $ — $ (1 ) $ — $ 2 $ — $ — $ — Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase $ 298 $ 170 $ 40 $ 31 $ 9 $ 10 $ 30 $ 8 Accumulated other comprehensive (income) loss Deferred income tax expense $ (2 ) $ — $ 1 $ — $ — $ — $ — $ — Prior year service credit arising during the year 1 — — — — — — — Amortization of prior year actuarial losses 10 — (4 ) — — — — — Net amount recognized in accumulated other comprehensive income $ 9 $ — $ (3 ) $ — $ — $ — $ — $ —
Reconciliation of Funded Status to Net Amount Recognized	Reconciliation of Funded Status to Net Amount Recognized Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Obligation at prior measurement date $ 7,869 $ 1,954 $ 2,433 $ 1,125 $ 1,295 $ 435 $ 618 $ 264 Service cost 150 47 43 25 18 4 8 5 Interest cost 317 75 100 45 54 18 26 10 Actuarial loss 716 101 223 87 135 54 87 33 Transfers — 11 — — — — — — Benefits paid (731 ) (265 ) (191 ) (112 ) (78 ) (30 ) (46 ) (20 ) Obligation at measurement date $ 8,321 $ 1,923 $ 2,608 $ 1,170 $ 1,424 $ 481 $ 693 $ 292 Accumulated Benefit Obligation at measurement date $ 8,262 $ 1,923 $ 2,578 $ 1,170 $ 1,392 $ 471 $ 686 $ 292 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 8,233 $ 2,168 $ 2,606 $ 1,268 $ 1,322 $ 405 $ 611 $ 305 Employer contributions 77 7 57 4 53 2 2 1 Actual return on plan assets 1,331 342 426 204 218 66 100 49 Benefits paid (731 ) (265 ) (191 ) (112 ) (78 ) (30 ) (46 ) (20 ) Transfers — 11 — — — — — — Plan assets at measurement date $ 8,910 $ 2,263 $ 2,898 $ 1,364 $ 1,515 $ 443 $ 667 $ 335 Funded status of plan $ 589 $ 340 $ 290 $ 194 $ 91 $ (38 ) $ (26 ) $ 43 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Obligation at prior measurement date $ 8,448 $ 2,029 $ 2,637 $ 1,211 $ 1,410 $ 479 $ 669 $ 313 Service cost 174 56 49 28 21 5 10 7 Interest cost 299 72 94 43 50 17 23 11 Actuarial gain (485 ) (44 ) (204 ) (87 ) (114 ) (29 ) (29 ) (18 ) Transfers — — — — — — — (16 ) Benefits paid (567 ) (159 ) (143 ) (70 ) (72 ) (37 ) (55 ) (33 ) Obligation at measurement date $ 7,869 $ 1,954 $ 2,433 $ 1,125 $ 1,295 $ 435 $ 618 $ 264 Accumulated Benefit Obligation at measurement date $ 7,818 $ 1,954 $ 2,404 $ 1,125 $ 1,265 $ 425 $ 614 $ 264 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 9,003 $ 2,372 $ 2,814 $ 1,366 $ 1,429 $ 458 $ 684 $ 368 Employer contributions 141 46 45 25 20 — 8 — Actual return on plan assets (344 ) (91 ) (110 ) (53 ) (55 ) (16 ) (26 ) (14 ) Benefits paid (567 ) (159 ) (143 ) (70 ) (72 ) (37 ) (55 ) (33 ) Transfers — — — — — — — (16 ) Plan assets at measurement date $ 8,233 $ 2,168 $ 2,606 $ 1,268 $ 1,322 $ 405 $ 611 $ 305 Funded status of plan $ 364 $ 214 $ 173 $ 143 $ 27 $ (30 ) $ (7 ) $ 41
Amounts Recognized in the Consolidated Balance Sheet	Amounts Recognized in the Consolidated Balance Sheets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Prefunded pension (a) $ 621 $ 340 $ 322 $ 194 $ 123 $ 38 $ 57 $ 43 Noncurrent pension liability (b) $ 32 $ — $ 32 $ — $ 32 $ 76 $ 83 $ — Net asset (liability) recognized $ 589 $ 340 $ 290 $ 194 $ 91 $ (38 ) $ (26 ) $ 43 Regulatory assets $ 1,972 $ 420 $ 717 $ 313 $ 404 $ 112 $ 204 $ 81 Accumulated other comprehensive (income) loss Deferred income tax benefit $ (23 ) $ — $ (1 ) $ — $ (1 ) $ — $ — $ — Prior service credit (3 ) — — — — — — — Net actuarial loss 111 — 3 — 3 — — — Net amounts recognized in accumulated other comprehensive loss $ 85 $ — $ 2 $ — $ 2 $ — $ — $ — Amounts to be recognized in net periodic pension costs in the next year Unrecognized net actuarial loss $ 135 $ 29 $ 43 $ 19 $ 24 $ 7 $ 10 $ 9 Unrecognized prior service credit (32 ) (8 ) (3 ) (2 ) (1 ) (1 ) (2 ) (9 ) December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Prefunded pension (a) $ 433 $ 214 $ 242 $ 143 $ 96 $ 24 $ 39 $ 41 Noncurrent pension liability (b) $ 69 $ — $ 69 $ — $ 69 $ 54 $ 46 $ — Net asset recognized $ 364 $ 214 $ 173 $ 143 $ 27 $ (30 ) $ (7 ) $ 41 Regulatory assets $ 2,184 $ 576 $ 796 $ 372 $ 424 $ 100 $ 182 $ 81 Accumulated other comprehensive (income) loss Deferred income tax benefit $ (43 ) $ — $ (2 ) $ — $ — $ — $ — $ — Prior service credit (4 ) — — — — — — — Net actuarial loss 126 — 5 — — — — — Net amounts recognized in accumulated other comprehensive loss $ 79 $ — $ 3 $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension costs in the next year Unrecognized net actuarial loss $ 97 $ 22 $ 37 $ 13 $ 24 $ 3 $ 5 $ 7 Unrecognized prior service credit $ (32 ) $ (8 ) $ (3 ) $ (2 ) $ (1 ) $ — $ (2 ) $ (9 ) (a) Included in Other within Other Noncurrent Assets on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets.
Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets	Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets December 31, 2019 Duke Duke Energy Energy (in millions) Ohio Indiana Projected benefit obligation $ 155 $ 260 Accumulated benefit obligation 146 252 Fair value of plan assets 79 177 December 31, 2018 Duke Duke Duke Duke Progress Energy Energy Energy (in millions) Energy Energy Florida Ohio Indiana Projected benefit obligation $ 679 $ 679 $ 679 $ 123 $ 203 Accumulated benefit obligation 651 651 651 115 199 Fair value of plan assets 610 610 610 69 159
Assumptions Used for Pension Benefits Accounting	The following tables present the assumptions or range of assumptions used for pension benefit accounting. December 31, 2019 2018 2017 Benefit Obligations Discount rate 3.30% 4.30% 3.60% Salary increase 3.50 % – 4.00% 3.50 % – 4.00% 3.50 % – 4.00% Net Periodic Benefit Cost Discount rate 4.30% 3.60% 4.10% Salary increase 3.50 % – 4.00% 3.50 % – 4.00% 4.00 % – 4.50% Expected long-term rate of return on plan assets 6.85% 6.50% 6.50 % – 6.75%
Expected Benefit Payments	Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Years ending December 31, 2020 $ 643 $ 167 $ 169 $ 89 $ 79 $ 37 $ 50 $ 28 2021 653 171 178 95 82 37 50 24 2022 649 177 176 92 84 37 49 22 2023 649 174 182 95 86 36 48 21 2024 638 168 184 96 87 35 48 20 2025-2029 2,851 714 871 419 448 156 220 87
Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	Components of Net Periodic Other Post-Retirement Benefit Costs Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 4 $ 1 $ 1 $ — $ 1 $ — $ 1 $ — Interest cost on accumulated post-retirement benefit obligation 30 7 12 7 5 1 3 1 Expected return on plan assets (12 ) (7 ) — — — — — (1 ) Amortization of actuarial loss 4 2 1 — 1 — 4 — Amortization of prior service credit (19 ) (5 ) (8 ) (1 ) (7 ) (1 ) (1 ) (2 ) Net periodic post-retirement benefit costs (a)(b) $ 7 $ (2 ) $ 6 $ 6 $ — $ — $ 7 $ (2 ) Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 6 $ 1 $ 1 $ — $ 1 $ 1 $ 1 $ 1 Interest cost on accumulated post-retirement benefit obligation 28 7 12 6 6 1 3 1 Expected return on plan assets (13 ) (8 ) — — — — — (2 ) Amortization of actuarial loss 6 3 1 1 — — 4 — Amortization of prior service credit (19 ) (5 ) (8 ) (1 ) (7 ) (1 ) (1 ) (2 ) Net periodic post-retirement benefit costs (a)(b) $ 8 $ (2 ) $ 6 $ 6 $ — $ 1 $ 7 $ (2 ) Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 4 $ 1 $ — $ — $ — $ — $ — $ 1 Interest cost on accumulated post-retirement benefit obligation 34 8 13 7 6 1 3 1 Expected return on plan assets (14 ) (8 ) — — — — (1 ) (2 ) Amortization of actuarial loss (gain) 10 (2 ) 21 12 9 (2 ) (1 ) 1 Amortization of prior service credit (115 ) (10 ) (84 ) (54 ) (30 ) — (1 ) — Curtailment credit (c) (30 ) (4 ) (16 ) — (16 ) (2 ) (2 ) — Net periodic post-retirement benefit costs (a)(b) $ (111 ) $ (15 ) $ (66 ) $ (35 ) $ (31 ) $ (3 ) $ (2 ) $ 1 (a) Duke Energy amounts exclude $6 million , $7 million and $7 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $2 million , $2 million and $2 million for the years ended December 2019 , 2018 and 2017 , respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (c) Curtailment credit resulted from a reduction in average future service of plan participants due to a plan amendment.
Amounts Recognized in AOCI and Regulatory Assets and Liabilities	Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase (decrease) $ (127 ) $ — $ (127 ) $ (82 ) $ (45 ) $ — $ (5 ) $ — Regulatory liabilities, net increase (decrease) $ (152 ) $ 1 $ (149 ) $ (93 ) $ (56 ) $ (1 ) $ (4 ) $ 3 Accumulated other comprehensive (income) loss Deferred income tax benefit $ — $ — $ — $ — $ — $ — $ — $ — Amortization of prior year actuarial gain (4 ) — — — — — — — Net amount recognized in accumulated other comprehensive income $ (4 ) $ — $ — $ — $ — $ — $ — $ — Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Regulatory assets, net increase (decrease) $ 137 $ — $ 133 $ 84 $ 49 $ — $ (5 ) $ 4 Regulatory liabilities, net increase (decrease) $ 154 $ (6 ) $ 149 $ 93 $ 56 $ 2 $ 3 $ — Accumulated other comprehensive (income) loss Deferred income tax benefit $ (1 ) $ — $ — $ — $ — $ — $ — $ — Amortization of prior year prior service credit 1 — — — — — — — Net amount recognized in accumulated other comprehensive income $ — $ — $ — $ — $ — $ — $ — $ —
Reconciliation of Funded Status to Net Amount Recognized	Reconciliation of Funded Status to Accrued Other Post-Retirement Benefit Costs Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 728 $ 174 $ 303 $ 166 $ 137 $ 29 $ 67 $ 30 Service cost 4 1 1 — 1 — 1 — Interest cost 30 7 12 7 5 1 3 1 Plan participants' contributions 16 3 6 3 2 1 2 — Actuarial losses 28 9 13 9 5 1 2 — Transfers — — — — — — — — Benefits paid (83 ) (19 ) (32 ) (17 ) (15 ) (3 ) (11 ) (1 ) Accumulated post-retirement benefit obligation at measurement date $ 723 $ 175 $ 303 $ 168 $ 135 $ 29 $ 64 $ 30 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 195 $ 115 $ — $ — $ — $ 8 $ 5 $ 29 Actual return on plan assets 32 20 (1 ) — — 1 — 6 Benefits paid (83 ) (19 ) (32 ) (17 ) (15 ) (3 ) (11 ) (1 ) Employer contributions 60 11 26 13 13 2 9 — Plan participants' contributions 16 3 6 3 2 1 2 — Plan assets at measurement date $ 220 $ 130 $ (1 ) $ (1 ) $ — $ 9 $ 5 $ 34 Funded status of plan $ (503 ) $ (45 ) $ (304 ) $ (169 ) $ (135 ) $ (20 ) $ (59 ) $ 4 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 813 $ 189 $ 342 $ 184 $ 156 $ 30 $ 78 $ 32 Service cost 6 1 1 — 1 1 1 1 Interest cost 28 7 12 6 6 1 3 1 Plan participants' contributions 18 3 6 4 3 1 2 — Actuarial losses (gains) (51 ) (8 ) (23 ) (9 ) (13 ) (2 ) (5 ) (1 ) Transfers — — — — — — — (1 ) Benefits paid (86 ) (18 ) (35 ) (19 ) (16 ) (2 ) (12 ) (2 ) Accumulated post-retirement benefit obligation at measurement date $ 728 $ 174 $ 303 $ 166 $ 137 $ 29 $ 67 $ 30 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 225 $ 133 $ — $ — $ — $ 7 $ 11 $ 31 Actual return on plan assets (8 ) (5 ) — — — — — (1 ) Benefits paid (86 ) (18 ) (35 ) (19 ) (16 ) (2 ) (12 ) (2 ) Employer contributions (reimbursements) 46 2 29 15 13 2 4 1 Plan participants' contributions 18 3 6 4 3 1 2 — Plan assets at measurement date $ 195 $ 115 $ — $ — $ — $ 8 $ 5 $ 29 Funded status of plan $ (533 ) $ (59 ) $ (303 ) $ (166 ) $ (137 ) $ (21 ) $ (62 ) $ (1 )
Amounts Recognized in the Consolidated Balance Sheet	Amounts Recognized in the Consolidated Balance Sheets December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current post-retirement liability (a) $ 9 $ — $ 5 $ 3 $ 2 $ 1 $ — $ — Noncurrent post-retirement liability (b) 494 45 299 166 133 19 59 (4 ) Total accrued post-retirement liability $ 503 $ 45 $ 304 $ 169 $ 135 $ 20 $ 59 $ (4 ) Regulatory assets $ 135 $ — $ 135 $ 82 $ 53 $ — $ 36 $ — Regulatory liabilities $ 149 $ 39 $ — $ — $ — $ 17 $ 63 $ 3 Accumulated other comprehensive (income) loss Deferred income tax expense $ 3 $ — $ — $ — $ — $ — $ — $ — Prior service credit (2 ) — — — — — — — Net actuarial gain (13 ) — — — — — — — Net amounts recognized in accumulated other comprehensive income $ (12 ) $ — $ — $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss $ 5 $ 3 $ 1 $ — $ 1 $ — $ — $ — Unrecognized prior service credit (14 ) (4 ) (3 ) (1 ) (2 ) (1 ) (1 ) (2 ) December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current post-retirement liability (a) $ 8 $ — $ 5 $ 3 $ 2 $ 2 $ — $ — Noncurrent post-retirement liability (b) 525 59 298 163 135 19 62 1 Total accrued post-retirement liability $ 533 $ 59 $ 303 $ 166 $ 137 $ 21 $ 62 $ 1 Regulatory assets $ 262 $ — $ 262 $ 164 $ 98 $ — $ 41 $ — Regulatory liabilities $ 301 $ 38 $ 149 $ 93 $ 56 $ 18 $ 67 $ — Accumulated other comprehensive (income) loss Deferred income tax expense $ 3 $ — $ — $ — $ — $ — $ — $ — Prior service credit (2 ) — — — — — — — Net actuarial gain (9 ) — — — — — — — Net amounts recognized in accumulated other comprehensive income $ (8 ) $ — $ — $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss (gain) $ 4 $ 2 $ 1 $ — $ — $ — $ — $ — Unrecognized prior service credit (19 ) (5 ) (7 ) (1 ) (6 ) (1 ) (1 ) (2 ) (a) Included in Other within Current Liabilities on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets.
Assumptions Used for Pension Benefits Accounting	The following tables present the assumptions used for other post-retirement benefits accounting. December 31, 2019 2018 2017 Benefit Obligations Discount rate 3.30 % 4.30 % 3.60 % Net Periodic Benefit Cost Discount rate 4.30 % 3.60 % 4.10 % Expected long-term rate of return on plan assets 6.85 % 6.50 % 6.50 % Assumed tax rate 23 % 35 % 35 %
Assumed Health Care Cost Trend Rate	Assumed Health Care Cost Trend Rate December 31, 2019 2018 Health care cost trend rate assumed for next year 6.00 % 6.50 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that rate reaches ultimate trend 2026 2024
Sensitivity to Changes in Assumed Health Care Cost Trend Rates	Sensitivity to Changes in Assumed Health Care Cost Trend Rates Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 1-Percentage Point Increase Effect on total service and interest costs $ 1 $ — $ 1 $ 1 $ — $ — $ — $ — Effect on post-retirement benefit obligation 22 5 9 5 4 1 2 1 1-Percentage Point Decrease Effect on total service and interest costs (1 ) — (1 ) (1 ) — — — — Effect on post-retirement benefit obligation (20 ) (5 ) (8 ) (4 ) (4 ) (1 ) (2 ) (1 )
Expected Benefit Payments	Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Years ending December 31, 2020 $ 76 $ 18 $ 29 $ 16 $ 13 $ 4 $ 8 $ 2 2021 70 17 28 15 13 3 7 2 2022 66 16 27 14 12 3 7 2 2023 63 15 25 14 12 3 6 2 2024 59 15 24 13 11 3 6 2 2025-2029 246 60 101 55 46 11 23 11

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Components of Income Tax Expense Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current income taxes Federal $ (299 ) $ 164 $ (173 ) $ (36 ) $ (43 ) $ (41 ) $ (23 ) $ (92 ) State 10 13 (7 ) (3 ) 18 (1 ) 1 (1 ) Foreign 2 — — — — — — — Total current income taxes (287 ) 177 (180 ) (39 ) (25 ) (42 ) (22 ) (93 ) Deferred income taxes Federal 855 175 422 220 153 77 128 133 State (38 ) (37 ) 17 (18 ) 27 5 28 3 Total deferred income taxes (a) 817 138 439 202 180 82 156 136 ITC amortization (11 ) (4 ) (6 ) (6 ) — — — — Income tax expense from continuing operations 519 311 253 157 155 40 134 43 Tax benefit from discontinued operations (2 ) — — — — — — — Total income tax expense included in Consolidated Statements of Operations $ 517 $ 311 $ 253 $ 157 $ 155 $ 40 $ 134 $ 43 (a) Total deferred income taxes includes the generation of tax credit carryforwards of $8 million at Duke Energy Carolinas. In addition, total deferred income taxes includes utilization of NOL carryforwards and tax credit carryforwards of $243 million at Progress Energy, $35 million at Duke Energy Progress, $152 million at Duke Energy Florida, $25 million at Duke Energy Ohio, $60 million at Duke Energy Indiana, $90 million at Piedmont and $775 million at Duke Energy. Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current income taxes Federal $ (647 ) $ (8 ) $ (135 ) $ (71 ) $ (49 ) $ 20 $ 29 $ 67 State (11 ) 6 (5 ) (5 ) (10 ) (1 ) 3 1 Foreign 3 — — — — — — — Total current income taxes (655 ) (2 ) (140 ) (76 ) (59 ) 19 32 68 Deferred income taxes Federal 1,064 299 341 256 115 21 74 (36 ) State 49 11 20 (17 ) 45 3 22 5 Total deferred income taxes (a)(b) 1,113 310 361 239 160 24 96 (31 ) ITC amortization (10 ) (5 ) (3 ) (3 ) — — — — Income tax expense from continuing operations 448 303 218 160 101 43 128 37 Tax benefit from discontinued operations (26 ) — — — — — — — Total income tax expense included in Consolidated Statements of Operations $ 422 $ 303 $ 218 $ 160 $ 101 $ 43 $ 128 $ 37 (a) Includes benefits of NOL carryforwards and tax credit carryforwards of $22 million at Duke Energy Carolinas, $293 million at Progress Energy, $59 million at Duke Energy Progress, $219 million at Duke Energy Florida, $17 million at Duke Energy Ohio, $21 million at Duke Energy Indiana and $39 million at Piedmont. In addition, total deferred income taxes includes utilization of NOL carryforwards and tax credit carryforwards of $18 million at Duke Energy. (b) For the year ended December 31, 2018, the Company has revised the December 31, 2017, estimates of the income tax effects of the Tax Act, in accordance with SAB 118. See the Statutory Rate Reconciliation section below for additional information on the Tax Act's impact on income tax expense. Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current income taxes Federal $ (247 ) $ 221 $ (436 ) $ (95 ) $ (188 ) $ (37 ) $ 128 $ (90 ) State 4 20 (5 ) 2 (11 ) 2 21 (3 ) Foreign 3 — — — — — — — Total current income taxes (240 ) 241 (441 ) (93 ) (199 ) (35 ) 149 (93 ) Deferred income taxes Federal 1,344 381 664 378 194 99 138 147 State 102 35 44 10 51 (4 ) 14 8 Total deferred income taxes (a)(b) 1,446 416 708 388 245 95 152 155 ITC amortization (10 ) (5 ) (3 ) (3 ) — (1 ) — — Income tax expense from continuing operations 1,196 652 264 292 46 59 301 62 Tax benefit from discontinued operations (6 ) — — — — — — — Total income tax expense included in Consolidated Statements of Operations $ 1,190 $ 652 $ 264 $ 292 $ 46 $ 59 $ 301 $ 62 (a) Includes utilization of NOL carryforwards and tax credit carryforwards of $428 million at Duke Energy, $74 million at Progress Energy, $36 million at Duke Energy Florida, $17 million at Duke Energy Ohio, $42 million at Duke Energy Indiana and $79 million at Piedmont. In addition, total deferred income taxes includes benefits of NOL carryforwards and tax credit carryforwards of $10 million at Duke Energy Carolinas and $1 million at Duke Energy Progress. (b) As a result of the Tax Act, Duke Energy's deferred tax assets and liabilities were revalued as of December 31, 2017. See the Statutory Rate Reconciliation section below for additional information on the Tax Act's impact on income tax expense.
Schedule of Income before Income Tax, Domestic and Foreign	Duke Energy Income from Continuing Operations before Income Taxes Years Ended December 31, (in millions) 2019 2018 2017 Domestic (a) $ 4,053 $ 3,018 $ 4,207 Foreign 44 55 59 Income from continuing operations before income taxes $ 4,097 $ 3,073 $ 4,266 (a) Includes a $16 million expense in 2017 related to the Tax Act impact on equity earnings included within Equity in earnings of unconsolidated affiliates on the Consolidated Statement of Operations.
Summary of Effective Tax Rates	The following tables present a reconciliation of income tax expense at the U.S. federal statutory tax rate to the actual tax expense from continuing operations. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Income tax expense, computed at the statutory rate of 21% $ 860 $ 360 $ 332 $ 202 $ 178 $ 59 $ 120 $ 51 State income tax, net of federal income tax effect (22 ) (19 ) 8 (17 ) 35 3 22 2 Amortization of excess deferred income tax (121 ) (29 ) (64 ) (10 ) (54 ) (12 ) (6 ) (10 ) AFUDC equity income (52 ) (9 ) (14 ) (13 ) (1 ) (3 ) (3 ) — AFUDC equity depreciation 34 19 10 5 5 1 4 — Renewable energy PTCs (120 ) — — — — — — — Other tax credits (23 ) (11 ) (9 ) (7 ) (2 ) (1 ) (1 ) (1 ) Tax true up (64 ) (9 ) (8 ) (3 ) (5 ) (7 ) (1 ) — Other items, net 27 9 (2 ) — (1 ) — (1 ) 1 Income tax expense from continuing operations $ 519 $ 311 $ 253 $ 157 $ 155 $ 40 $ 134 $ 43 Effective tax rate 12.7 % 18.1 % 16.0 % 16.3 % 18.3 % 14.3 % 23.5 % 17.6 % Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Income tax expense, computed at the statutory rate of 21% $ 645 $ 288 $ 263 $ 174 $ 137 $ 46 $ 109 $ 35 State income tax, net of federal income tax effect 30 14 13 (17 ) 28 2 20 4 Amortization of excess deferred income tax (61 ) — (55 ) (1 ) (54 ) (3 ) (2 ) — AFUDC equity income (42 ) (15 ) (22 ) (12 ) (10 ) (2 ) (2 ) — AFUDC equity depreciation 31 18 9 5 4 1 4 — Renewable energy PTCs (129 ) — — — — — — — Other tax credits (28 ) (7 ) (13 ) (5 ) (8 ) (1 ) (1 ) (3 ) Tax Act (a) 20 1 25 19 — 2 — — Other items, net (18 ) 4 (2 ) (3 ) 4 (2 ) — 1 Income tax expense from continuing operations $ 448 $ 303 $ 218 $ 160 $ 101 $ 43 $ 128 $ 37 Effective tax rate 14.6 % 22.1 % 17.4 % 19.3 % 15.4 % 19.6 % 24.6 % 22.3 % (a) For the year ended December 31, 2018, the Company revised the December 31, 2017 estimates of the income tax effects of the Tax Act, in accordance with SAB 118. Amounts primarily include but are not limited to items that are excluded for ratemaking purposes related certain wholesale fixed rate contracts, remeasurement of nonregulated net deferred tax liabilities, Federal NOLs, and valuation allowance on foreign tax credits. Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Income tax expense, computed at the statutory rate of 35% $ 1,493 $ 653 $ 536 $ 353 $ 265 $ 88 $ 229 $ 70 State income tax, net of federal income tax effect 69 36 25 8 26 (1 ) 23 3 AFUDC equity income (81 ) (37 ) (32 ) (17 ) (16 ) (4 ) (8 ) — Renewable energy PTCs (132 ) — — — — — — — Tax Act (a) (112 ) 15 (246 ) (40 ) (226 ) (23 ) 55 (12 ) Tax true up (52 ) (24 ) (19 ) (13 ) (7 ) (5 ) (6 ) — Other items, net 11 9 — 1 4 4 8 1 Income tax expense from continuing operations $ 1,196 $ 652 $ 264 $ 292 $ 46 $ 59 $ 301 $ 62 Effective tax rate 28.0 % 34.9 % 17.2 % 29.0 % 6.1 % 23.4 % 46.0 % 30.8 % (a) Amounts primarily include but are not limited to items that are excluded for ratemaking purposes related to abandoned or impaired assets, certain wholesale fixed rate contracts, remeasurement of nonregulated net deferred tax liabilities, Federal NOLs, and valuation allowance on foreign tax credits.
Schedule of Deferred Tax Assets and Liabilities	Net Deferred Income Tax Liability Components December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Deferred credits and other liabilities $ 125 $ 24 $ 25 $ 49 $ — $ 14 $ 5 $ 22 Lease obligations 462 72 193 92 102 5 17 6 Pension, post-retirement and other employee benefits 303 (5 ) 88 38 44 17 27 (3 ) Progress Energy merger purchase accounting adjustments (a) 389 — — — — — — — Tax credits and NOL carryforwards 3,925 262 486 176 253 16 176 19 Regulatory liabilities and deferred credits — — — — — 36 52 42 Investments and other assets — — — — — 10 — 2 Other 97 5 8 3 2 8 1 6 Valuation allowance (587 ) — — — — — — — Total deferred income tax assets 4,714 358 800 358 401 106 278 94 Investments and other assets (1,664 ) (981 ) (577 ) (390 ) (190 ) — (12 ) — Accelerated depreciation rates (10,813 ) (3,254 ) (3,798 ) (1,918 ) (1,913 ) (1,028 ) (1,416 ) (802 ) Regulatory assets and deferred debits, net (1,115 ) (44 ) (887 ) (438 ) (477 ) — — — Total deferred income tax liabilities (13,592 ) (4,279 ) (5,262 ) (2,746 ) (2,580 ) (1,028 ) (1,428 ) (802 ) Net deferred income tax liabilities $ (8,878 ) $ (3,921 ) $ (4,462 ) $ (2,388 ) $ (2,179 ) $ (922 ) $ (1,150 ) $ (708 ) (a) Primarily related to finance lease obligations and debt fair value adjustments. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Deferred credits and other liabilities $ 164 $ 64 $ 35 $ 53 $ — $ 17 $ 6 $ 17 Finance lease obligations 60 26 — — — — 2 — Pension, post-retirement and other employee benefits 347 24 110 47 58 16 24 (1 ) Progress Energy merger purchase accounting adjustments (a) 483 — — — — — — — Tax credits and NOL carryforwards 4,580 257 693 215 363 42 237 110 Regulatory liabilities and deferred credits — — — — — 56 — 48 Investments and other assets — — — — — 18 — 16 Other 25 6 5 5 — 1 (1 ) — Valuation allowance (484 ) — — — — — — — Total deferred income tax assets 5,175 377 843 320 421 150 268 190 Investments and other assets (1,317 ) (795 ) (430 ) (272 ) (163 ) — (5 ) — Accelerated depreciation rates (10,124 ) (3,207 ) (3,369 ) (1,735 ) (1,670 ) (967 ) (1,081 ) (733 ) Regulatory assets and deferred debits, net (1,540 ) (64 ) (985 ) (432 ) (574 ) — (191 ) — Other — — — — — — — (8 ) Total deferred income tax liabilities (12,981 ) (4,066 ) (4,784 ) (2,439 ) (2,407 ) (967 ) (1,277 ) (741 ) Net deferred income tax liabilities $ (7,806 ) $ (3,689 ) $ (3,941 ) $ (2,119 ) $ (1,986 ) $ (817 ) $ (1,009 ) $ (551 ) (a) Primarily related to finance lease obligations and debt fair value adjustments.
Summary of Tax Credit Carryforwards	The following table presents the expiration of tax credits and NOL carryforwards. December 31, 2019 (in millions) Amount Expiration Year General Business Credits $ 1,821 2024 — 2039 AMT credits 286 Refundable by 2021 Federal NOL carryforwards (a) (f) 169 2024 — Indefinite Capital loss carryforward (e) 87 2024 State carryforwards and credits (b) (f) 303 2020 — Indefinite Foreign NOL carryforwards (c) 12 2027 — 2037 Foreign Tax Credits (d) 1,237 2024 — 2027 Charitable contribution carryforwards 10 2020 — 2024 Total tax credits and NOL carryforwards $ 3,925 (a) A valuation allowance of $4 million has been recorded on the Federal NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (b) A valuation allowance of $97 million has been recorded on the state NOL and credit carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (c) A valuation allowance of $12 million has been recorded on the foreign NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (d) A valuation allowance of $387 million has been recorded on the foreign tax credits, as presented in the Net Deferred Income Tax Liability Components table. (e) A valuation allowance of $87 million has been recorded on the Federal capital loss carryforward, as presented in the Net Deferred Income Tax Liability Components table. (f) Indefinite carryforward for Federal NOLs, and NOLs for states that have adopted the Tax Act's NOL provisions, generated in tax years beginning after December 31, 2017. December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Deferred credits and other liabilities $ 164 $ 64 $ 35 $ 53 $ — $ 17 $ 6 $ 17 Finance lease obligations 60 26 — — — — 2 — Pension, post-retirement and other employee benefits 347 24 110 47 58 16 24 (1 ) Progress Energy merger purchase accounting adjustments (a) 483 — — — — — — — Tax credits and NOL carryforwards 4,580 257 693 215 363 42 237 110 Regulatory liabilities and deferred credits — — — — — 56 — 48 Investments and other assets — — — — — 18 — 16 Other 25 6 5 5 — 1 (1 ) — Valuation allowance (484 ) — — — — — — — Total deferred income tax assets 5,175 377 843 320 421 150 268 190 Investments and other assets (1,317 ) (795 ) (430 ) (272 ) (163 ) — (5 ) — Accelerated depreciation rates (10,124 ) (3,207 ) (3,369 ) (1,735 ) (1,670 ) (967 ) (1,081 ) (733 ) Regulatory assets and deferred debits, net (1,540 ) (64 ) (985 ) (432 ) (574 ) — (191 ) — Other — — — — — — — (8 ) Total deferred income tax liabilities (12,981 ) (4,066 ) (4,784 ) (2,439 ) (2,407 ) (967 ) (1,277 ) (741 ) Net deferred income tax liabilities $ (7,806 ) $ (3,689 ) $ (3,941 ) $ (2,119 ) $ (1,986 ) $ (817 ) $ (1,009 ) $ (551 )
Schedule of Unrecognized Tax Benefits Roll Forward	The following tables present changes to unrecognized tax benefits. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unrecognized tax benefits – January 1 $ 24 $ 6 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 Unrecognized tax benefit increases 105 2 1 1 — — — — Gross decreases – tax positions in prior periods (3 ) — (1 ) (1 ) — — — — Total changes 102 2 — — — — — — Unrecognized tax benefits – December 31 $ 126 $ 8 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unrecognized tax benefits – January 1 $ 25 $ 5 $ 5 $ 5 $ 5 $ 1 $ 1 $ 3 Unrecognized tax benefits increases (decreases) Gross decreases – tax positions in prior periods (2 ) (1 ) — — (4 ) — — — Gross increases – tax positions in prior periods 7 2 4 1 2 — — 1 Decreases due to settlements (6 ) — — — — — — — Total changes (1 ) 1 4 1 (2 ) — — 1 Unrecognized tax benefits – December 31 $ 24 $ 6 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Unrecognized tax benefits – January 1 $ 17 $ 1 $ 2 $ 2 $ 4 $ 4 $ — $ — Unrecognized tax benefits increases (decreases) Gross increases – tax positions in prior periods 12 4 3 3 1 1 1 3 Gross decreases – tax positions in prior periods (4 ) — — — — (4 ) — — Total changes 8 4 3 3 1 (3 ) 1 3 Unrecognized tax benefits – December 31 $ 25 $ 5 $ 5 $ 5 $ 5 $ 1 $ 1 $ 3
Summary of Income Tax Contingencies	The following tables include interest recognized in the Consolidated Statements of Operations and the Consolidated Balance Sheets. Year Ended December 31, 2019 Duke Duke Progress Energy (in millions) Energy Energy Progress Piedmont Net interest income recognized related to income taxes $ 16 $ 1 $ 1 $ — Interest receivable related to income taxes 1 — — — Interest payable related to income taxes 1 — — 1 Year Ended December 31, 2018 Duke Duke Progress Energy (in millions) Energy Energy Progress Net interest income recognized related to income taxes $ 2 $ — $ — Interest payable related to income taxes 3 1 1 Year Ended December 31, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Net interest income recognized related to income taxes $ — $ — $ 1 $ — $ 1 Net interest expense recognized related to income taxes — 2 — — — Interest payable related to income taxes 5 25 1 1 — The following table includes additional information regarding the Duke Energy Registrants' unrecognized tax benefits at December 31, 2019 . It is reasonably possible that Duke Energy will reflect a $3 million decrease in unrecognized tax benefits within the next 12 months. December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Amount that if recognized, would affect the effective tax rate or regulatory liability (a) $ 122 $ 8 $ 9 $ 6 $ 3 $ 1 $ 1 $ 4 (a) The Duke Energy Registrants are unable to estimate the specific amounts that would affect the effective tax rate versus the regulatory liability.

Other Income and Expenses, Net

Other Income and Expenses, Net (Tables)	12 Months Ended
	Dec. 31, 2019
Other Income and Expenses [Abstract]
Schedule of Other Income and Expenses, Net	The components of Other income and expenses, net on the Consolidated Statements of Operations are as follows. Year Ended December 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Interest income $ 31 $ 1 $ 11 $ — $ 11 $ 10 $ 10 $ 1 AFUDC equity 139 42 66 60 6 13 18 — Post in-service equity returns 29 20 7 7 — 1 — — Nonoperating income, other 231 88 57 33 31 — 13 19 Other income and expense, net $ 430 $ 151 $ 141 $ 100 $ 48 $ 24 $ 41 $ 20 Year Ended December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Interest income $ 20 $ 1 $ 18 $ 1 $ 18 $ 7 $ 9 $ 1 AFUDC equity 221 73 104 57 47 11 32 — Post in-service equity returns 15 9 5 5 — 1 — — Nonoperating income, other 143 70 38 24 21 4 4 13 Other income and expense, net $ 399 $ 153 $ 165 $ 87 $ 86 $ 23 $ 45 $ 14 Year Ended December 31, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Interest income $ 13 $ 2 $ 6 $ 2 $ 5 $ 6 $ 8 $ — AFUDC equity 237 106 92 47 45 11 28 — Post in-service equity returns 40 28 12 12 — — — — Nonoperating income, other 218 63 99 54 46 6 11 (11 ) Other income and expense, net $ 508 $ 199 $ 209 $ 115 $ 96 $ 23 $ 47 $ (11 )

Quarterly Financial Data (Una_2

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	Quarterly EPS amounts may not sum to the full-year total due to changes in the weighted average number of common shares outstanding and rounding. First Second Third Fourth (in millions, except per share data) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 6,163 $ 5,873 $ 6,940 $ 6,103 $ 25,079 Operating income 1,373 1,298 1,929 1,109 5,709 Income from continuing operations 893 748 1,323 614 3,578 Loss from discontinued operations, net of tax — — — (7 ) (7 ) Net income 893 748 1,323 607 3,571 Net income available to Duke Energy Corporation common stockholders 900 820 1,327 660 3,707 Earnings per share: Income from continuing operations available to Duke Energy Corporation common stockholders Basic and diluted $ 1.24 $ 1.12 $ 1.82 $ 0.89 $ 5.07 Loss from discontinued operations attributable to Duke Energy Corporation common stockholders Basic and diluted $ — $ — $ — $ (0.01 ) $ (0.01 ) Net income available to Duke Energy Corporation common stockholders Basic and diluted $ 1.24 $ 1.12 $ 1.82 $ 0.88 $ 5.06 2018 Operating revenues $ 6,135 $ 5,643 $ 6,628 $ 6,115 $ 24,521 Operating income 1,256 979 1,579 871 4,685 Income from continuing operations 622 507 1,062 434 2,625 (Loss) Income from discontinued operations, net of tax — (5 ) 4 20 19 Net income 622 502 1,066 454 2,644 Net income attributable to Duke Energy Corporation 620 500 1,082 464 2,666 Earnings per share: Income from continuing operations attributable to Duke Energy Corporation common stockholders Basic and diluted $ 0.88 $ 0.72 $ 1.51 $ 0.62 $ 3.73 (Loss) Income from discontinued operations attributable to Duke Energy Corporation common stockholders Basic and diluted $ — $ (0.01 ) $ — $ 0.03 $ 0.03 Net income attributable to Duke Energy Corporation common stockholders Basic and diluted $ 0.88 $ 0.71 $ 1.51 $ 0.65 $ 3.76
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Impairment Charges (see Notes 4 and 13) $ — $ — $ 25 $ (14 ) $ 11 Total $ — $ — $ 25 $ (14 ) $ 11 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (17 ) $ (20 ) $ (16 ) $ (31 ) $ (84 ) Regulatory and Legislative Impacts (see Note 4) (86 ) (179 ) — — (265 ) Sale of Retired Plant (see Note 3) (107 ) — — — (107 ) Impairment Charges (see Notes 4, 12 and 13) (55 ) — (93 ) (60 ) (208 ) Severance Charges (see Note 21) — — — (187 ) (187 ) Impacts of the Tax Act (see Note 24) (76 ) — 3 53 (20 ) Total $ (341 ) $ (199 ) $ (106 ) $ (225 ) $ (871 )
Duke Energy Carolinas
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY CAROLINAS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 1,744 $ 1,713 $ 2,162 $ 1,776 $ 7,395 Operating income 435 451 793 347 2,026 Net income 293 301 590 219 1,403 2018 Operating revenues $ 1,763 $ 1,672 $ 2,090 $ 1,775 $ 7,300 Operating income 482 224 713 241 1,660 Net income 323 117 496 135 1,071
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (4 ) $ (2 ) $ (2 ) $ (1 ) $ (9 ) Regulatory and Legislative Impacts (see Note 4) (19 ) (179 ) — — (198 ) Severance Charges (see Note 21) — — — (102 ) (102 ) Impacts of the Tax Act (see Note 24) — — (1 ) — (1 ) Total $ (23 ) $ (181 ) $ (3 ) $ (103 ) $ (310 )
Progress Energy
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	PROGRESS ENERGY First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 2,572 $ 2,744 $ 3,242 $ 2,644 $ 11,202 Operating income 488 580 786 447 2,301 Net income 248 329 521 229 1,327 Net income attributable to Parent 249 328 521 229 1,327 2018 Operating revenues $ 2,576 $ 2,498 $ 3,045 $ 2,609 $ 10,728 Operating income 447 484 663 334 1,928 Net income 237 267 406 123 1,033 Net income attributable to Parent 235 265 404 123 1,027
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Impairment Charges (see Note 4) $ — $ — $ 25 $ 11 $ 36 Total $ — $ — $ 25 $ 11 $ 36 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (4 ) $ (3 ) $ (1 ) $ (2 ) $ (10 ) Regulatory and Legislative Impacts (see Note 4) (67 ) — — — (67 ) Impairment Charges (see Note 4) — — — (60 ) (60 ) Severance Charges (see Note 21) — — — (69 ) (69 ) Impacts of the Tax Act (see Note 24) (1 ) — (5 ) (19 ) (25 ) Total $ (72 ) $ (3 ) $ (6 ) $ (150 ) $ (231 )
Duke Energy Progress
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY PROGRESS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 1,484 $ 1,387 $ 1,688 $ 1,398 $ 5,957 Operating income 300 259 373 236 1,168 Net income 203 169 278 155 805 2018 Operating revenues $ 1,460 $ 1,291 $ 1,582 $ 1,366 $ 5,699 Operating income 269 233 330 227 1,059 Net income 177 139 216 135 667
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (2 ) $ (2 ) $ (1 ) $ (1 ) $ (6 ) Regulatory and Legislative Impacts (see Note 4) (67 ) — — — (67 ) Severance Charges (see Note 21) — — — (52 ) (52 ) Impacts of the Tax Act (see Note 24) — — (4 ) (15 ) (19 ) Total $ (69 ) $ (2 ) $ (5 ) $ (68 ) $ (144 )
Duke Energy Florida
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY FLORIDA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 1,086 $ 1,353 $ 1,548 $ 1,244 $ 5,231 Operating income 188 321 413 205 1,127 Net income 96 201 289 106 692 2018 Operating revenues $ 1,115 $ 1,203 $ 1,462 $ 1,241 $ 5,021 Operating income 173 245 331 107 856 Net income 103 168 243 40 554
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Impairment Charges (see Note 4) $ — $ — $ 25 $ 11 $ 36 Total $ — $ — $ 25 $ 11 $ 36 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (2 ) $ (1 ) $ — $ (1 ) $ (4 ) Impairment Charges (see Note 4) — — — (60 ) (60 ) Severance Charges (see Note 21) — — — (17 ) (17 ) Impacts of the Tax Act (see Note 24) — — (2 ) 2 — Total $ (2 ) $ (1 ) $ (2 ) $ (76 ) $ (81 )
Duke Energy Ohio
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY OHIO First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 531 $ 433 $ 489 $ 487 $ 1,940 Operating income 104 74 108 78 364 Net income 69 47 74 48 238 2018 Operating revenues $ 524 $ 459 $ 469 $ 505 $ 1,957 Operating (loss) income (21 ) 77 139 93 288 Net (loss) income (25 ) 46 100 55 176
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (3 ) $ (5 ) $ — $ (6 ) $ (14 ) Sale of Retired Plant (see Note 3) (107 ) — — — (107 ) Severance Charges (see Note 21) — — — (6 ) (6 ) Impacts of the Tax Act (see Note 24) — — — (2 ) (2 ) Total $ (110 ) $ (5 ) $ — $ (14 ) $ (129 )
Duke Energy Indiana
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY INDIANA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 768 $ 714 $ 807 $ 715 $ 3,004 Operating income 169 148 235 133 685 Net income 110 97 156 73 436 2018 Operating revenues $ 731 $ 738 $ 819 $ 771 $ 3,059 Operating income 168 169 173 133 643 Net income 100 98 119 76 393
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ — $ — $ (2 ) $ — $ (2 ) Severance Charges (see Note 21) — — — (7 ) (7 ) Total $ — $ — $ (2 ) $ (7 ) $ (9 )
Piedmont
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2019 Operating revenues $ 579 $ 209 $ 168 $ 425 $ 1,381 Operating income (loss) 172 6 (13 ) 139 304 Net income (loss) 122 (7 ) (18 ) 105 202 2018 Operating revenues $ 553 $ 215 $ 172 $ 435 $ 1,375 Operating income (loss) 161 5 (19 ) 79 226 Net income (loss) 110 (8 ) (21 ) 48 129
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during 2018. There were no unusual or infrequently occurring items for the year ended December 31, 2019. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2018 Costs to Achieve Piedmont Merger (see Note 2) $ (6 ) $ (9 ) $ (11 ) $ (22 ) $ (48 ) Severance Charges (see Note 21) — — — (2 ) (2 ) Total $ (6 ) $ (9 ) $ (11 ) $ (24 ) $ (50 )

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Other Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Assets
Organization And Basis Of Presentation [Line Items]
Taxes receivable	$ 357	$ 729
Current Liabilities
Organization And Basis Of Presentation [Line Items]
Accrued compensation	862	793
Duke Energy Carolinas | Current Liabilities
Organization And Basis Of Presentation [Line Items]
Accrued compensation	271	251
Other accrued liabilities	147	55
Progress Energy | Current Liabilities
Organization And Basis Of Presentation [Line Items]
Customer deposits	354	345
Duke Energy Florida | Current Liabilities
Organization And Basis Of Presentation [Line Items]
Other accrued liabilities	89	85
Customer deposits	209	208
Duke Energy Indiana | Current Assets
Organization And Basis Of Presentation [Line Items]
Taxes receivable	44	9
Duke Energy Indiana | Current Liabilities
Organization And Basis Of Presentation [Line Items]
Customer deposits	$ 49	$ 47

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)MW
Accounting Policies [Abstract]
Sale of noncontrolling interest	$ 428
Plant capacity sold (in MW) | MW	718
Allocation of losses to noncontrolling tax equity members	$ 165

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 311	$ 442
Other	222	141
Other Noncurrent Assets
Other	40	8
Total cash, cash equivalents and restricted cash	573	591	$ 505	$ 541
Progress Energy
Current Assets
Cash and cash equivalents	48	67
Other	39	39
Other Noncurrent Assets
Other	39	6
Total cash, cash equivalents and restricted cash	126	112	87	110
Duke Energy Florida
Current Assets
Cash and cash equivalents	17	36
Other	39	39
Other Noncurrent Assets
Other	0	0
Total cash, cash equivalents and restricted cash	$ 56	$ 75	$ 53	$ 69

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Inventory) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Public Utilities, Inventory [Line Items]
Materials and supplies	$ 2,297	$ 2,238
Coal	586	491
Natural gas, oil, other	349	355
Total inventory	3,232	3,084
Duke Energy Carolinas
Public Utilities, Inventory [Line Items]
Materials and supplies	768	731
Coal	187	175
Natural gas, oil, other	41	42
Total inventory	996	948
Progress Energy
Public Utilities, Inventory [Line Items]
Materials and supplies	1,038	1,049
Coal	186	192
Natural gas, oil, other	199	218
Total inventory	1,423	1,459
Duke Energy Progress
Public Utilities, Inventory [Line Items]
Materials and supplies	686	734
Coal	138	106
Natural gas, oil, other	110	114
Total inventory	934	954
Duke Energy Florida
Public Utilities, Inventory [Line Items]
Materials and supplies	351	315
Coal	48	86
Natural gas, oil, other	90	103
Total inventory	489	504
Duke Energy Ohio
Public Utilities, Inventory [Line Items]
Materials and supplies	79	84
Coal	15	14
Natural gas, oil, other	41	28
Total inventory	135	126
Duke Energy Indiana
Public Utilities, Inventory [Line Items]
Materials and supplies	318	312
Coal	198	109
Natural gas, oil, other	1	1
Total inventory	517	422
Piedmont
Public Utilities, Inventory [Line Items]
Materials and supplies	5	2
Natural gas, oil, other	67	68
Total inventory	$ 72	$ 70

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Property, Plant and Equipment) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	3.10%	3.00%	2.80%
Duke Energy Carolinas
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.80%	2.80%	2.80%
Progress Energy
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	3.10%	2.90%	2.60%
Duke Energy Progress
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	3.10%	2.90%	2.60%
Duke Energy Florida
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	3.10%	3.00%	2.80%
Duke Energy Ohio
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.60%	2.80%	2.80%
Duke Energy Indiana
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	3.30%	3.30%	3.00%
Piedmont
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.40%	2.50%	2.30%

Summary of Significant Accoun_9

Summary of Significant Accounting Policies (Excise Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization And Basis Of Presentation [Line Items]
Excise taxes	$ 421	$ 405	$ 376
Duke Energy Carolinas
Organization And Basis Of Presentation [Line Items]
Excise taxes	39	35	36
Progress Energy
Organization And Basis Of Presentation [Line Items]
Excise taxes	256	241	220
Duke Energy Progress
Organization And Basis Of Presentation [Line Items]
Excise taxes	21	19	19
Duke Energy Florida
Organization And Basis Of Presentation [Line Items]
Excise taxes	235	222	201
Duke Energy Ohio
Organization And Basis Of Presentation [Line Items]
Excise taxes	101	105	98
Duke Energy Indiana
Organization And Basis Of Presentation [Line Items]
Excise taxes	23	22	20
Piedmont
Organization And Basis Of Presentation [Line Items]
Excise taxes	$ 2	$ 2	$ 2

Summary of Significant Accou_10

Summary of Significant Accounting Policies (Expected Reserve for Credit Losses) (Details) - Adjustment - ASU 2016-13 $ in Millions	Dec. 31, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 120
Duke Energy Carolinas
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	16
Progress Energy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	2
Duke Energy Progress
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	1
Duke Energy Florida
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	1
Piedmont
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 1

Acquisitions and Dispositions (

Acquisitions and Dispositions (Acquisitions Narrative) (Details) - USD ($) $ in Millions	Oct. 03, 2016	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Pretax transaction and integration costs		$ 31	$ 16	$ 20	$ 17		$ 84
Impairment charges						$ (8)	402	$ 282
Piedmont
Business Acquisition [Line Items]
Total cash purchase price	$ 5,000
Long-term debt assumed	$ 2,000
Pretax transaction and integration costs							84	103
Impairment charges								7
Piedmont | Operation, maintenance and other
Business Acquisition [Line Items]
Pretax transaction and integration costs								64
Piedmont | System Integration Costs
Business Acquisition [Line Items]
Pretax transaction and integration costs							$ 78	$ 71

Acquisitions and Dispositions_2

Acquisitions and Dispositions (Dispositions Narrative) (Details) $ in Millions	Sep. 06, 2019USD ($)asset	Dec. 31, 2019USD ($)	[1]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of noncontrolling interest	$ 466	$ (407)
Sale of noncontrolling interest tax benefit	8
Commercial Renewables | Certain Renewable Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sales of discontinued operations and other assets, net of cash divested	$ 415
Commercial Renewables | Operating Wind, Solar And Battery Storage Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portion of portfolio sold	49.00%
Number of portions of portfolios sold | asset	37
Commercial Renewables | Operating Solar Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portion of portfolio sold	33.00%
Number of portions of portfolios sold | asset	11
[1]	See Note 3 for additional discussion of the transaction. (f) Amounts in Retained Earnings and AOCI primarily represent impacts to accumulated other comprehensive income due to implementation of a new accounting standard related to Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Loss on sale									$ 4	$ 89	$ (28)
Operation, maintenance and other									6,066	6,463	5,944
Revenues	$ 6,103	$ 6,940	$ 5,873	$ 6,163	$ 6,115	$ 6,628	$ 5,643	$ 6,135	25,079	24,521	23,565
Duke Energy Progress
Segment Reporting Information [Line Items]
Loss on sale										(9)	(4)
Operation, maintenance and other									1,446	1,578	1,439
Revenues	1,398	1,688	1,387	1,484	1,366	1,582	1,291	1,460	$ 5,957	5,699	5,129
Number of reportable segments | segment									1
Duke Energy Ohio
Segment Reporting Information [Line Items]
Loss on sale										106	(1)
Operation, maintenance and other									$ 520	480	530
Revenues	$ 487	$ 489	$ 433	$ 531	$ 505	$ 469	$ 459	$ 524	$ 1,940	1,957	1,923
Number of reportable segments | segment									2
Revenues | Duke Energy Progress | Customer Concentration
Segment Reporting Information [Line Items]
Revenues									$ 635
Beckjord
Segment Reporting Information [Line Items]
Loss on sale										106
Operation, maintenance and other										1
Commercial Renewables
Segment Reporting Information [Line Items]
Revenues									$ 487	$ 477	$ 460

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	$ 6,103	$ 6,940	$ 5,873	$ 6,163	$ 6,115	$ 6,628	$ 5,643	$ 6,135	$ 25,079	$ 24,521	$ 23,565
Interest expense									2,204	2,094	1,986
Depreciation and amortization									4,548	4,074	3,527
Equity in earnings of unconsolidated affiliates									162	83	119
Income tax expense (benefit) from continuing operations									519	448	1,196
Segment income (loss)									3,714	2,647	3,065
Add back noncontrolling interests component									(177)	(22)	5
Add back preferred stock dividend									41
(Loss) Income From Discontinued Operations, net of tax	(7)				20	4	(5)	0	(7)	19	(6)
Net income (loss)	607	1,323	748	893	454	1,066	502	622	3,571	2,644	3,064
Net income (loss) attributable to parent					464	1,082	500	620	3,748	2,666	3,059
Capital expenditures									11,446	9,668	8,198
Segment assets	158,838				145,392				158,838	145,392	137,914
Segment Reporting Information Assets [Abstract]
Reduction of prior year impairment	(14)	25							11
After-tax severance charges					187				16	187	15
After-tax loss on sale and retirement								(107)		(107)
Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	487	489	433	531	505	469	459	524	1,940	1,957	1,923
Interest expense									109	92	91
Depreciation and amortization									265	268	261
Income tax expense (benefit) from continuing operations									40	43	59
Segment income (loss)									239	176	193
(Loss) Income From Discontinued Operations, net of tax									(1)		(1)
Net income (loss) attributable to parent	48	$ 74	$ 47	$ 69	55	$ 100	46	(25)	238	176	192
Capital expenditures									952	827	686
Segment assets	9,338				8,555				9,338	8,555	7,875
Segment Reporting Information Assets [Abstract]
Tax Act					2					2
After-tax severance charges					6					6
After-tax loss on sale and retirement								107		107
Regulatory settlements
Segment Reporting Information Assets [Abstract]
Regulatory settlement charges							$ 179	$ 86		265
Noncontrolling Interests
Segment Reporting Information, Profit (Loss) [Abstract]
Net income (loss)										(22)	5
Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									(200)	(199)	(200)
Interest expense									(58)	(45)	(20)
Depreciation and amortization									(5)	(1)
Segment assets	188				188				188	188	188
Eliminations | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Segment assets											(15)
Electric Utilities and Infrastructure
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									22,798	22,242	21,300
Equity in earnings of unconsolidated affiliates									9	6	5
Segment Reporting Information Assets [Abstract]
Tax Act										24	231
Electric Utilities and Infrastructure | After-tax impairment charge
Segment Reporting Information Assets [Abstract]
After tax impairment charge										46
Electric Utilities and Infrastructure | Regulatory settlements
Segment Reporting Information Assets [Abstract]
Regulatory settlement charges										202	98
Electric Utilities and Infrastructure | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									22,831	22,273	21,331
Interest expense									1,345	1,288	1,240
Depreciation and amortization									3,951	3,523	3,010
Equity in earnings of unconsolidated affiliates									9	5	5
Income tax expense (benefit) from continuing operations									785	799	1,355
Segment income (loss)									3,536	3,058	3,210
Capital expenditures									8,263	8,086	7,024
Segment assets	135,561				125,364				135,561	125,364	119,423
Segment Reporting Information Assets [Abstract]
Reduction of prior year impairment									27
Electric Utilities and Infrastructure | Operating Segments | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									1,456	1,450	1,373
Interest expense									80	67	62
Depreciation and amortization									182	183	178
Income tax expense (benefit) from continuing operations									20	47	40
Segment income (loss)									159	186	138
Capital expenditures									680	655	491
Segment assets	6,188				5,643				6,188	5,643	5,066
Electric Utilities and Infrastructure | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									33	31	31
Gas Utilities and Infrastructure
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									1,770	1,783	1,743
Equity in earnings of unconsolidated affiliates									114	27	62
Segment Reporting Information Assets [Abstract]
Tax Act										1	26
Gas Utilities and Infrastructure | After-tax impairment charge
Segment Reporting Information Assets [Abstract]
After tax impairment charge									19	42
Gas Utilities and Infrastructure | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									1,866	1,881	1,836
Interest expense									117	106	105
Depreciation and amortization									256	245	231
Equity in earnings of unconsolidated affiliates									114	27	62
Income tax expense (benefit) from continuing operations									22	78	116
Segment income (loss)									432	274	319
Capital expenditures									1,539	1,133	907
Segment assets	13,921				12,361				13,921	12,361	11,462
Gas Utilities and Infrastructure | Operating Segments | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									484	506	508
Interest expense									29	24	28
Depreciation and amortization									83	85	83
Income tax expense (benefit) from continuing operations									21	24	39
Segment income (loss)									85	93	85
Capital expenditures									272	172	195
Segment assets	3,116				2,874				3,116	2,874	2,758
Gas Utilities and Infrastructure | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									96	98	93
Commercial Renewables
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									487	477	460
Equity in earnings of unconsolidated affiliates									(4)	(1)	(5)
Segment Reporting Information Assets [Abstract]
After tax impairment charge										91	74
Tax Act										3	442
Commercial Renewables | Noncontrolling Interests
Segment Reporting Information Assets [Abstract]
After tax impairment charge										2
Commercial Renewables | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									487	477	460
Interest expense									95	88	87
Depreciation and amortization									168	155	155
Equity in earnings of unconsolidated affiliates									(4)	(1)	(5)
Income tax expense (benefit) from continuing operations									(115)	(147)	(628)
Segment income (loss)									198	9	441
Capital expenditures									1,423	193	92
Segment assets	6,020				4,204				6,020	4,204	4,156
Commercial Renewables | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									0		0
Other
Segment Reporting Information, Profit (Loss) [Abstract]
Equity in earnings of unconsolidated affiliates									43	51	57
Segment Reporting Information Assets [Abstract]
After-tax severance charges										144
After-tax loss on sale and retirement										82
Total Reportable Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									25,055	24,502	23,503
Total Reportable Segments | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									25,184	24,631	23,627
Interest expense									1,557	1,482	1,432
Depreciation and amortization									4,375	3,923	3,396
Equity in earnings of unconsolidated affiliates									119	31	62
Income tax expense (benefit) from continuing operations									692	730	843
Segment income (loss)									4,166	3,341	3,970
Capital expenditures									11,225	9,412	8,023
Segment assets	155,502				141,929				155,502	141,929	135,041
Total Reportable Segments | Operating Segments | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									1,940	1,956	1,881
Interest expense									109	91	90
Depreciation and amortization									265	268	261
Income tax expense (benefit) from continuing operations									41	71	79
Segment income (loss)									244	279	223
Capital expenditures									952	827	686
Segment assets	9,304				8,517				9,304	8,517	7,824
Total Reportable Segments | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									129	129	124
Other
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									24	19	62
Segment Reporting Information Assets [Abstract]
Tax Act										2	597
Costs to achieve mergers, acquisition costs										65	64
Other | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									71	70	76
Other | Other
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues									95	89	138
Interest expense									705	657	574
Depreciation and amortization									178	152	131
Equity in earnings of unconsolidated affiliates									43	52	57
Income tax expense (benefit) from continuing operations									(173)	(282)	353
Segment income (loss)									(452)	(694)	(905)
Capital expenditures									221	256	175
Segment assets	3,148				3,275				3,148	3,275	2,685
Other | Other | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										1	42
Interest expense										1	1
Income tax expense (benefit) from continuing operations									(1)	(28)	(20)
Segment income (loss)									(5)	(103)	(30)
Segment assets	$ 34				$ 38				$ 34	$ 38	$ 66

Business Segments (Major Custom

Business Segments (Major Customer Disclosure) (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Revenue, Major Customer [Line Items]
Revenues	$ 6,103	$ 6,940	$ 5,873	$ 6,163	$ 6,115	$ 6,628	$ 5,643	$ 6,135	$ 25,079	$ 24,521	$ 23,565
Duke Energy Progress
Revenue, Major Customer [Line Items]
Revenues	$ 1,398	$ 1,688	$ 1,387	$ 1,484	$ 1,366	$ 1,582	$ 1,291	$ 1,460	$ 5,957	$ 5,699	$ 5,129
Number of reportable segments | segment									1

Business Segments (Schedule of

Business Segments (Schedule of Revenue, By Products and Services) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 6,103	$ 6,940	$ 5,873	$ 6,163	$ 6,115	$ 6,628	$ 5,643	$ 6,135	$ 25,079	$ 24,521	$ 23,565
Electric Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									22,798	22,242	21,300
Gas Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									1,770	1,783	1,743
Commercial Renewables
Segment Reporting Information [Line Items]
Revenues									487	477	460
Total Reportable Segments
Segment Reporting Information [Line Items]
Revenues									25,055	24,502	23,503
Retail Electric
Segment Reporting Information [Line Items]
Revenues									19,745	19,013	18,177
Retail Electric | Electric Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									19,745	19,013	18,177
Wholesale Electric
Segment Reporting Information [Line Items]
Revenues									2,620	2,720	2,479
Wholesale Electric | Electric Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									2,231	2,345	2,104
Wholesale Electric | Commercial Renewables
Segment Reporting Information [Line Items]
Revenues									389	375	375
Retail Natural Gas
Segment Reporting Information [Line Items]
Revenues									1,782	1,817	1,732
Retail Natural Gas | Gas Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									1,782	1,817	1,732
Other
Segment Reporting Information [Line Items]
Revenues									1,037	1,081	1,239
Other | Electric Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									855	915	1,050
Other | Gas Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									84	64	104
Other | Commercial Renewables
Segment Reporting Information [Line Items]
Revenues									98	102	85
Operating Segments | Electric Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									22,831	22,273	21,331
Operating Segments | Gas Utilities and Infrastructure
Segment Reporting Information [Line Items]
Revenues									1,866	1,881	1,836
Operating Segments | Commercial Renewables
Segment Reporting Information [Line Items]
Revenues									487	477	460
Operating Segments | Total Reportable Segments
Segment Reporting Information [Line Items]
Revenues									$ 25,184	$ 24,631	$ 23,627

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	$ 15,018	$ 15,622
Regulatory Assets: Current	1,796	2,005
Other Noncurrent Assets: Regulatory assets	13,222	13,617
Total regulatory liabilities	16,048	15,432
Less: current portion	784	598
Total noncurrent regulatory liabilities	15,264	14,834
Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	7,872	8,058
Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	5,756	5,421
AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1,100	538
Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	176	301
Amounts to be refunded to customers
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	34	34
Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1	16
Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1,109	1,064
AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	4,084	4,255
AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	739	772
Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	2,391	2,654
Storm cost deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,399	1,117
Nuclear asset securitized balance, net
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,042	1,093
Debt fair value adjustment
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,019	1,099
Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	528	838
Deferred asset – Lee and Harris COLA
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	388	426
Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	356	204
Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	343	449
Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	338	367
Retired generation facilities
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	331	402
Post-in-service carrying costs (PISCC) and deferred operating expenses
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	329	320
Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	214	213
Derivatives – natural gas supply contracts
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	117	141
Nuclear deferral
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	107	133
Manufactured gas plant (MGP)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	102	99
Deferred pipeline integrity costs
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	79	65
NCEMPA deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	72	50
East Bend deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	44	47
Transmission expansion obligation
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	36	39
Amounts due from customers
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	36	24
Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	28	31
Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	896	784
Progress Energy
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	7,292	7,701
Regulatory Assets: Current	946	1,137
Other Noncurrent Assets: Regulatory assets	6,346	6,564
Total regulatory liabilities	5,555	5,329
Less: current portion	330	280
Total noncurrent regulatory liabilities	5,225	5,049
Progress Energy | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	2,595	2,710
Progress Energy | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	2,561	2,135
Progress Energy | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities		149
Progress Energy | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1	16
Progress Energy | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	398	319
Progress Energy | AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,843	2,061
Progress Energy | AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	668	601
Progress Energy | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	897	1,074
Progress Energy | Storm cost deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,214	953
Progress Energy | Nuclear asset securitized balance, net
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,042	1,093
Progress Energy | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	305	600
Progress Energy | Deferred asset – Lee and Harris COLA
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	38	43
Progress Energy | Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	129	74
Progress Energy | Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	241	256
Progress Energy | Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	114	127
Progress Energy | Retired generation facilities
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	266	324
Progress Energy | Post-in-service carrying costs (PISCC) and deferred operating expenses
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	33	36
Progress Energy | Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	41	41
Progress Energy | Nuclear deferral
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	40	46
Progress Energy | NCEMPA deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	72	50
Progress Energy | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	349	322
Duke Energy Carolinas
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	3,910	3,977
Regulatory Assets: Current	550	520
Other Noncurrent Assets: Regulatory assets	3,360	3,457
Total regulatory liabilities	6,678	6,198
Less: current portion	255	199
Total noncurrent regulatory liabilities	6,423	5,999
Duke Energy Carolinas | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	3,060	3,082
Duke Energy Carolinas | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1,936	1,968
Duke Energy Carolinas | AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1,100	538
Duke Energy Carolinas | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	39	38
Duke Energy Carolinas | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	543	572
Duke Energy Carolinas | AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,696	1,725
Duke Energy Carolinas | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	477	581
Duke Energy Carolinas | Storm cost deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	178	160
Duke Energy Carolinas | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	222	196
Duke Energy Carolinas | Deferred asset – Lee and Harris COLA
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	350	383
Duke Energy Carolinas | Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	198	101
Duke Energy Carolinas | Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	100	169
Duke Energy Carolinas | Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	166	176
Duke Energy Carolinas | Retired generation facilities
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	16	21
Duke Energy Carolinas | Post-in-service carrying costs (PISCC) and deferred operating expenses
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	33	34
Duke Energy Carolinas | Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	80	78
Duke Energy Carolinas | Nuclear deferral
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	67	87
Duke Energy Carolinas | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	327	266
Duke Energy Progress
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	4,678	4,814
Regulatory Assets: Current	526	703
Other Noncurrent Assets: Regulatory assets	4,152	4,111
Total regulatory liabilities	4,468	4,133
Less: current portion	236	178
Total noncurrent regulatory liabilities	4,232	3,955
Duke Energy Progress | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1,802	1,863
Duke Energy Progress | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	2,294	1,878
Duke Energy Progress | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities		93
Duke Energy Progress | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	372	299
Duke Energy Progress | AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,834	2,051
Duke Energy Progress | AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	509	429
Duke Energy Progress | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	423	542
Duke Energy Progress | Storm cost deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	801	571
Duke Energy Progress | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	266	397
Duke Energy Progress | Deferred asset – Lee and Harris COLA
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	38	43
Duke Energy Progress | Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	85	54
Duke Energy Progress | Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	216	235
Duke Energy Progress | Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	61	67
Duke Energy Progress | Retired generation facilities
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	83	105
Duke Energy Progress | Post-in-service carrying costs (PISCC) and deferred operating expenses
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	33	36
Duke Energy Progress | Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	41	41
Duke Energy Progress | Nuclear deferral
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	40	46
Duke Energy Progress | NCEMPA deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	72	50
Duke Energy Progress | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	176	147
Duke Energy Florida
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	2,613	2,888
Regulatory Assets: Current	419	434
Other Noncurrent Assets: Regulatory assets	2,194	2,454
Total regulatory liabilities	1,087	1,196
Less: current portion	94	102
Total noncurrent regulatory liabilities	993	1,094
Duke Energy Florida | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	793	847
Duke Energy Florida | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	267	257
Duke Energy Florida | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities		56
Duke Energy Florida | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1	16
Duke Energy Florida | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	26	20
Duke Energy Florida | AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	9	10
Duke Energy Florida | AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	159	172
Duke Energy Florida | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	474	532
Duke Energy Florida | Storm cost deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	413	382
Duke Energy Florida | Nuclear asset securitized balance, net
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,042	1,093
Duke Energy Florida | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	39	203
Duke Energy Florida | Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	44	20
Duke Energy Florida | Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	25	21
Duke Energy Florida | Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	53	60
Duke Energy Florida | Retired generation facilities
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	183	219
Duke Energy Florida | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	172	176
Duke Energy Ohio
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	598	564
Regulatory Assets: Current	49	33
Other Noncurrent Assets: Regulatory assets	549	531
Total regulatory liabilities	827	897
Less: current portion	64	57
Total noncurrent regulatory liabilities	763	840
Duke Energy Ohio | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	654	678
Duke Energy Ohio | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	86	126
Duke Energy Ohio | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	16	18
Duke Energy Ohio | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	71	75
Duke Energy Ohio | AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	16	20
Duke Energy Ohio | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	155	146
Duke Energy Ohio | Storm cost deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	7	4
Duke Energy Ohio | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1	2
Duke Energy Ohio | Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	6	5
Duke Energy Ohio | Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	2	10
Duke Energy Ohio | Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	40	46
Duke Energy Ohio | Post-in-service carrying costs (PISCC) and deferred operating expenses
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	17	17
Duke Energy Ohio | Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	5	5
Duke Energy Ohio | Manufactured gas plant (MGP)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	102	99
Duke Energy Ohio | Deferred pipeline integrity costs
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	17	14
Duke Energy Ohio | East Bend deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	44	47
Duke Energy Ohio | Transmission expansion obligation
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	40	43
Duke Energy Ohio | Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	28	31
Duke Energy Ohio | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	118	75
Duke Energy Indiana
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	1,172	1,157
Regulatory Assets: Current	90	175
Other Noncurrent Assets: Regulatory assets	1,082	982
Total regulatory liabilities	1,740	1,747
Less: current portion	55	25
Total noncurrent regulatory liabilities	1,685	1,722
Duke Energy Indiana | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	1,008	1,009
Duke Energy Indiana | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	599	628
Duke Energy Indiana | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	90	67
Duke Energy Indiana | Amounts to be refunded to customers
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities		1
Duke Energy Indiana | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	43	42
Duke Energy Indiana | AROs – coal ash
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	529	450
Duke Energy Indiana | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	243	222
Duke Energy Indiana | Deferred fuel and purchased power
Regulatory Assets Liabilities [Line Items]
Total regulatory assets		40
Duke Energy Indiana | Hedge costs deferrals
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	23	24
Duke Energy Indiana | Demand side management (DSM)/Energy Efficiency (EE)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets		14
Duke Energy Indiana | Advanced metering infrastructure (AMI)
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	18	18
Duke Energy Indiana | Retired generation facilities
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	49	57
Duke Energy Indiana | Post-in-service carrying costs (PISCC) and deferred operating expenses
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	246	233
Duke Energy Indiana | Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	12	11
Duke Energy Indiana | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	52	88
Piedmont
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	363	357
Regulatory Assets: Current	73	54
Other Noncurrent Assets: Regulatory assets	290	303
Total regulatory liabilities	1,212	1,218
Less: current portion	81	37
Total noncurrent regulatory liabilities	1,131	1,181
Piedmont | Net regulatory liability related to income taxes
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	555	579
Piedmont | Costs of removal
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	574	564
Piedmont | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	3	1
Piedmont | Amounts to be refunded to customers
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	34	33
Piedmont | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory liabilities	46	41
Piedmont | AROs – nuclear and other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	16	19
Piedmont | Accrued pension and OPEB
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	90	99
Piedmont | Vacation accrual
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	12	12
Piedmont | Derivatives – natural gas supply contracts
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	117	141
Piedmont | Deferred pipeline integrity costs
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	62	51
Piedmont | Amounts due from customers
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	36	24
Piedmont | Other
Regulatory Assets Liabilities [Line Items]
Total regulatory assets	$ 30	$ 11

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	Apr. 02, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other		$ 6,066	$ 6,463	$ 5,944
Hurricane Florence, Hurricane Michael and Winter Storm Diego
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other	$ 553
Estimated capital cost	96
Duke Energy Ohio
Public Utilities, General Disclosures [Line Items]
Limit of total capital		30.00%
Operation, maintenance and other		$ 520	480	530
Duke Energy Kentucky
Public Utilities, General Disclosures [Line Items]
Required minimum equity capital structure		35.00%
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other		$ 1,868	2,130	2,021
Duke Energy Carolinas | Hurricane Florence, Hurricane Michael and Winter Storm Diego
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other	171
Estimated capital cost	20
Duke Energy Progress
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other		$ 1,446	$ 1,578	$ 1,439
Duke Energy Progress | Hurricane Florence, Hurricane Michael and Winter Storm Diego
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other	382
Estimated capital cost	$ 76

Regulatory Matters (Duke Energy

Regulatory Matters (Duke Energy Carolinas Narrative) (Details) $ in Millions

Sep. 30, 2019USD ($)

May 21, 2019USD ($)

Nov. 08, 2018USD ($)

Aug. 09, 2018plant

Jul. 05, 2018plant

Jun. 22, 2018USD ($)

Feb. 15, 2018USD ($)

Aug. 25, 2017USD ($)

May 31, 2018USD ($)plantMW

Feb. 28, 2018USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Aug. 16, 2019USD ($)

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

$ 6,066

$ 6,463

$ 5,944

Regulatory assets

15,018

15,622

AROs – coal ash

Public Utilities, General Disclosures [Line Items]

Regulatory assets

4,084

4,255

Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

1,868

2,130

$ 2,021

Regulatory assets

3,910

3,977

Duke Energy Carolinas | AROs – coal ash

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 1,696

$ 1,725

Duke Energy Carolinas | NCUC | 2017 North Carolina Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 647

Requested rate increase (decrease), percent

13.60%

Requested return on equity, percentage

9.90%

Requested capital structure, percentage

52.00%

Requested debt structure, percentage

48.00%

Operation, maintenance and other

$ 4

Impairment charges and Operation

$ 150

Management penalty assessed

70

Reduction of annual recovery of deferred coal ash costs

$ 14

Duke Energy Carolinas | NCUC | 2019 North Carolina Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 291

Requested rate increase (decrease), percent

6.00%

Requested gross rate case revenue increase

$ 445

Requested EDIT rider decrease

$ 154

Duke Energy Carolinas | NCUC | 2018 Sale of Hydro Plants

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 32

Number of Hydroelectric Plants | plant

5

Plant capacity | MW

18.7

Total estimated loss on the sale

$ 40

Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 168

Requested rate increase (decrease), percent

10.00%

Tax benefit from change in enacted tax rates

$ (66)

$ 66

Measurement period adjustments

$ 45

$ 46

Approved return on equity, percentage

9.50%

Approved capital structure, percentage

53.00%

Approved debt structure, percentage

47.00%

Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case | AROs – coal ash

Public Utilities, General Disclosures [Line Items]

Recovery period

5 years

Regulatory assets

$ 96

$ 242

Denied recovery costs

$ 115

Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case | Deferred project costs

Public Utilities, General Disclosures [Line Items]

Recovery period

12 years

Regulatory assets

$ 125

Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case | State | North Carolina DOR

Public Utilities, General Disclosures [Line Items]

Tax benefit from reduction in state taxes

$ 17

Approved decrease through EDIT Rider

$ 17

Duke Energy Carolinas | FERC | FERC Formula Rate Matter

Public Utilities, General Disclosures [Line Items]

Customer refunds

$ 25

Duke Energy Carolinas | FERC | 2018 Sale of Hydro Plants

Public Utilities, General Disclosures [Line Items]

Number of Hydroelectric Plants | plant

4

Northbrook | Duke Energy Carolinas | NCUC | 2018 Sale of Hydro Plants

Public Utilities, General Disclosures [Line Items]

Number of Hydroelectric Plants | plant

5

Northbrook | Duke Energy Carolinas | NCUC | 2018 Sale of Hydro Plants, CPCNs

Public Utilities, General Disclosures [Line Items]

Number of Hydroelectric Plants | plant

4

Northbrook | Duke Energy Carolinas | FERC | 2018 Sale of Hydro Plants

Public Utilities, General Disclosures [Line Items]

Number of Hydroelectric Plants | plant

4

Regulatory Matters (Duke Ener_2

Regulatory Matters (Duke Energy Progress Narrative) (Details) customer in Thousands, $ in Millions

Oct. 30, 2019USD ($)

Sep. 30, 2019USD ($)customer

May 21, 2019USD ($)

Nov. 08, 2018USD ($)

Nov. 22, 2017

Aug. 25, 2017USD ($)

Jun. 01, 2017USD ($)

Nov. 04, 2015plantMW

Feb. 28, 2018

Mar. 31, 2018USD ($)

Dec. 31, 2019USD ($)MW

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Public Utilities, General Disclosures [Line Items]

Total income (loss) from continuing operations before income taxes

$ 4,097

$ 3,073

$ 4,266

Regulatory assets

15,018

15,622

Net property, plant and equipment

102,127

91,694

Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Total income (loss) from continuing operations before income taxes

962

827

1,007

Regulatory assets

4,678

4,814

Net property, plant and equipment

22,934

20,398

Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Total income (loss) from continuing operations before income taxes

1,714

1,374

$ 1,866

Regulatory assets

3,910

3,977

Net property, plant and equipment

32,397

29,245

2017 North Carolina Rate Case | NCUC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 477

Requested rate increase (decrease), percent

14.90%

Requested rate increase (decrease), amended, amount

$ 420

Requested rate increase (decrease), amended, percentage

13.00%

Requested return on equity, percentage

9.90%

Requested capital structure, percentage

52.00%

Requested debt structure, percentage

48.00%

Total income (loss) from continuing operations before income taxes

$ (68)

2017 North Carolina Rate Case | NCUC | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 647

Requested rate increase (decrease), percent

13.60%

Requested return on equity, percentage

9.90%

Requested capital structure, percentage

52.00%

Requested debt structure, percentage

48.00%

Total income (loss) from continuing operations before income taxes

$ (14)

2019 North Carolina Rate Case | NCUC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 464

Requested rate increase (decrease), percent

12.30%

Requested gross rate case revenue increase

$ 586

Requested rate increase (decrease), rider reduction, tax cuts and jobs act and return deferred revenue

122

Requested EDIT rider decrease

$ 120

2019 North Carolina Rate Case | NCUC | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 291

Requested rate increase (decrease), percent

6.00%

Requested gross rate case revenue increase

$ 445

Requested EDIT rider decrease

$ 154

Hurricane Dorian Storm Damage | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Estimated storm costs - operation maintenance

205

Estimated storm costs - capital investments

$ 4

2018 South Carolina Rate Case | PSCSC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 59

Requested rate increase (decrease), percent

10.30%

Measurement period adjustments

$ (12)

$ (10)

Approved return on equity, percentage

9.50%

Approved capital structure, percentage

53.00%

Approved debt structure, percentage

47.00%

Tax benefit from change in enacted tax rates

$ (17)

2018 South Carolina Rate Case | PSCSC | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 168

Requested rate increase (decrease), percent

10.00%

Measurement period adjustments

$ (45)

$ (46)

Approved return on equity, percentage

9.50%

Approved capital structure, percentage

53.00%

Approved debt structure, percentage

47.00%

Tax benefit from change in enacted tax rates

$ (66)

66

Western Carolinas Modernization Plan | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Number of plants to be constructed | plant

2

Plants to be constructed capacity (in MW) | MW

280

Western Carolinas Modernization Plan | NCUC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Recovery period

10 years

Estimated capital cost

$ 893

North Carolina | Hurricane Dorian Storm Damage | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Customers experiencing outages | customer

270

South Carolina | Hurricane Dorian Storm Damage | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Customers experiencing outages | customer

30

Storm cost deferrals

Public Utilities, General Disclosures [Line Items]

Regulatory assets

1,399

1,117

Storm cost deferrals | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Regulatory assets

801

571

Storm cost deferrals | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Regulatory assets

178

160

Storm cost deferrals | Hurricane Dorian Storm Damage | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Regulatory assets

179

AROs – coal ash

Public Utilities, General Disclosures [Line Items]

Regulatory assets

4,084

4,255

AROs – coal ash | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Regulatory assets

1,834

2,051

AROs – coal ash | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 1,696

1,725

AROs – coal ash | 2018 South Carolina Rate Case | PSCSC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Regulatory assets

4

$ 51

Recovery period

5 years

Denied recovery costs

65

AROs – coal ash | 2018 South Carolina Rate Case | PSCSC | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Regulatory assets

96

$ 242

Recovery period

5 years

Denied recovery costs

115

North Carolina DOR | 2018 South Carolina Rate Case | PSCSC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Measurement period adjustments

$ (17)

State | North Carolina DOR | 2018 South Carolina Rate Case | PSCSC | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Approved increase (decrease) through EDIT Rider

12

$ 12

State | North Carolina DOR | 2018 South Carolina Rate Case | PSCSC | Duke Energy Carolinas

Public Utilities, General Disclosures [Line Items]

Approved increase (decrease) through EDIT Rider

$ (17)

Generating facilities planned for retirement

Public Utilities, General Disclosures [Line Items]

Capacity (in MW) | MW

5,002

Generating facilities planned for retirement | Asheville Plant | Duke Energy Progress

Public Utilities, General Disclosures [Line Items]

Capacity (in MW) | MW

376

Net property, plant and equipment

$ 214

$ 327

Regulatory Matters (Duke Ener_3

Regulatory Matters (Duke Energy Florida Narrative) (Details) customer in Thousands, $ in Millions	Jun. 13, 2019USD ($)	Mar. 25, 2019USD ($)	Dec. 27, 2018USD ($)	Jul. 31, 2018USD ($)	May 31, 2018USD ($)	Jan. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)MW	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Nov. 22, 2019USD ($)	Jan. 29, 2019USD ($)	Oct. 31, 2018customer	Sep. 30, 2017customer	Oct. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment							$ 102,127		$ 91,694	$ 102,127	$ 91,694
Operation, maintenance and other										6,066	6,463	$ 5,944
Regulatory assets							15,018		15,622	15,018	15,622
Remaining net book value							102,127		91,694	102,127	91,694
Impairment charges										(8)	402	282
Reduction of prior year impairment							(14)	$ 25		11
Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment							15,221		13,824	15,221	13,824
Operation, maintenance and other										1,034	1,025	853
Regulatory assets							2,613		2,888	2,613	2,888
Remaining net book value							15,221		13,824	15,221	13,824
Impairment charges										(36)	54	$ 138
Storm Restoration Cost Recovery | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer																1,000
Estimated storm costs, capital and operation maintenance														$ 508
Allowed storm reserve					$ 132
Net property, plant and equipment	$ 18
Operation, maintenance and other	6
Increase (decrease) in storm reserve	$ (24)
Hurricane Michael Storm Damage | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer															72
Estimated storm costs, capital and operation maintenance							311			311
Amount of recovery costs sought													$ 191
Net property, plant and equipment							107		$ 35	107	35
Hurricane Dorian Storm Damage | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Estimated storm costs, capital and operation maintenance							167			167
FPSC | Storm Restoration Cost Recovery | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Estimated storm costs, capital and operation maintenance					510
FPSC | Federal Tax Act Impacts | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Amount of tax act annual tax savings requested rate decrease			$ 4		134
Amount of tax act excess deferred tax amortization requested rate decrease			71		67
FPSC | Federal Tax Act Impacts Revenue Requirement | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)					201
Crystal River Units 3 and 4 | FPSC | Federal Tax Act Impacts Revenue Requirement | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Remaining net book value					50
Citrus County Combined Cycle Facility | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Plant capacity | MW									1,640
Estimated capital cost including Afudc							1,500		$ 1,600	1,500	1,600						$ 1,500
Impairment charges									60
Reduction of prior year impairment										36
Hamilton Project | FPSC | Second Revised And Restated Stipulation And Settlement Agreement 2017 | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission						$ (15)
Columbia Project | FPSC | Second Revised And Restated Stipulation And Settlement Agreement 2017 | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)				$ (14)
Trenton Generation Project | FPSC | Second Revised And Restated Stipulation And Settlement Agreement 2017 | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)		$ 13
Lake Placid Generation Project | FPSC | Second Revised And Restated Stipulation And Settlement Agreement 2017 | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)		8
DeBary Solar Project | FPSC | Second Revised And Restated Stipulation And Settlement Agreement 2017 | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)		$ 11
Storm cost deferrals
Public Utilities, General Disclosures [Line Items]
Regulatory assets							1,399		1,117	1,399	1,117
Storm cost deferrals | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Regulatory assets							413		382	413	382
Storm cost deferrals | Storm Restoration Cost Recovery | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Regulatory assets							43		217	43	217
Storm cost deferrals | Hurricane Michael Storm Damage | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Regulatory assets							$ 204		$ 165	$ 204	$ 165
Storm cost deferrals | FPSC | Federal Tax Act Impacts Revenue Requirement | Duke Energy Florida
Public Utilities, General Disclosures [Line Items]
Regulatory assets			$ 155		$ 151

Regulatory Matters (Duke Ener_4

Regulatory Matters (Duke Energy Ohio Narrative) (Details) $ in Millions

Jan. 31, 2020USD ($)

Sep. 03, 2019USD ($)MW

Jan. 30, 2019USD ($)

Aug. 31, 2018USD ($)

Apr. 13, 2018USD ($)

Apr. 01, 2018USD ($)

Sep. 27, 2017USD ($)

Sep. 26, 2017USD ($)

Mar. 31, 2017USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Jul. 12, 2019USD ($)

Sep. 28, 2018USD ($)

Public Utilities, General Disclosures [Line Items]

Regulated electric

$ 22,615

$ 22,097

$ 21,177

Regulatory assets

15,018

15,622

Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulated electric

1,456

1,450

1,373

Regulatory assets

598

564

Electric Base Rate Case | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 15

Requested return on equity, percentage

10.40%

Requested rate increase (decrease), amended, amount

$ (19)

Requested capital structure, percentage

50.75%

Approved return on equity, percentage

9.84%

Requested debt structure, percentage

49.25%

Approved rate increase (decrease) amount by state commission

$ (20)

Energy Efficiency Cost Recovery Program | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Approved rate increase (decrease) amount by state commission

$ 56

Regulated electric

$ 20

MGP Cost Recovery - 2009 Through 2012 | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulatory assets

55

MGP Cost Recovery - 2013 Through 2017 | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 26

MGP Cost Recovery - 2018 | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulatory assets

20

Duke Energy Kentucky Gas Base Rate Case | KPSC | Duke Energy Kentucky

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 11

Requested rate increase (decrease), amended, amount

$ (5)

Approved return on equity, percentage

9.70%

Approved rate increase (decrease) amount by state commission

$ 7

Requested rate increase (decrease), percent

11.10%

Duke Energy Kentucky Electric Base Rate Case | KPSC | Duke Energy Kentucky

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 46

Requested rate increase (decrease), percent

12.50%

Distribution battery energy storage system (in MW) | MW

3.4

Duke Energy Kentucky Electric Base Rate Case, Kentucky Attorney General | KPSC | Duke Energy Kentucky

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 26

Minimum | Electric Base Rate Case | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ (18)

Requested return on equity, percentage

9.22%

Minimum | Natural Gas Pipeline Extension | Ohio Power Siting Board | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Estimated capital cost excluding AFUDC

163

Maximum | Electric Base Rate Case | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ (29)

Requested return on equity, percentage

10.24%

Requested rider revenue increase

$ 10

Maximum | Energy Efficiency Cost Recovery Program | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Approved rate increase (decrease) amount by state commission

$ 38

Maximum | Natural Gas Pipeline Extension | Ohio Power Siting Board | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Estimated capital cost excluding AFUDC

245

MGP Costs - Regulatory Disallowance | MGP Cost Recovery - 2013 Through 2017 | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 12

MGP Costs - Regulatory Disallowance | MGP Cost Recovery - 2018 | Public Utilities Commission Of Ohio | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 11

RTO Realignment | Duke Energy Ohio

Public Utilities, General Disclosures [Line Items]

Regulatory assets

$ 40

$ 43

Subsequent Event | Duke Energy Kentucky Electric Base Rate Case | KPSC | Duke Energy Kentucky

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease)

$ 44

Regulatory Matters (Duke Ener_5

Regulatory Matters (Duke Energy Ohio - Exit Obligation Rollforward) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Public Utilities, General Disclosures [Line Items]
Balance, beginning of period	$ 205
Cash reductions	(188)
Balance, end of period	41
Duke Energy Ohio
Public Utilities, General Disclosures [Line Items]
Balance, beginning of period	2
Cash reductions	(2)
Balance, end of period	1
RTO Realignment | Duke Energy Ohio
Public Utilities, General Disclosures [Line Items]
Balance, beginning of period	58
Provisions/Adjustments	0
Cash reductions	(4)
Balance, end of period	$ 54

Regulatory Matters (Duke Ener_6

Regulatory Matters (Duke Energy Indiana Narrative) (Details) - Duke Energy Indiana - Indiana Rate Case 2019 - Indiana Utility Regulatory Commission - USD ($) $ in Millions	Dec. 04, 2019	Sep. 09, 2019	Jul. 02, 2019	Dec. 31, 2018
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)		$ 395	$ 395
Disclosure of rate matters, rate base				$ 10,200
Requested rate increase (decrease), amended, amount	$ 396	393
Requested rate increase (decrease), amount amended from initial request		$ (2)
Requested rate increase (decrease), percent			15.00%
Requested rate increase (decrease), percentage, net of tax	15.60%		17.00%

Regulatory Matters (Piedmont Na

Regulatory Matters (Piedmont Narrative) (Details) - Piedmont - USD ($) $ in Millions	Oct. 31, 2019	Aug. 13, 2019	Apr. 01, 2019	Jun. 30, 2019	Nov. 30, 2018
NCUC IMR Petition Filed April 2019 | NCUC
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission				$ 9
NCUC IMR Petition Filed October 2019 | NCUC
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)	$ 11
Tennessee Integrity Management Rider Filing November 2018 | TPUC
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission					$ 4
2019 North Carolina Rate Case | NCUC
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)		$ 83	$ 83
Requested rate increase (decrease), percent			9.00%
Requested return on equity, percentage		9.70%
Requested capital structure, percentage		52.00%
Requested debt structure, percentage		48.00%
Requested gross rate case revenue increase		$ 109
Measurement period adjustments		(23)
Tax benefit from change in enacted tax rates		(37)
North Carolina DOR | State | 2019 North Carolina Rate Case | NCUC
Public Utilities, General Disclosures [Line Items]
Approved increase (decrease) through EDIT Rider		$ (21)

Regulatory Matters (Other Regul

Regulatory Matters (Other Regulatory Matters Narrative) (Details) - USD ($) $ in Millions	Sep. 02, 2014	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Public Utilities, General Disclosures [Line Items]
Investments in equity method unconsolidated affiliates		$ 1,936	$ 1,936	$ 1,409	$ 1,175
Remaining net book value		102,127	102,127	91,694
Atlantic Coast Pipeline (ACP)
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage	47.00%
Supply contract, term	20 years
Estimated capital cost		8,000	8,000
Investments in equity method unconsolidated affiliates		1,200	1,200
Maximum loss exposure, amount		$ 827	$ 827
Atlantic Coast Pipeline (ACP) | Dominion Resources
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage	48.00%
Atlantic Coast Pipeline (ACP) | Southern Company Gas
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage	5.00%
Constitution
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		24.00%	24.00%
OTTI impairment loss		$ 25
Constitution | Williams Partners L.P.
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		41.00%	41.00%
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Remaining net book value		$ 32,397	$ 32,397	29,245
Duke Energy Carolinas | Atlantic Coast Pipeline (ACP)
Public Utilities, General Disclosures [Line Items]
Long-term purchase commitment term	20 years
Duke Energy Progress
Public Utilities, General Disclosures [Line Items]
Remaining net book value		22,934	22,934	20,398
Duke Energy Progress | Atlantic Coast Pipeline (ACP)
Public Utilities, General Disclosures [Line Items]
Long-term purchase commitment term	20 years
Piedmont
Public Utilities, General Disclosures [Line Items]
Investments in equity method unconsolidated affiliates		83	83	64
Remaining net book value		6,765	6,765	$ 5,911
Piedmont | Atlantic Coast Pipeline (ACP)
Public Utilities, General Disclosures [Line Items]
Long-term purchase commitment term	20 years
Generation Facilities Evaluated For Retirement | Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Remaining net book value		721	721
Generation Facilities Evaluated For Retirement | Duke Energy Progress
Public Utilities, General Disclosures [Line Items]
Remaining net book value		$ 1,200	$ 1,200
Financial guarantee | ACP
Public Utilities, General Disclosures [Line Items]
Maximum exposure percentage			47.00%

Regulatory Matters (Schedule _2

Regulatory Matters (Schedule of Net Carrying Value Of Facilities) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)MW	Dec. 31, 2018USD ($)
Public Utilities, General Disclosures [Line Items]
Remaining net book value	$ 102,127	$ 91,694
Piedmont
Public Utilities, General Disclosures [Line Items]
Remaining net book value	6,765	5,911
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Remaining net book value	32,397	29,245
Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Remaining net book value	$ 11,072	$ 10,529
Generating facilities planned for retirement
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	5,002
Remaining net book value	$ 2,937
Generating facilities planned for retirement | Duke Energy Carolinas | Allen Steam Station Units 1-3
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	585
Remaining net book value	$ 152
Generating facilities planned for retirement | Duke Energy Indiana | Gallagher Units 2 and 4
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Remaining net book value	$ 114
Generating facilities planned for retirement | Duke Energy Indiana | Gibson Units 1 - 5
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	3,132
Remaining net book value	$ 1,697
Generating facilities planned for retirement | Duke Energy Indiana | Cayuga Units 1 - 2
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,005
Remaining net book value	$ 974

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Details) $ in Millions	Feb. 11, 2020claim	Jun. 18, 2018USD ($)	Apr. 26, 2017claim	Feb. 28, 2019USD ($)	Dec. 31, 2019USD ($)plantbasinreactorclaim	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)plantbasinreactorclaim	Jun. 13, 2019claim	Dec. 31, 2018USD ($)	May 16, 2017claim
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					98		98
Insured public liability limit per nuclear incident					$ 13,900		$ 13,900
Excess nuclear liability program coverage					13,500		13,500
Pro rata assessment for each reactor owned for each incident exceeding public liability insurance					138		138
Annual payment limit to pro rata assessments					20.5		20.5
Industry aggregate limit					3,200		3,200
Sublimit for non-nuclear terrorist events					1,800		1,800
Sublimit property damage losses					1,500		1,500
Additional nuclear accident limit					$ 1,250		$ 1,250
Insurance coverage percentage initial weeks					100.00%		100.00%
Accidental outage insurance coverage initial weeks							365 days
Insurance coverage percentage additional weeks					80.00%		80.00%
Accidental outage insurance coverage additional weeks							770 days
Weeks of sublimits for accidental outage coverage							728 days
Sublimit accidental outage recovery					$ 328		$ 328
Maximum magnitude of retroactive premiums					10		10
Maximum period for retroactive premium assessment							6 years
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reduction of prior year impairment					$ (14)	$ 25	$ 11
Reserves for legal matters					$ 62		$ 62		$ 65
Coal Ash Insurance Coverage Litigation
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Number of NC and SC plants with ash basins | plant					15		15
NCDEQ State Enforcement Actions
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Number of Plants with No Disputed Facts | plant					7		7
Facilities with ash basins | plant					14		14
Number of Plants with Disputed Facts | plant					7		7
Duke Energy Carolinas
Insurance [Abstract]
Primary nuclear liability program coverage					$ 450		$ 450
Max retroactive premium assessments							155
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					2		2		9
Duke Energy Carolinas | Asbestos Issue
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves					604		604		630
Reinsurance retention policy, excess retention, amount reinsured							747
Loss contingency, receivable, noncurrent					$ 742		$ 742		739
Duke Energy Carolinas | Asbestos Issue | Non Malignant Asbestos Claim
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim					123		123
Asbestos-related injuries and damages reserves					$ 32		$ 32
Duke Energy Carolinas | Asbestos Issue | Malignant Asbestos Claim
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim					49		49
Asbestos-related injuries and damages reserves					$ 16		$ 16
Duke Energy Carolinas | McGuire
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					2		2
Accidental outage insurance coverage policy limit					$ 490		$ 490
Duke Energy Carolinas | Catawba
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					2,000,000		2,000,000
Dedicated additional nuclear accident limit					$ 1,250		$ 1,250
Additional Non-nuclear accident limit					750		750
Accidental outage insurance coverage policy limit					$ 490		$ 490
Potential obligation percentage					100.00%		100.00%
Duke Energy Carolinas | Oconee
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					3		3
Additional Non-nuclear accident limit					$ 750		$ 750
Accidental outage insurance coverage policy limit					$ 406		$ 406
Duke Energy Carolinas and Duke Energy Progress
Insurance [Abstract]
Number of coal ash basins | basin					9		9
Duke Energy Carolinas and Duke Energy Progress | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					7		7
Duke Energy Carolinas and Duke Energy Progress | Allen | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					2		2
Duke Energy Carolinas and Duke Energy Progress | Belews Creek | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					1		1
Duke Energy Carolinas and Duke Energy Progress | Mayo | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					1		1
Duke Energy Carolinas and Duke Energy Progress | Roxboro | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					1		1
Duke Energy Carolinas and Duke Energy Progress | Rogers | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					2		2
Duke Energy Carolinas and Duke Energy Progress | Marshall and Roxboro | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					2		2
Duke Energy Florida
Insurance [Abstract]
Primary nuclear liability program coverage					$ 100		$ 100
Max retroactive premium assessments							1
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					22		22		24
Duke Energy Florida | Spent Nuclear Fuel Matters
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Damages sought		$ 203
Duke Energy Florida | Fluor Letter Of Credit
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Drawings on credit facility				$ 67
Duke Energy Florida | Crystal River Unit 3
Insurance [Abstract]
Sublimit property damage losses					50		50
Duke Energy Florida | Citrus County Combined Cycle Facility
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reduction of prior year impairment							36
Progress Energy
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reduction of prior year impairment					11	$ 25	36
Reserves for legal matters					55		55		54
Duke Energy Progress
Insurance [Abstract]
Primary nuclear liability program coverage					450		450
Max retroactive premium assessments							94
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					$ 12		$ 12		12
Duke Energy Progress | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim										1
Duke Energy Progress | Spent Nuclear Fuel Matters
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Damages sought		$ 100
Duke Energy Progress | Subsequent Event | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Claims Dismissed, Number | claim	3
Duke Energy Progress | Robinson
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					1		1
Accidental outage insurance coverage policy limit					$ 364		$ 364
Duke Energy Progress | Harris
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					1,000,000		1,000,000
Accidental outage insurance coverage policy limit					$ 462		$ 462
Duke Energy Progress | Brunswick
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					2		2
Accidental outage insurance coverage policy limit					$ 462		$ 462
Duke Energy Progress | Mayo | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Claims Dismissed, Number | claim			4
Loss contingency, pending claims, number | claim										2
Duke Energy Progress | Roxboro | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim								2
Piedmont
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					$ 1		$ 1		$ 1

Commitments and Contingencies_3

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 77	$ 81	$ 98
Provision/adjustments	33	26	8
Cash reductions	(52)	(30)	(25)
Ending balance	58	77	81
Duke Energy Carolinas
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	11	10	10
Provision/adjustments	6	3	3
Cash reductions	(6)	(2)	(3)
Ending balance	11	11	10
Progress Energy
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	11	15	18
Provision/adjustments	9	2	3
Cash reductions	(4)	(6)	(6)
Ending balance	16	11	15
Duke Energy Progress
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	4	3	3
Provision/adjustments	2	3	2
Cash reductions	(2)	(2)	(2)
Ending balance	4	4	3
Duke Energy Florida
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	6	12	14
Provision/adjustments	5	(2)	2
Cash reductions	(2)	(4)	(4)
Ending balance	9	6	12
Duke Energy Ohio
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	48	47	59
Provision/adjustments	11	21	3
Cash reductions	(40)	(20)	(15)
Ending balance	19	48	47
Duke Energy Indiana
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	5	5	10
Provision/adjustments		1	(4)
Cash reductions	(1)	(1)	(1)
Ending balance	4	5	5
Piedmont
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	2	2	1
Provision/adjustments	7	1	1
Cash reductions	(1)	(1)
Ending balance	8	$ 2	$ 2
Environmental reserves
Accrual for Environmental Loss Contingencies [Roll Forward]
Additional losses in excess of recorded reserves that could be incurred	59
Environmental reserves | Duke Energy Carolinas
Accrual for Environmental Loss Contingencies [Roll Forward]
Additional losses in excess of recorded reserves that could be incurred	11
Environmental reserves | Duke Energy Ohio
Accrual for Environmental Loss Contingencies [Roll Forward]
Additional losses in excess of recorded reserves that could be incurred	42
Environmental reserves | Piedmont
Accrual for Environmental Loss Contingencies [Roll Forward]
Additional losses in excess of recorded reserves that could be incurred	$ 2

Commitments and Contingencies_4

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Legal Reserves Details [Line Items]
Reserves for legal matters	$ 62	$ 65
Duke Energy Carolinas
Legal Reserves Details [Line Items]
Reserves for legal matters	2	9
Progress Energy
Legal Reserves Details [Line Items]
Reserves for legal matters	55	54
Duke Energy Progress
Legal Reserves Details [Line Items]
Reserves for legal matters	12	12
Duke Energy Florida
Legal Reserves Details [Line Items]
Reserves for legal matters	22	24
Piedmont
Legal Reserves Details [Line Items]
Reserves for legal matters	$ 1	$ 1

Commitments and Contingencies_5

Commitments and Contingencies (Purchased Power) (Details) - Purchased Power Contracts $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Duke Energy Progress
Unconditional Purchase Obligations [Abstract]
2020	$ 46
2021	66
2022	63
2023	55
2024	56
Thereafter	123
Total	$ 409
Duke Energy Progress | Maximum
Unconditional Purchase Obligations [Abstract]
Net plant output percent	100.00%
Duke Energy Florida
Unconditional Purchase Obligations [Abstract]
2020	$ 374
2021	356
2022	354
2023	374
2024	262
Thereafter	91
Total	$ 1,811
Duke Energy Florida | Minimum
Unconditional Purchase Obligations [Abstract]
Net plant output percent	81.00%
Duke Energy Florida | Maximum
Unconditional Purchase Obligations [Abstract]
Net plant output percent	100.00%
Duke Energy Ohio
Unconditional Purchase Obligations [Abstract]
2020	$ 132
2021	107
2022	32
Total	$ 271
Duke Energy Ohio | Minimum
Unconditional Purchase Obligations [Abstract]
Net plant output percent	1.00%
Duke Energy Ohio | Maximum
Unconditional Purchase Obligations [Abstract]
Net plant output percent	9.00%

Commitments and Contingencies_6

Commitments and Contingencies (Gas Supply Contracts) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Natural Gas Supply and Capacity Contracts
Long-term Purchase Commitment [Line Items]
2020	$ 297
2021	280
2022	225
2023	129
2024	118
Thereafter	714
Total	$ 1,763
Maximum | Pipeline and storage capacity contracts
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment term	15 years
Maximum | Natural gas supply contracts fixed payment
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment term	6 years
Maximum | Natural gas supply purchase commitments
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment term	11 years
Duke Energy Ohio | Natural Gas Supply and Capacity Contracts
Long-term Purchase Commitment [Line Items]
2020	$ 39
2021	33
2022	14
2023	3
Total	89
Piedmont | Natural Gas Supply and Capacity Contracts
Long-term Purchase Commitment [Line Items]
2020	258
2021	247
2022	211
2023	126
2024	118
Thereafter	714
Total	$ 1,674

Leases (Operating Lease Right-o

Leases (Operating Lease Right-of-use Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
ROU assets	$ 1,658	$ 1,750
Operating lease liabilities – current	208	205
Operating lease liabilities – noncurrent	1,432	1,504
Duke Energy Carolinas
Lessee, Lease, Description [Line Items]
ROU assets	123	153
Operating lease liabilities – current	27	28
Operating lease liabilities – noncurrent	102	127
Progress Energy
Lessee, Lease, Description [Line Items]
ROU assets	788	863
Operating lease liabilities – current	95	96
Operating lease liabilities – noncurrent	697	766
Duke Energy Progress
Lessee, Lease, Description [Line Items]
ROU assets	387	407
Operating lease liabilities – current	37	35
Operating lease liabilities – noncurrent	354	371
Duke Energy Florida
Lessee, Lease, Description [Line Items]
ROU assets	401	456
Operating lease liabilities – current	58	61
Operating lease liabilities – noncurrent	343	395
Duke Energy Ohio
Lessee, Lease, Description [Line Items]
ROU assets	21	23
Operating lease liabilities – current	1	1
Operating lease liabilities – noncurrent	21	22
Duke Energy Indiana
Lessee, Lease, Description [Line Items]
ROU assets	57	61
Operating lease liabilities – current	3	4
Operating lease liabilities – noncurrent	55	58
Piedmont
Lessee, Lease, Description [Line Items]
ROU assets	24	26
Operating lease liabilities – current	4	4
Operating lease liabilities – noncurrent	$ 23	$ 25

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Operating lease assets, cost basis	$ 147,654	$ 134,458
Piedmont
Lessee, Lease, Description [Line Items]
Operating lease assets, cost basis	8,446	7,486
Construction and transportation of natural gas pipelines | Piedmont
Lessee, Lease, Description [Line Items]
Net Investment in Lease, Current	4
Renewable energy projects
Lessee, Lease, Description [Line Items]
Contingent lease payments	264	268	$ 262
Operating lease assets, cost basis	3,349	3,358
Operating lease assets, accumulated depreciation	721	$ 602
Duke Energy Carolinas | Construction and transportation of natural gas pipelines | Piedmont
Lessee, Lease, Description [Line Items]
Net Investment in Lease, Noncurrent	$ 70

Leases (Lease Costs) (Details)

Leases (Lease Costs) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 292
Short-term lease expense	16
Variable lease expense	47
Finance lease expense
Amortization of leased assets	111
Interest on lease liabilities	61
Total finance lease expense	172
Total lease expense	527
Duke Energy Carolinas
Lessee, Lease, Description [Line Items]
Operating lease expense	47
Short-term lease expense	5
Variable lease expense	22
Finance lease expense
Amortization of leased assets	6
Interest on lease liabilities	15
Total finance lease expense	21
Total lease expense	95
Progress Energy
Lessee, Lease, Description [Line Items]
Operating lease expense	161
Short-term lease expense	9
Variable lease expense	22
Finance lease expense
Amortization of leased assets	21
Interest on lease liabilities	42
Total finance lease expense	63
Total lease expense	255
Duke Energy Progress
Lessee, Lease, Description [Line Items]
Operating lease expense	69
Short-term lease expense	4
Variable lease expense	16
Finance lease expense
Amortization of leased assets	5
Interest on lease liabilities	33
Total finance lease expense	38
Total lease expense	127
Duke Energy Florida
Lessee, Lease, Description [Line Items]
Operating lease expense	92
Short-term lease expense	5
Variable lease expense	6
Finance lease expense
Amortization of leased assets	16
Interest on lease liabilities	9
Total finance lease expense	25
Total lease expense	128
Duke Energy Ohio
Lessee, Lease, Description [Line Items]
Operating lease expense	11
Short-term lease expense	1
Finance lease expense
Amortization of leased assets	1
Total finance lease expense	1
Total lease expense	13
Duke Energy Indiana
Lessee, Lease, Description [Line Items]
Operating lease expense	20
Short-term lease expense	2
Variable lease expense	1
Finance lease expense
Interest on lease liabilities	1
Total finance lease expense	1
Total lease expense	24
Piedmont
Lessee, Lease, Description [Line Items]
Operating lease expense	5
Variable lease expense	1
Finance lease expense
Total lease expense	$ 6

Leases (Rent Expense) (Details)

Leases (Rent Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating Leased Assets [Line Items]
Rental expense on operating leases	$ 268	$ 241
Duke Energy Carolinas
Operating Leased Assets [Line Items]
Rental expense on operating leases	49	44
Progress Energy
Operating Leased Assets [Line Items]
Rental expense on operating leases	143	130
Duke Energy Progress
Operating Leased Assets [Line Items]
Rental expense on operating leases	75	75
Duke Energy Florida
Operating Leased Assets [Line Items]
Rental expense on operating leases	68	55
Duke Energy Ohio
Operating Leased Assets [Line Items]
Rental expense on operating leases	13	15
Duke Energy Indiana
Operating Leased Assets [Line Items]
Rental expense on operating leases	21	23
Piedmont
Operating Leased Assets [Line Items]
Rental expense on operating leases	$ 11	$ 7

Leases (Operating Lease Maturit

Leases (Operating Lease Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due (Topic 842)
2020	$ 268
2021	216
2022	201
2023	191
2024	176
Thereafter	984
Total operating lease payments	2,036
Less: present value discount	(396)
Total operating lease liabilities	1,640
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		$ 239
2020		219
2021		186
2022		170
2023		160
Thereafter		1,017
Total		1,991
Duke Energy Carolinas
Operating Lease Liabilities, Payments Due (Topic 842)
2020	31
2021	19
2022	19
2023	17
2024	13
Thereafter	57
Total operating lease payments	156
Less: present value discount	(27)
Total operating lease liabilities	129
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		33
2020		29
2021		19
2022		19
2023		17
Thereafter		68
Total		185
Progress Energy
Operating Lease Liabilities, Payments Due (Topic 842)
2020	123
2021	99
2022	95
2023	95
2024	95
Thereafter	462
Total operating lease payments	969
Less: present value discount	(177)
Total operating lease liabilities	792
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		97
2020		90
2021		79
2022		76
2023		77
Thereafter		455
Total		874
Duke Energy Progress
Operating Lease Liabilities, Payments Due (Topic 842)
2020	51
2021	44
2022	40
2023	41
2024	41
Thereafter	283
Total operating lease payments	500
Less: present value discount	(109)
Total operating lease liabilities	391
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		49
2020		46
2021		37
2022		34
2023		35
Thereafter		314
Total		515
Duke Energy Florida
Operating Lease Liabilities, Payments Due (Topic 842)
2020	72
2021	55
2022	55
2023	54
2024	54
Thereafter	179
Total operating lease payments	469
Less: present value discount	(68)
Total operating lease liabilities	401
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		48
2020		44
2021		42
2022		42
2023		42
Thereafter		141
Total		359
Duke Energy Ohio
Operating Lease Liabilities, Payments Due (Topic 842)
2020	2
2021	2
2022	2
2023	2
2024	2
Thereafter	21
Total operating lease payments	31
Less: present value discount	(9)
Total operating lease liabilities	22
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		2
2020		2
2021		2
2022		2
2023		2
Thereafter		23
Total		33
Duke Energy Indiana
Operating Lease Liabilities, Payments Due (Topic 842)
2020	5
2021	4
2022	4
2023	4
2024	4
Thereafter	64
Total operating lease payments	85
Less: present value discount	(27)
Total operating lease liabilities	58
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		6
2020		5
2021		4
2022		4
2023		5
Thereafter		66
Total		90
Piedmont
Operating Lease Liabilities, Payments Due (Topic 842)
2020	5
2021	5
2022	5
2023	5
2024	5
Thereafter	5
Total operating lease payments	30
Less: present value discount	(3)
Total operating lease liabilities	$ 27
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		5
2020		5
2021		5
2022		5
2023		6
Thereafter		11
Total		$ 37

Leases (Finance Lease Maturitie

Leases (Finance Lease Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	$ 181
2021	186
2022	173
2023	175
2024	121
Thereafter	823
Total finance lease payments	1,659
Less: amounts representing interest	(690)
Total finance lease liabilities	969
Finance Lease Liabilities, Payments Due (Topic 840)
2019		$ 170
2020		174
2021		177
2022		165
2023		165
Thereafter		577
Minimum annual payments		1,428
Less: amount representing interest		(487)
Total		941
Duke Energy Carolinas
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	28
2021	23
2022	23
2023	23
2024	23
Thereafter	314
Total finance lease payments	434
Less: amounts representing interest	(255)
Total finance lease liabilities	179
Finance Lease Liabilities, Payments Due (Topic 840)
2019		20
2020		20
2021		15
2022		15
2023		15
Thereafter		204
Minimum annual payments		289
Less: amount representing interest		(180)
Total		109
Progress Energy
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	69
2021	69
2022	69
2023	69
2024	55
Thereafter	539
Total finance lease payments	870
Less: amounts representing interest	(465)
Total finance lease liabilities	405
Finance Lease Liabilities, Payments Due (Topic 840)
2019		45
2020		46
2021		45
2022		45
2023		45
Thereafter		230
Minimum annual payments		456
Less: amount representing interest		(205)
Total		251
Duke Energy Progress
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	44
2021	44
2022	44
2023	44
2024	44
Thereafter	528
Total finance lease payments	748
Less: amounts representing interest	(441)
Total finance lease liabilities	307
Finance Lease Liabilities, Payments Due (Topic 840)
2019		20
2020		21
2021		20
2022		21
2023		21
Thereafter		209
Minimum annual payments		312
Less: amount representing interest		(175)
Total		137
Duke Energy Florida
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	25
2021	25
2022	25
2023	25
2024	11
Thereafter	11
Total finance lease payments	122
Less: amounts representing interest	(24)
Total finance lease liabilities	98
Finance Lease Liabilities, Payments Due (Topic 840)
2019		25
2020		25
2021		25
2022		24
2023		24
Thereafter		21
Minimum annual payments		144
Less: amount representing interest		(30)
Total		114
Duke Energy Ohio
Finance Lease Liabilities, Payments Due (Topic 840)
2019		2
Minimum annual payments		2
Total		2
Duke Energy Indiana
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	1
2021	1
2022	1
2023	1
2024	1
Thereafter	27
Total finance lease payments	32
Less: amounts representing interest	(22)
Total finance lease liabilities	$ 10
Finance Lease Liabilities, Payments Due (Topic 840)
2019		1
2020		1
2021		1
2022		1
2023		1
Thereafter		27
Minimum annual payments		32
Less: amount representing interest		(22)
Total		$ 10

Leases (Supplemental Financial

Leases (Supplemental Financial Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019
Assets
ROU assets	$ 1,658	$ 1,750
Finance	926
Total lease assets	2,584
Current
Operating	208	205
Finance	119
Noncurrent
Operating lease liabilities	1,432	1,504
Finance	850
Total lease liabilities	2,609
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	285
Operating cash flows from finance leases	61
Financing cash flows from finance leases	111
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	194
Finance	$ 251
Weighted-average remaining lease term (years)
Operating leases	11 years
Finance leases	13 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	8.10%
Duke Energy Carolinas
Assets
ROU assets	$ 123	153
Finance	198
Total lease assets	321
Current
Operating	27	28
Finance	7
Noncurrent
Operating lease liabilities	102	127
Finance	172
Total lease liabilities	308
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	34
Operating cash flows from finance leases	15
Financing cash flows from finance leases	6
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	44
Finance	$ 76
Weighted-average remaining lease term (years)
Operating leases	9 years
Finance leases	19 years
Weighted-average discount rate
Operating leases	3.50%
Finance leases	11.80%
Progress Energy
Assets
ROU assets	$ 788	863
Finance	443
Total lease assets	1,231
Current
Operating	95	96
Finance	24
Noncurrent
Operating lease liabilities	697	766
Finance	381
Total lease liabilities	1,197
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	131
Operating cash flows from finance leases	42
Financing cash flows from finance leases	21
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	30
Finance	$ 175
Weighted-average remaining lease term (years)
Operating leases	10 years
Finance leases	16 years
Weighted-average discount rate
Operating leases	3.80%
Finance leases	11.90%
Duke Energy Progress
Assets
ROU assets	$ 387	407
Finance	308
Total lease assets	695
Current
Operating	37	35
Finance	6
Noncurrent
Operating lease liabilities	354	371
Finance	301
Total lease liabilities	698
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	53
Operating cash flows from finance leases	33
Financing cash flows from finance leases	5
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	30
Finance	$ 175
Weighted-average remaining lease term (years)
Operating leases	12 years
Finance leases	18 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	12.40%
Duke Energy Florida
Assets
ROU assets	$ 401	456
Finance	135
Total lease assets	536
Current
Operating	58	61
Finance	18
Noncurrent
Operating lease liabilities	343	395
Finance	80
Total lease liabilities	499
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	78
Operating cash flows from finance leases	9
Financing cash flows from finance leases	$ 16
Weighted-average remaining lease term (years)
Operating leases	8 years
Finance leases	11 years
Weighted-average discount rate
Operating leases	3.80%
Finance leases	8.30%
Duke Energy Ohio
Assets
ROU assets	$ 21	23
Total lease assets	21
Current
Operating	1	1
Noncurrent
Operating lease liabilities	21	22
Total lease liabilities	22
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	2
Financing cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	17 years
Weighted-average discount rate
Operating leases	4.20%
Finance leases	0.00%
Duke Energy Indiana
Assets
ROU assets	$ 57	61
Finance	7
Total lease assets	64
Current
Operating	3	4
Noncurrent
Operating lease liabilities	55	58
Finance	10
Total lease liabilities	68
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	7
Operating cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	18 years
Finance leases	26 years
Weighted-average discount rate
Operating leases	4.10%
Finance leases	11.90%
Piedmont
Assets
ROU assets	$ 24	26
Total lease assets	24
Current
Operating	4	4
Noncurrent
Operating lease liabilities	23	$ 25
Total lease liabilities	27
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	7
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	$ 1
Weighted-average remaining lease term (years)
Operating leases	6 years
Weighted-average discount rate
Operating leases	3.60%
Finance leases	0.00%

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt and Related Terms) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Weighted-average rate	3.92%	4.13%
Unsecured Debt	$ 22,477	$ 20,955
Secured Debt	4,537	4,297
First mortgage bonds	27,977	25,628
Finance leases	969
Finance leases		941
Tax exempt bonds	730	941
Notes payable and commercial paper	3,588	4,035
Fair value hedge carrying value adjustment	5	5
Unamortized debt discount and premium, net	1,294	1,434
Unamortized debt issuance costs	(316)	(297)
Total debt	61,261	57,939
Short-term notes payable and commercial paper	(3,135)	(3,410)
Current maturities of long-term debt	(3,141)	(3,406)
Total long-term debt	54,985	51,123
Short term obligations classified as long-term debt	$ 937	$ 937
Unsecured Debt
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2020	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2078	Dec. 31, 2078
Weighted-average rate	4.02%	4.26%
Secured Debt
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2020	Dec. 31, 2020
Maturity date range, end	Dec. 31, 2052	Dec. 31, 2037
Weighted-average rate	3.30%	3.69%
First Mortgage
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2020	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2049	Dec. 31, 2048
Weighted-average rate	4.13%	4.32%
Capital Lease Obligations
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2022	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2051	Dec. 31, 2051
Weighted-average rate	6.60%	5.06%
Tax Exempt Bonds
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2022	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2041	Dec. 31, 2041
Weighted-average rate	2.90%	3.40%
Short term obligations classified as long-term debt	$ 312	$ 312
Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	$ 625	$ 625
Notes Payable And Commercial Paper
Debt Instrument [Line Items]
Weighted-average rate	1.98%	2.73%
Short term obligations classified as long-term debt	$ 625	$ 625
Weighted average days to maturity	14 days	16 days
Parent Company | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 37	$ 41
Duke Energy Carolinas
Debt Instrument [Line Items]
Unsecured Debt	1,150	1,150
Secured Debt	544	450
First mortgage bonds	9,557	8,759
Finance leases	179
Finance leases		109
Tax exempt bonds	243	243
Money pool/intercompany borrowings	329	739
Fair value hedge carrying value adjustment	5	5
Unamortized debt discount and premium, net	(23)	(23)
Unamortized debt issuance costs	(55)	(54)
Total debt	11,929	11,378
Short-term money pool/intercompany borrowings	(29)	(439)
Current maturities of long-term debt	(458)	(6)
Total long-term debt	11,442	10,933
Short term obligations classified as long-term debt	300	300
Duke Energy Carolinas | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300	300
Progress Energy
Debt Instrument [Line Items]
Unsecured Debt	3,650	3,800
Secured Debt	1,722	1,703
First mortgage bonds	13,800	13,100
Finance leases	405
Finance leases		251
Tax exempt bonds	48	48
Money pool/intercompany borrowings	1,970	1,385
Unamortized debt discount and premium, net	(29)	(29)
Unamortized debt issuance costs	(111)	(112)
Total debt	21,455	20,146
Short-term money pool/intercompany borrowings	(1,821)	(1,235)
Current maturities of long-term debt	(1,577)	(1,672)
Total long-term debt	18,057	17,239
Duke Energy Progress
Debt Instrument [Line Items]
Unsecured Debt	700	50
Secured Debt	335	300
First mortgage bonds	7,575	7,574
Finance leases	307
Finance leases		137
Tax exempt bonds	48	48
Money pool/intercompany borrowings	216	444
Unamortized debt discount and premium, net	(17)	(15)
Unamortized debt issuance costs	(40)	(40)
Total debt	9,124	8,498
Short-term money pool/intercompany borrowings	(66)	(294)
Current maturities of long-term debt	(1,006)	(603)
Total long-term debt	8,052	7,601
Short term obligations classified as long-term debt	150	150
Duke Energy Progress | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Duke Energy Progress | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Finance leases	44
Finance leases		63
Duke Energy Florida
Debt Instrument [Line Items]
Unsecured Debt	350	350
Secured Debt	1,387	1,403
First mortgage bonds	6,225	5,526
Finance leases	98
Finance leases		114
Money pool/intercompany borrowings		108
Unamortized debt discount and premium, net	(11)	(11)
Unamortized debt issuance costs	(62)	(61)
Total debt	7,987	7,429
Short-term money pool/intercompany borrowings		(108)
Current maturities of long-term debt	(571)	(270)
Total long-term debt	7,416	7,051
Duke Energy Florida | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Finance leases	419
Finance leases		531
Duke Energy Ohio
Debt Instrument [Line Items]
Unsecured Debt	1,110	1,000
First mortgage bonds	1,449	1,099
Finance leases		2
Tax exempt bonds	77	77
Money pool/intercompany borrowings	337	299
Unamortized debt discount and premium, net	(30)	(31)
Unamortized debt issuance costs	(12)	(7)
Total debt	2,931	2,439
Short-term money pool/intercompany borrowings	(312)	(274)
Current maturities of long-term debt		(551)
Total long-term debt	2,619	1,614
Short term obligations classified as long-term debt	52	52
Duke Energy Ohio | Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	27	27
Duke Energy Ohio | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	25	25
Duke Energy Indiana
Debt Instrument [Line Items]
Unsecured Debt	405	408
First mortgage bonds	3,169	2,670
Finance leases	10
Finance leases		10
Tax exempt bonds	362	572
Money pool/intercompany borrowings	180	317
Unamortized debt discount and premium, net	(19)	(8)
Unamortized debt issuance costs	(20)	(20)
Total debt	4,087	3,949
Short-term money pool/intercompany borrowings	(30)	(167)
Current maturities of long-term debt	(503)	(63)
Total long-term debt	3,554	3,719
Short term obligations classified as long-term debt	435	435
Duke Energy Indiana | Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	285	285
Duke Energy Indiana | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Piedmont
Debt Instrument [Line Items]
Unsecured Debt	2,399	2,150
Money pool/intercompany borrowings	476	198
Unamortized debt discount and premium, net	(2)	(1)
Unamortized debt issuance costs	(13)	(11)
Total debt	2,860	2,336
Short-term money pool/intercompany borrowings	(476)	(198)
Current maturities of long-term debt		(350)
Total long-term debt	2,384	1,788
Progress Energy | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	1,275	1,380
Piedmont | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	$ 137	$ 156

Debt and Credit Facilities (Ann

Debt and Credit Facilities (Annual Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	$ 3,141	$ 3,406
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	3,141
2021	5,053
2022	4,334
2023	3,112
2024	1,965
Thereafter	39,542
Total long-term debt, including current maturities	57,147
Purchase accounting adjustments	(1,500)	(1,600)
Other
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	361
Purchase Accounting Adjustments
Long-term Debt, Fiscal Year Maturity [Abstract]
Purchase accounting adjustments	$ 1,448
Parent Company | Debt Maturing June 2020, 2.100% Coupon | Unsecured Debt
Current Maturities Of Long Term Debt [Abstract]
Interest rate	2.10%
Current maturities of long-term debt	$ 330
Duke Energy Carolinas
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	458	6
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	458
2021	504
2022	830
2023	1,006
2024	306
Thereafter	8,875
Total long-term debt, including current maturities	$ 11,979
Duke Energy Carolinas | Bonds Maturing June 2020, 4.300% Coupon | First Mortgage
Current Maturities Of Long Term Debt [Abstract]
Interest rate	4.30%
Current maturities of long-term debt	$ 450
Progress Energy
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	1,577	1,672
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	1,578
2021	2,257
2022	1,048
2023	398
2024	227
Thereafter	14,267
Total long-term debt, including current maturities	19,775
Duke Energy Progress
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	1,006	603
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	1,006
2021	932
2022	508
2023	319
2024	160
Thereafter	6,190
Total long-term debt, including current maturities	$ 9,115
Duke Energy Progress | Bonds Maturing September 2020, 2.282% Coupon | First Mortgage
Current Maturities Of Long Term Debt [Abstract]
Interest rate	2.065%
Current maturities of long-term debt	$ 300
Duke Energy Progress | Parent Company | Debt Maturing December 2020, 2.510% Coupon | Unsecured Debt
Current Maturities Of Long Term Debt [Abstract]
Interest rate	2.51%
Current maturities of long-term debt	$ 700
Duke Energy Florida
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	571	270
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	572
2021	825
2022	90
2023	79
2024	67
Thereafter	6,427
Total long-term debt, including current maturities	$ 8,060
Duke Energy Florida | Bonds Maturing January 2019, 5.300% Coupon | First Mortgage
Current Maturities Of Long Term Debt [Abstract]
Interest rate	1.85%
Current maturities of long-term debt	$ 250
Duke Energy Florida | Bonds Maturing April 2019, 5.450% Coupon | First Mortgage
Current Maturities Of Long Term Debt [Abstract]
Interest rate	4.55%
Current maturities of long-term debt	$ 250
Duke Energy Ohio
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt		551
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	0
2021	50
2022	0
2023	325
2024	25
Thereafter	2,261
Total long-term debt, including current maturities	2,661
Duke Energy Indiana
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	503	63
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	503
2021	70
2022	94
2023	3
2024	154
Thereafter	3,272
Total long-term debt, including current maturities	$ 4,096
Duke Energy Indiana | Bonds Maturing July 2020, 3.750% Coupon | First Mortgage
Current Maturities Of Long Term Debt [Abstract]
Interest rate	3.75%
Current maturities of long-term debt	$ 500
Piedmont
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt		$ 350
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	0
2021	160
2022	0
2023	45
2024	40
Thereafter	2,155
Total long-term debt, including current maturities	$ 2,400

Debt and Credit Facilities (Sho

Debt and Credit Facilities (Short Term Obligations Classified As Long Term) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	$ 937	$ 937
Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	312	312
Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	625	625
Duke Energy Carolinas
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300	300
Duke Energy Carolinas | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300	300
Duke Energy Progress
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Duke Energy Progress | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Duke Energy Ohio
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	52	52
Duke Energy Ohio | Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	27	27
Duke Energy Ohio | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	25	25
Duke Energy Indiana
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	435	435
Duke Energy Indiana | Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	285	285
Duke Energy Indiana | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	$ 150	$ 150

Debt and Credit Facilities (S_2

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt issuances	$ 6,210,000,000	$ 5,050,000,000
Redemption of long-term debt	$ 3,476,000,000	$ 2,906,000,000	$ 2,316,000,000
March 2019 Debt Issuance Due March 2022 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	2.538%
Debt issuances	$ 300,000,000
March 2019 Debt Issuance 3.227% Coupon Due 2022 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	3.227%
Debt issuances	$ 300,000,000
May 2019 Debt Issuance 3.500% Coupon Due 2029 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	3.50%
Debt issuances	$ 600,000,000
June 2019 Debt Issuance 3.400% Coupon Due 2029 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	3.40%
Debt issuances	$ 600,000,000
June 2019 Debt Issuance 4.200% Coupon Due 2049 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	4.20%
Debt issuances	$ 600,000,000
July 2019 Debt Issuance 4.320% Coupon Due 2049 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	4.32%
Debt issuances	$ 40,000,000
September 2019 Debt Issuance 3.230% Coupon Due 2025 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	3.23%
Debt issuances	$ 95,000,000
September 2019 Debt Issuance 3.560% Coupon Due 2029 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	3.56%
Debt issuances	$ 75,000,000
November 2019 Debt Issuance 2.167% Coupon Due 2021 | Unsecured Debt
Debt Instrument [Line Items]
Interest rate	2.167%
Debt issuances	$ 200,000,000
January 2019 Debt Issuance 3.650% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Interest rate	3.65%
Debt issuances	$ 400,000,000
January 2019 Debt Issuance 4.300% Coupon Due 2049 | First Mortgage
Debt Instrument [Line Items]
Interest rate	4.30%
Debt issuances	$ 400,000,000
March 2019 Debt Issuance 3.450% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Interest rate	3.45%
Debt issuances	$ 600,000,000
August 2019 Debt Issuance 2.450% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Interest rate	2.45%
Debt issuances	$ 450,000,000
August 2019 Debt Issuance 3.200% Coupon Due 2049 | First Mortgage
Debt Instrument [Line Items]
Interest rate	3.20%
Debt issuances	$ 350,000,000
September 2019 Debt Issuance 3.250% Coupon Due 2049 | First Mortgage
Debt Instrument [Line Items]
Interest rate	3.25%
Debt issuances	$ 500,000,000
November 2019 Debt Issuance 2.500% Coupon Due 2029
Debt Instrument [Line Items]
Interest rate	2.50%
November 2019 Debt Issuance 2.500% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	$ 700,000,000
March 2018 Debt Issuance 3.950% Coupon Due 2025
Debt Instrument [Line Items]
Interest rate		3.95%
March 2018 Debt Issuance 3.950% Coupon Due 2025 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances		$ 250,000,000
May 2018 Debt Issuance 3.114% Coupon Due 2021
Debt Instrument [Line Items]
Interest rate		3.114%
May 2018 Debt Issuance 3.114% Coupon Due 2021 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
September 2018 Debt Issuance 5.625% Coupon Due 2078
Debt Instrument [Line Items]
Interest rate		5.625%
September 2018 Debt Issuance 5.625% Coupon Due 2078 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
March 2018 Debt Issuance 3.050% Coupon Due 2023
Debt Instrument [Line Items]
Interest rate		3.05%
March 2018 Debt Issuance 3.050% Coupon Due 2023 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
March 2018 Debt Issuance 3.950% Coupon Due 2048
Debt Instrument [Line Items]
Interest rate		3.95%
March 2018 Debt Issuance 3.950% Coupon Due 2048 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
June 2018 Debt issuance 3.80% coupon Due 2028
Debt Instrument [Line Items]
Interest rate		3.80%
June 2018 Debt issuance 3.80% coupon Due 2028 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 600,000,000
June 2018 Debt Issuance 4.20 Coupon Due 2048
Debt Instrument [Line Items]
Interest rate		4.20%
June 2018 Debt Issuance 4.20 Coupon Due 2048 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 400,000,000
August 2018 Debt Issuance 3.375% Coupon Due 2023
Debt Instrument [Line Items]
Interest rate		3.375%
August 2018 Debt Issuance 3.375% Coupon Due 2023 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 300,000,000
August 2018 Debt Issuance 3.700% Coupon Due 2028
Debt Instrument [Line Items]
Interest rate		3.70%
August 2018 Debt Issuance 3.700% Coupon Due 2028 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
November 2018 Debt Issuance 3.350% Coupon Due 2022
Debt Instrument [Line Items]
Interest rate		3.35%
November 2018 Debt Issuance 3.350% Coupon Due 2022 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 350,000,000
November 2018 Debt Issuance 3.950% Coupon Due 2028
Debt Instrument [Line Items]
Interest rate		3.95%
November 2018 Debt Issuance 3.950% Coupon Due 2028 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		$ 650,000,000
Parent Company
Debt Instrument [Line Items]
Debt issuances	1,800,000,000	1,250,000,000
Parent Company | March 2019 Debt Issuance Due March 2022 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	300,000,000
Parent Company | March 2019 Debt Issuance 3.227% Coupon Due 2022 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	300,000,000
Parent Company | June 2019 Debt Issuance 3.400% Coupon Due 2029 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	600,000,000
Parent Company | June 2019 Debt Issuance 4.200% Coupon Due 2049 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	600,000,000
Parent Company | March 2018 Debt Issuance 3.950% Coupon Due 2025 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances		250,000,000
Parent Company | May 2018 Debt Issuance 3.114% Coupon Due 2021 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances		500,000,000
Parent Company | September 2018 Debt Issuance 5.625% Coupon Due 2078 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances		500,000,000
Duke Energy Carolinas
Debt Instrument [Line Items]
Debt issuances	800,000,000	2,000,000,000
Redemption of long-term debt	6,000,000	1,205,000,000	116,000,000
Duke Energy Carolinas | First Mortgage
Debt Instrument [Line Items]
Debt issuances		350,000,000
Duke Energy Carolinas | August 2019 Debt Issuance 2.450% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	450,000,000
Duke Energy Carolinas | August 2019 Debt Issuance 3.200% Coupon Due 2049 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	350,000,000
Duke Energy Carolinas | March 2018 Debt Issuance 3.050% Coupon Due 2023 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		500,000,000
Duke Energy Carolinas | March 2018 Debt Issuance 3.950% Coupon Due 2048 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		500,000,000
Duke Energy Carolinas | November 2018 Debt Issuance 3.950% Coupon Due 2028 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		650,000,000
Duke Energy Carolinas | First Mortgage Bonds Maturing April 2018, 5.100% Coupon
Debt Instrument [Line Items]
Repayments of debt		300,000,000
Duke Energy Progress
Debt Instrument [Line Items]
Debt issuances	600,000,000	800,000,000
Redemption of long-term debt	605,000,000	3,000,000	470,000,000
Duke Energy Progress | March 2019 Debt Issuance 3.450% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	600,000,000
Duke Energy Progress | August 2018 Debt Issuance 3.375% Coupon Due 2023 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		300,000,000
Duke Energy Progress | August 2018 Debt Issuance 3.700% Coupon Due 2028 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		500,000,000
Duke Energy Florida
Debt Instrument [Line Items]
Debt issuances	900,000,000	1,000,000,000
Redemption of long-term debt	262,000,000	769,000,000	342,000,000
Duke Energy Florida | November 2019 Debt Issuance 2.167% Coupon Due 2021 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	200,000,000
Duke Energy Florida | March 2019 Debt Issuance 3.450% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	0
Duke Energy Florida | November 2019 Debt Issuance 2.500% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	700,000,000
Duke Energy Florida | June 2018 Debt issuance 3.80% coupon Due 2028 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		600,000,000
Duke Energy Florida | June 2018 Debt Issuance 4.20 Coupon Due 2048 | First Mortgage
Debt Instrument [Line Items]
Debt issuances		400,000,000
Duke Energy Ohio
Debt Instrument [Line Items]
Debt issuances	1,010,000,000
Redemption of long-term debt	551,000,000	3,000,000	2,000,000
Duke Energy Ohio | July 2019 Debt Issuance 4.320% Coupon Due 2049 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	40,000,000
Duke Energy Ohio | September 2019 Debt Issuance 3.230% Coupon Due 2025 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	95,000,000
Duke Energy Ohio | September 2019 Debt Issuance 3.560% Coupon Due 2029 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	75,000,000
Duke Energy Ohio | January 2019 Debt Issuance 3.650% Coupon Due 2029 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	400,000,000
Duke Energy Ohio | January 2019 Debt Issuance 4.300% Coupon Due 2049 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	400,000,000
Duke Energy Ohio | April 2019 First Mortgage Bonds
Debt Instrument [Line Items]
Redemption of long-term debt	450,000,000
Duke Energy Ohio | Debentures Due October 2019
Debt Instrument [Line Items]
Redemption of long-term debt	100,000,000
Duke Energy Indiana
Debt Instrument [Line Items]
Debt issuances	500,000,000
Redemption of long-term debt	213,000,000	$ 3,000,000	5,000,000
Duke Energy Indiana | September 2019 Debt Issuance 3.250% Coupon Due 2049 | First Mortgage
Debt Instrument [Line Items]
Debt issuances	500,000,000
Duke Energy Indiana | Pollution Control Bonds
Debt Instrument [Line Items]
Redemption of long-term debt	150,000,000
Piedmont
Debt Instrument [Line Items]
Debt issuances	600,000,000
Redemption of long-term debt	350,000,000		$ 35,000,000
Piedmont | May 2019 Debt Issuance 3.500% Coupon Due 2029 | Unsecured Debt
Debt Instrument [Line Items]
Debt issuances	600,000,000
Piedmont | Senior Unsecured Term Loan Facility Due September 2019
Debt Instrument [Line Items]
Redemption of long-term debt	$ 350,000,000

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Tax-exempt bonds	$ (730,000,000)	$ (941,000,000)
Duke Energy Carolinas
Line of Credit Facility [Line Items]
Tax-exempt bonds	(243,000,000)	(243,000,000)
Duke Energy Progress
Line of Credit Facility [Line Items]
Tax-exempt bonds	(48,000,000)	(48,000,000)
Duke Energy Ohio
Line of Credit Facility [Line Items]
Tax-exempt bonds	(77,000,000)	(77,000,000)
Duke Energy Indiana
Line of Credit Facility [Line Items]
Tax-exempt bonds	(362,000,000)	$ (572,000,000)
Revolving Credit Facility
Line of Credit Facility [Line Items]
Facility Size	8,000,000,000
Commercial Paper	(2,537,000,000)
Outstanding letters of credit	(50,000,000)
Tax-exempt bonds	(81,000,000)
Coal ash set-aside	(500,000,000)
Available capacity	4,832,000,000
Revolving Credit Facility | Parent Company
Line of Credit Facility [Line Items]
Facility Size	2,650,000,000
Commercial Paper	(1,119,000,000)
Outstanding letters of credit	(42,000,000)
Available capacity	1,489,000,000
Revolving Credit Facility | Duke Energy Carolinas
Line of Credit Facility [Line Items]
Facility Size	1,500,000,000
Commercial Paper	(325,000,000)
Outstanding letters of credit	(4,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	921,000,000
Revolving Credit Facility | Duke Energy Progress
Line of Credit Facility [Line Items]
Facility Size	1,250,000,000
Commercial Paper	(207,000,000)
Outstanding letters of credit	(2,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	791,000,000
Revolving Credit Facility | Duke Energy Florida
Line of Credit Facility [Line Items]
Facility Size	800,000,000
Available capacity	800,000,000
Revolving Credit Facility | Duke Energy Ohio
Line of Credit Facility [Line Items]
Facility Size	600,000,000
Commercial Paper	(296,000,000)
Available capacity	304,000,000
Revolving Credit Facility | Duke Energy Indiana
Line of Credit Facility [Line Items]
Facility Size	600,000,000
Commercial Paper	(176,000,000)
Tax-exempt bonds	(81,000,000)
Available capacity	343,000,000
Revolving Credit Facility | Piedmont
Line of Credit Facility [Line Items]
Facility Size	600,000,000
Commercial Paper	(414,000,000)
Outstanding letters of credit	(2,000,000)
Available capacity	184,000,000
Proceeds Loaned To Subsidiary Registrants | Revolving Credit Facility | Parent Company
Line of Credit Facility [Line Items]
Commercial Paper	$ (625,000,000)

Debt and Credit Facilities (Nar

Debt and Credit Facilities (Narrative) (Details)	1 Months Ended		12 Months Ended
	Jun. 30, 2020USD ($)	May 31, 2019USD ($)	Dec. 31, 2019USD ($)	Jan. 31, 2020USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Debt issuances			$ 6,210,000,000		$ 5,050,000,000
Demand notes, maximum amount available for sale			3,000,000,000
Demand notes, maximum amount outstanding			1,500,000,000
Principal amount of demand notes			1,049,000,000		1,010,000,000
Other loans outstanding against cash surrender value of life insurance policies			$ 777,000,000		741,000,000
Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
June 2017 Three Year Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 1,000,000,000
Term of debt instrument			3 years
Long-term line of credit			$ 500,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			8,000,000,000
Duke Energy Carolinas
Debt Instrument [Line Items]
Debt issuances			$ 800,000,000		2,000,000,000
Duke Energy Carolinas | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Carolinas | Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 1,500,000,000
Progress Energy | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Progress
Debt Instrument [Line Items]
Debt issuances			$ 600,000,000		800,000,000
Other loans outstanding against cash surrender value of life insurance policies			$ 36,000,000		37,000,000
Duke Energy Progress | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Progress | Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 1,250,000,000
Duke Energy Progress | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Facility Size					700,000,000
Term of debt instrument			2 years
Long-term line of credit			$ 700,000,000
Piedmont
Debt Instrument [Line Items]
Debt issuances			$ 600,000,000
Proceeds from issuance of debt		$ 600,000,000
Piedmont | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.70
Piedmont | Term Loan
Debt Instrument [Line Items]
Repayments of debt		$ 350,000,000
Piedmont | Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 600,000,000
Duke Energy Florida
Debt Instrument [Line Items]
Debt issuances			$ 900,000,000		$ 1,000,000,000
Duke Energy Florida | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Florida | Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 800,000,000
Duke Energy Ohio
Debt Instrument [Line Items]
Debt issuances			$ 1,010,000,000
Duke Energy Ohio | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Ohio | Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 600,000,000
Duke Energy Indiana
Debt Instrument [Line Items]
Debt issuances			$ 500,000,000
Duke Energy Indiana | Maximum
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Indiana | Revolving Credit Facility
Debt Instrument [Line Items]
Facility Size			$ 600,000,000
North Carolina Ash Basins | USDOJ | Duke Energy Carolinas | Revolving Credit Facility
Debt Instrument [Line Items]
Minimum master credit facility balance required			250,000,000
North Carolina Ash Basins | USDOJ | Duke Energy Progress | Revolving Credit Facility
Debt Instrument [Line Items]
Minimum master credit facility balance required			$ 250,000,000
Subsequent Event | January 2019 Debt Issuance Due August 2049 | First Mortgage
Debt Instrument [Line Items]
Debt issuances				$ 900,000,000
Subsequent Event | January 2020 Debt Issuance 2.45% Due August 2049 | First Mortgage
Debt Instrument [Line Items]
Debt issuances				$ 500,000,000
Interest rate				2.45%
Subsequent Event | January 2020 Debt Issuance 3.20% Due August 2049 | First Mortgage
Debt Instrument [Line Items]
Debt issuances				$ 400,000,000
Interest rate				3.20%
Forecast | Bonds Maturing June 2020, 4.300% Coupon
Debt Instrument [Line Items]
Interest rate	4.30%
Repayments of debt	$ 450,000,000

Guarantees and Indemnificatio_2

Guarantees and Indemnifications (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Oct. 31, 2017
Guarantor Obligations [Line Items]
Unused letters of credit	$ 81
Face value of guarantees	23	$ 23
Letters of credit
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	634
ACP
Guarantor Obligations [Line Items]
Maximum borrowing capacity			$ 3,400
Performance guarantee
Guarantor Obligations [Line Items]
Maximum potential of future amounts associated with guarantees with expiration dates	114
Performance guarantee | Customers and other third parties
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	128
Performance guarantee | Spectra Capital
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	65
Financial guarantee | ACP
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	$ 827
Maximum exposure percentage	47.00%

Joint Ownership of Generating_3

Joint Ownership of Generating and Transmission Facilities (Schedule Joint Ownership of Generating and Transmission Facilities) (Details) $ in Millions	Dec. 31, 2019USD ($)
Duke Energy Carolinas | Catawba (units 1 and 2)
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	19.25%
Property, plant, and equipment	$ 1,011
Accumulated depreciation	510
Construction work in progress	$ 21
Duke Energy Carolinas | W.S. Lee CC
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	87.27%
Property, plant, and equipment	$ 609
Accumulated depreciation	32
Construction work in progress	$ 1
Duke Energy Indiana | Gibson (unit 5)
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	50.05%
Property, plant, and equipment	$ 410
Accumulated depreciation	183
Construction work in progress	$ 3
Duke Energy Indiana | Vermillion
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	62.50%
Property, plant, and equipment	$ 172
Accumulated depreciation	119
Duke Energy Indiana | Transmission and local facilities
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	5,421
Accumulated depreciation	1,436
Construction work in progress	$ 172

Asset Retirement Obligations (R

Asset Retirement Obligations (Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	$ 13,318	$ 10,467	$ 10,175
Less: current portion	881	919
Total noncurrent asset retirement obligation	12,437	9,548
Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,633
Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,333
Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	352
Duke Energy Carolinas
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	5,734	3,949	3,610
Less: current portion	206	290
Total noncurrent asset retirement obligation	5,528	3,659
Duke Energy Carolinas | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,551
Duke Energy Carolinas | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	3,118
Duke Energy Carolinas | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	65
Progress Energy
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,471	5,411	5,414
Less: current portion	485	514
Total noncurrent asset retirement obligation	5,986	4,897
Progress Energy | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	4,028
Progress Energy | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,368
Progress Energy | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	75
Duke Energy Progress
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	5,893	4,820	4,673
Less: current portion	485	509
Total noncurrent asset retirement obligation	5,408	4,311
Duke Energy Progress | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	3,499
Duke Energy Progress | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,352
Duke Energy Progress | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	42
Duke Energy Florida
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	578	591	742
Less: current portion		5
Total noncurrent asset retirement obligation	578	586
Duke Energy Florida | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	529
Duke Energy Florida | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	16
Duke Energy Florida | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	33
Duke Energy Ohio
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	80	93	84
Less: current portion	1	6
Total noncurrent asset retirement obligation	79	87
Duke Energy Ohio | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	41
Duke Energy Ohio | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	39
Duke Energy Indiana
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	832	722	781
Less: current portion	189	109
Total noncurrent asset retirement obligation	643	613
Duke Energy Indiana | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	805
Duke Energy Indiana | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	27
Piedmont
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	17	19	$ 15
Total noncurrent asset retirement obligation	17	$ 19
Piedmont | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	$ 17

Asset Retirement Obligations (N

Asset Retirement Obligations (NDTF Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
NDTF Information [Abstract]
Annual funding requirement	$ 24
Decommissioning costs	9,152
Legally restricted NDTF investments, fair value	6,766	$ 5,579
Duke Energy Carolinas
NDTF Information [Abstract]
Decommissioning costs	4,365
Legally restricted NDTF investments, fair value	3,837	3,133
Duke Energy Progress
NDTF Information [Abstract]
Annual funding requirement	24
Decommissioning costs	4,181
Legally restricted NDTF investments, fair value	2,929	$ 2,446
Duke Energy Florida
NDTF Information [Abstract]
Decommissioning costs	$ 606

Asset Retirement Obligations _2

Asset Retirement Obligations (Rollforward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation [Line Items]
Beginning Balance	$ 10,467	$ 10,175
Accretion expense	508	427
Liabilities settled	(895)	(638)
Liabilities incurred in the current year	25	39
Revisions in estimates of cash flows	3,213	464
Ending Balance	13,318	10,467
Duke Energy Carolinas
Asset Retirement Obligation [Line Items]
Beginning Balance	3,949	3,610
Accretion expense	235	179
Liabilities settled	(329)	(281)
Liabilities incurred in the current year	18	8
Revisions in estimates of cash flows	1,861	433
Ending Balance	5,734	3,949
Progress Energy
Asset Retirement Obligation [Line Items]
Beginning Balance	5,411	5,414
Accretion expense	252	225
Liabilities settled	(499)	(272)
Liabilities incurred in the current year	7	5
Revisions in estimates of cash flows	1,300	39
Ending Balance	6,471	5,411
Duke Energy Progress
Asset Retirement Obligation [Line Items]
Beginning Balance	4,820	4,673
Accretion expense	227	196
Liabilities settled	(460)	(227)
Revisions in estimates of cash flows	1,306	178
Ending Balance	5,893	4,820
Duke Energy Florida
Asset Retirement Obligation [Line Items]
Beginning Balance	591	742
Accretion expense	25	29
Liabilities settled	(39)	(45)
Liabilities incurred in the current year	7	5
Revisions in estimates of cash flows	(6)	(140)
Ending Balance	578	591
Duke Energy Ohio
Asset Retirement Obligation [Line Items]
Beginning Balance	93	84
Accretion expense	3	4
Liabilities settled	(12)	(5)
Revisions in estimates of cash flows	(4)	10
Ending Balance	80	93
Duke Energy Indiana
Asset Retirement Obligation [Line Items]
Beginning Balance	722	781
Accretion expense	28	29
Liabilities settled	(54)	(79)
Liabilities incurred in the current year		25
Revisions in estimates of cash flows	136	(34)
Ending Balance	832	722
Piedmont
Asset Retirement Obligation [Line Items]
Beginning Balance	19	15
Accretion expense	1	1
Revisions in estimates of cash flows	(3)	3
Ending Balance	$ 17	$ 19

Property, Plant and Equipment_2

Property, Plant and Equipment (Schedule Of Property, Plant and Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	$ 2,091	$ 2,072
Other buildings and improvements	4,916	4,675
Equipment	2,313	2,141
Construction in process	6,102	5,726
Total property, plant and equipment	147,654	134,458
Generation facilities to be retired, net	246	362
Total net property, plant and equipment	102,127	91,694
Finance lease asset	952
Finance lease accumulated amortization	(6)
Capitalized leases		1,237
Accumulated amortization on capitalized leases		61
Capitalized Interest Costs [Abstract]
Capitalized interest	$ 159	$ 161	$ 128
Minimum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	2 years	3 years
Equipment, estimated useful life, years	3 years	3 years
Maximum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	40 years	40 years
Equipment, estimated useful life, years	25 years	55 years
Nuclear fuel
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Nuclear fuel	$ 3,253	$ 3,460
Accumulated depreciation and amortization	(1,807)	(1,947)
VIE
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total property, plant and equipment	5,747	4,007
Accumulated depreciation and amortization	(1,041)	(698)
Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(43,419)	(41,079)
Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	$ 111,739	$ 100,706
Regulated | Electric generation, distribution and transmission | Minimum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	15 years	15 years
Regulated | Electric generation, distribution and transmission | Maximum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	100 years	100 years
Regulated | Natural gas transmission and distribution
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	$ 9,839	$ 8,808
Regulated | Natural gas transmission and distribution | Minimum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	4 years	12 years
Regulated | Natural gas transmission and distribution | Maximum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	73 years	80 years
Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	$ 1,810	$ 1,966
Regulated | Other buildings and improvements | Minimum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	23 years	24 years
Regulated | Other buildings and improvements | Maximum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	90 years	90 years
Nonregulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	$ (2,354)	$ (2,047)
Finance lease accumulated amortization	(20)
Nonregulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	$ 5,103	$ 4,410
Nonregulated | Electric generation, distribution and transmission | Minimum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	5 years	5 years
Nonregulated | Electric generation, distribution and transmission | Maximum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	30 years	30 years
Nonregulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	$ 488	$ 494
Nonregulated | Other buildings and improvements | Minimum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	25 years	25 years
Nonregulated | Other buildings and improvements | Maximum
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	35 years	35 years
Duke Energy Carolinas
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	$ 520	$ 472
Other buildings and improvements	1,139	1,077
Equipment	546	467
Construction in process	1,389	1,678
Total property, plant and equipment	48,922	44,741
Total net property, plant and equipment	32,397	29,245
Finance lease asset	211
Finance lease accumulated amortization	(13)
Capitalized leases		135
Accumulated amortization on capitalized leases		12
Capitalized Interest Costs [Abstract]
Capitalized interest	30	35	45
Duke Energy Carolinas | Nuclear fuel
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Nuclear fuel	1,891	1,898
Accumulated depreciation and amortization	(1,082)	(1,087)
Duke Energy Carolinas | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(16,525)	(15,496)
Duke Energy Carolinas | Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	42,723	38,468
Duke Energy Carolinas | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	714	681
Progress Energy
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	884	868
Other buildings and improvements	1,467	1,354
Equipment	665	565
Construction in process	2,149	2,515
Total property, plant and equipment	55,070	50,260
Generation facilities to be retired, net	246	362
Total net property, plant and equipment	38,157	34,224
Finance lease asset	443
Finance lease accumulated amortization	(143)
Capitalized leases		257
Accumulated amortization on capitalized leases		131
Capitalized Interest Costs [Abstract]
Capitalized interest	31	51	45
Progress Energy | Nuclear fuel
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Nuclear fuel	1,362	1,562
Accumulated depreciation and amortization	(725)	(860)
Progress Energy | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(17,159)	(16,398)
Progress Energy | Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	48,142	42,760
Progress Energy | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	401	636
Duke Energy Progress
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	449	445
Other buildings and improvements	1,046	952
Equipment	452	399
Construction in process	1,114	1,659
Total property, plant and equipment	34,603	31,459
Generation facilities to be retired, net	246	362
Total net property, plant and equipment	22,934	20,398
Finance lease asset	308
Finance lease accumulated amortization	(17)
Capitalized leases		137
Accumulated amortization on capitalized leases		14
Capitalized Interest Costs [Abstract]
Capitalized interest	28	26	21
Duke Energy Progress | Nuclear fuel
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Nuclear fuel	1,362	1,562
Accumulated depreciation and amortization	(725)	(860)
Duke Energy Progress | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(11,915)	(11,423)
Duke Energy Progress | Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	30,018	26,147
Duke Energy Progress | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	162	295
Duke Energy Florida
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	435	423
Other buildings and improvements	411	393
Equipment	213	166
Construction in process	1,035	856
Total property, plant and equipment	20,457	18,792
Total net property, plant and equipment	15,221	13,824
Finance lease asset	135
Finance lease accumulated amortization	(126)
Capitalized leases		120
Accumulated amortization on capitalized leases		117
Capitalized Interest Costs [Abstract]
Capitalized interest	3	25	24
Duke Energy Florida | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(5,236)	(4,968)
Duke Energy Florida | Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	18,124	16,613
Duke Energy Florida | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	239	341
Duke Energy Ohio
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	150	136
Other buildings and improvements	269	257
Equipment	319	384
Construction in process	504	412
Total property, plant and equipment	10,241	9,360
Total net property, plant and equipment	7,398	6,643
Capitalized leases		73
Accumulated amortization on capitalized leases		20
Capitalized Interest Costs [Abstract]
Capitalized interest	22	17	10
Duke Energy Ohio | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(2,843)	(2,717)
Duke Energy Ohio | Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	5,838	5,182
Duke Energy Ohio | Regulated | Natural gas transmission and distribution
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	2,892	2,719
Duke Energy Ohio | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	269	270
Duke Energy Indiana
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	117	116
Other buildings and improvements	292	279
Equipment	205	178
Construction in process	381	325
Total property, plant and equipment	16,305	15,443
Total net property, plant and equipment	11,072	10,529
Finance lease asset	10
Finance lease accumulated amortization	(3)
Capitalized leases		35
Accumulated amortization on capitalized leases		10
Capitalized Interest Costs [Abstract]
Capitalized interest	26	27	9
Duke Energy Indiana | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(5,233)	(4,914)
Duke Energy Indiana | Regulated | Electric generation, distribution and transmission
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	15,032	14,292
Duke Energy Indiana | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	278	253
Piedmont
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	388	448
Other buildings and improvements	304	300
Equipment	128	141
Construction in process	531	382
Total property, plant and equipment	8,446	7,486
Total net property, plant and equipment	6,765	5,911
Capitalized Interest Costs [Abstract]
Capitalized interest	26	17	$ 12
Piedmont | Regulated
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Accumulated depreciation and amortization	(1,681)	(1,575)
Piedmont | Regulated | Natural gas transmission and distribution
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	6,947	6,089
Piedmont | Regulated | Other buildings and improvements
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other buildings and improvements	$ 148	$ 126

Property, Plant and Equipment_3

Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Net property, plant and equipment	$ 102,127	$ 91,694
Impairment charges	(8)	$ 402	$ 282
Wind project
Property, Plant and Equipment [Line Items]
Impairment charges			69
Renewable merchant plants
Property, Plant and Equipment [Line Items]
Net property, plant and equipment	$ 160
Property, plant and equipment
Property, Plant and Equipment [Line Items]
Impairment charges			58
Net intangible assets
Property, Plant and Equipment [Line Items]
Impairment charges			$ 11

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Goodwill By Reportable Operating Segment) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill, balance			$ 19,425,000,000	$ 19,425,000,000
Goodwill [Roll Forward]
Accumulated impairment charges			(122,000,000)	(122,000,000)
Goodwill, Ending balance	$ 19,303,000,000
Goodwill	19,303,000,000		19,303,000,000	19,303,000,000
Commercial Renewables
Goodwill [Line Items]
Goodwill, balance			122,000,000	122,000,000
Goodwill [Roll Forward]
Accumulated impairment charges			(122,000,000)	(122,000,000)
Impairment charges	93,000,000	$ 29,000,000
Electric Utilities and Infrastructure
Goodwill [Line Items]
Goodwill, balance			17,379,000,000	17,379,000,000
Goodwill [Roll Forward]
Goodwill, Ending balance	17,379,000,000
Goodwill	17,379,000,000		17,379,000,000	17,379,000,000
Gas Utilities and Infrastructure
Goodwill [Line Items]
Goodwill, balance			1,924,000,000	1,924,000,000
Goodwill [Roll Forward]
Goodwill, Ending balance	1,924,000,000
Goodwill	1,924,000,000		1,924,000,000	1,924,000,000
Duke Energy Ohio
Goodwill [Roll Forward]
Accumulated impairment charges			(216,000,000)	(216,000,000)
Goodwill, Ending balance	920,000,000
Goodwill	920,000,000		920,000,000	920,000,000
Duke Energy Ohio | Electric Utilities and Infrastructure
Goodwill [Roll Forward]
Goodwill, Ending balance	596,000,000
Goodwill	596,000,000		596,000,000	596,000,000
Duke Energy Ohio | Gas Utilities and Infrastructure
Goodwill [Roll Forward]
Goodwill, Ending balance	324,000,000
Goodwill	324,000,000		324,000,000	324,000,000
Progress Energy
Goodwill [Roll Forward]
Accumulated impairment charges			0
Goodwill, Ending balance	3,655,000,000
Goodwill	3,655,000,000		3,655,000,000	3,655,000,000
Piedmont
Goodwill [Roll Forward]
Accumulated impairment charges			0
Goodwill, Ending balance	49,000,000
Goodwill	$ 49,000,000		$ 49,000,000	$ 49,000,000

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	$ 305	$ 300
Accumulated amortization	(56)	(54)
Total intangible assets, net	249	246
Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	18	18
Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	172	168
Natural gas, coal and power contracts
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	(21)	(20)
Renewable operating and development projects
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	89	84
Accumulated amortization	(34)	(29)
Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	6
Accumulated amortization	(1)	(5)
Duke Energy Carolinas
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	53	46
Total intangible assets, net	53	46
Duke Energy Carolinas | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0	0
Duke Energy Carolinas | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	53	46
Progress Energy
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	123	125
Total intangible assets, net	123	125
Progress Energy | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	5	5
Progress Energy | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	118	120
Duke Energy Progress
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	120	122
Total intangible assets, net	120	122
Duke Energy Progress | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	2
Duke Energy Progress | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	118	120
Duke Energy Florida
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Total intangible assets, net	3	3
Duke Energy Florida | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Duke Energy Ohio
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	1	2
Total intangible assets, net	1	2
Duke Energy Ohio | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0	0
Duke Energy Ohio | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	1	2
Duke Energy Ohio | Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0	0
Accumulated amortization	0	0
Duke Energy Indiana
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	36	36
Accumulated amortization	(21)	(20)
Total intangible assets, net	15	16
Duke Energy Indiana | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	12	12
Duke Energy Indiana | Natural gas, coal and power contracts
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	$ (21)	(20)
Piedmont
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount		3
Accumulated amortization		(3)
Piedmont | Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount		3
Accumulated amortization		$ (3)

Investments in Unconsolidated_3

Investments in Unconsolidated Affiliates (Investments in Equity Method Unconsolidated Affiliates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,936	$ 1,409	$ 1,175
Equity in earnings of unconsolidated affiliates	162	83	119
Electric Utilities and Infrastructure
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	122	97	89
Equity in earnings of unconsolidated affiliates	9	6	5
Gas Utilities and Infrastructure
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	1,388	1,003	763
Equity in earnings of unconsolidated affiliates	114	27	62
Commercial Renewables
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	314	201	190
Equity in earnings of unconsolidated affiliates	(4)	(1)	(5)
Other
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	112	108	133
Equity in earnings of unconsolidated affiliates	$ 43	$ 51	$ 57

Investments in Unconsolidated_4

Investments in Unconsolidated Affiliates (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 06, 2019	Sep. 05, 2019	Dec. 31, 2016
Investments In Unconsolidated Affiliates [Line Items]
Distributions from equity investments	$ 55	$ 108	$ 13
Distributions from equity investments, return of capital	$ 11	137	$ 281
Constitution | VIE, Not Primary Beneficiary
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	24.00%
ACP
Investments In Unconsolidated Affiliates [Line Items]
Distributions from equity investments, return of capital	$ 265
Electric Utilities and Infrastructure | DATC
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	50.00%
Electric Utilities and Infrastructure | Pioneer
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	50.00%
Commercial Renewables | DS Cornerstone
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest				26.00%	50.00%
Gas Utilities and Infrastructure | Constitution | VIE, Not Primary Beneficiary
Investments In Unconsolidated Affiliates [Line Items]
OTTI impairment loss	$ 25	55
Gas Utilities and Infrastructure | ACP
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	47.00%
Gas Utilities and Infrastructure | Constitution
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	24.00%
Gas Utilities and Infrastructure | Constitution | Constitution | VIE, Not Primary Beneficiary
Investments In Unconsolidated Affiliates [Line Items]
OTTI impairment loss	$ 25
Other | NMC
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	17.50%		17.50%			25.00%
Board representation and voting rights, ownership percentage	25.00%
Piedmont
Investments In Unconsolidated Affiliates [Line Items]
Distributions from equity investments	$ 1	1	$ 4
Distributions from equity investments, return of capital	$ 4	$ 3	$ 2

Investments in Unconsolidated_5

Investments in Unconsolidated Affiliates (Gas Utilities and Infrastructure Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,936	$ 1,409	$ 1,175
Return of investment capital	11	137	281
ACP
Investments In Unconsolidated Affiliates [Line Items]
Return of investment capital	265
Gas Utilities and Infrastructure
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,388	1,003	763
Gas Utilities and Infrastructure | ACP
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	47.00%
Investments in equity method unconsolidated affiliates	$ 1,179	797
Gas Utilities and Infrastructure | Sabal Trail
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	7.50%
Investments in equity method unconsolidated affiliates	$ 121	112
Return of investment capital		112
Gas Utilities and Infrastructure | Constitution
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	24.00%
Investments in equity method unconsolidated affiliates		25
Piedmont
Investments In Unconsolidated Affiliates [Line Items]
Investments in equity method unconsolidated affiliates	$ 83	64
Return of investment capital	$ 4	3	$ 2
Piedmont | Gas Utilities and Infrastructure | Cardinal
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	21.49%
Investments in equity method unconsolidated affiliates	$ 9	10
Piedmont | Gas Utilities and Infrastructure | Pine Needle
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	45.00%
Investments in equity method unconsolidated affiliates	$ 28	13
Piedmont | Gas Utilities and Infrastructure | Hardy Storage
Investments In Unconsolidated Affiliates [Line Items]
Ownership interest	50.00%
Investments in equity method unconsolidated affiliates	$ 51	$ 46

Related Party Transactions (Oth

Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Duke Energy Carolinas | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 841	$ 985	$ 858
Duke Energy Carolinas | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	20	22	23
Duke Energy Carolinas | Joint Dispatch Agreement (JDA) revenue | Duke Energy Progress
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	186	207	145
Related party transaction, other revenues from transactions with related party	60	84	49
Duke Energy Carolinas | Intercompany natural gas transactions | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	15	15	9
Progress Energy | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	778	906	736
Progress Energy | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	37	34	38
Progress Energy | Joint Dispatch Agreement (JDA) revenue | Duke Energy Carolinas
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	60	84	49
Related party transaction, other revenues from transactions with related party	186	207	145
Progress Energy | Intercompany natural gas transactions | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	76	78	77
Duke Energy Progress | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	462	577	438
Duke Energy Progress | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	15	13	15
Duke Energy Progress | Joint Dispatch Agreement (JDA) revenue | Duke Energy Carolinas
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	60	84	49
Related party transaction, other revenues from transactions with related party	186	207	145
Duke Energy Progress | Intercompany natural gas transactions | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	76	78	77
Duke Energy Florida | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	316	329	298
Duke Energy Florida | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	22	21	23
Duke Energy Ohio | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	354	374	363
Duke Energy Ohio | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	5	5
Duke Energy Indiana | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	412	405	370
Duke Energy Indiana | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	7	7	8
Piedmont | Corporate governance and shared service expenses | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	138	170	50
Piedmont | Indemnification coverages | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	3	2	2
Piedmont | Intercompany natural gas transactions | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	91	93	86
Piedmont | Natural gas storage and transportation costs | Affiliated entity
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 23	$ 25	$ 25

Related Party Transactions (Int

Related Party Transactions (Intercompany Income Taxes) (Details) - Affiliated entity - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Duke Energy Carolinas
Related Party Transaction [Line Items]
Intercompany income tax receivable		$ 52
Intercompany income tax payable	$ 5
Progress Energy
Related Party Transaction [Line Items]
Intercompany income tax receivable	125	47
Duke Energy Progress
Related Party Transaction [Line Items]
Intercompany income tax receivable	28	29
Duke Energy Florida
Related Party Transaction [Line Items]
Intercompany income tax payable	2	16
Duke Energy Ohio
Related Party Transaction [Line Items]
Intercompany income tax receivable	9
Intercompany income tax payable		3
Duke Energy Indiana
Related Party Transaction [Line Items]
Intercompany income tax receivable	28	8
Piedmont
Related Party Transaction [Line Items]
Intercompany income tax receivable	$ 13
Intercompany income tax payable		$ 45

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)GWhsharesMcf	Dec. 31, 2018USD ($)GWhMcf
Call options
Derivative [Line Items]
Aggregate notional amount | shares	305,000
Put options
Derivative [Line Items]
Aggregate notional amount | shares	305,000
Interest Rate Contracts
Derivative [Line Items]
Notional Amount	$ 2,270	$ 2,644
Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	993	923
Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount	$ 1,277	$ 1,721
Commodity contracts | Electricity (GWh)
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	15,858	15,286
Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	704	739
VIE | Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	$ 693	$ 422
VIE | Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount		194
Duke Energy Carolinas | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	450	300
Duke Energy Carolinas | Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	0	0
Duke Energy Carolinas | Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount	$ 450	$ 300
Duke Energy Carolinas | Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	130	121
Progress Energy | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	$ 800	$ 1,200
Progress Energy | Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	0	0
Progress Energy | Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount	$ 800	$ 1,200
Progress Energy | Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	160	169
Duke Energy Progress | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	$ 250	$ 650
Duke Energy Progress | Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	0	0
Duke Energy Progress | Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount	$ 250	$ 650
Duke Energy Progress | Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	160	166
Duke Energy Florida | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	$ 550	$ 550
Duke Energy Florida | Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	0	0
Duke Energy Florida | Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount	550	$ 550
Duke Energy Florida | Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf		3
Duke Energy Ohio | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	27	$ 27
Duke Energy Ohio | Interest Rate Contracts | Designated contracts
Derivative [Line Items]
Notional Amount	0	0
Duke Energy Ohio | Interest Rate Contracts | Undesignated contracts
Derivative [Line Items]
Notional Amount	$ 27	$ 27
Duke Energy Ohio | Commodity contracts | Electricity (GWh)
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	1,887	1,786
Duke Energy Indiana | Commodity contracts | Electricity (GWh)
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	13,971	13,500
Duke Energy Indiana | Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	3	1
Piedmont | Commodity contracts | Natural gas (millions of Dth)
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	411	448

Derivatives and Hedging (Locati

Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 25	$ 57
Location and fair value amounts of derivatives (Liability)	300	242
Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	24	38
Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	19
Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	118	68
Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	182	174
Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	18	39
Location and fair value amounts of derivatives (Liability)	223	191
Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	18
Location and fair value amounts of derivatives (Liability)	53	51
Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	24
Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	12
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	21	6
Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	35
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	4
Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	67	33
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	156	158
Not Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	2
Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	23
Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	10
Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		12
Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Carolinas
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	49	33
Duke Energy Carolinas | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Carolinas | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Carolinas | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	39	23
Duke Energy Carolinas | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10	10
Duke Energy Carolinas | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	43	24
Duke Energy Carolinas | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	9
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	33	14
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10	10
Duke Energy Carolinas | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	9
Progress Energy
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	4
Location and fair value amounts of derivatives (Liability)	88	44
Progress Energy | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	2
Progress Energy | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	51	23
Progress Energy | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	21
Progress Energy | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	63	25
Progress Energy | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Location and fair value amounts of derivatives (Liability)	1	19
Progress Energy | Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	24
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	10
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	15
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	13
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Progress Energy | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Progress Energy | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Progress
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	49	27
Duke Energy Progress | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	27	16
Duke Energy Progress | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	11
Duke Energy Progress | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	48	11
Duke Energy Progress | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	16
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	5
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	6
Duke Energy Progress | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	11
Duke Energy Progress | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Florida
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Location and fair value amounts of derivatives (Liability)	24	9
Duke Energy Florida | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Duke Energy Florida | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24	8
Duke Energy Florida | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Florida | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Duke Energy Florida | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Location and fair value amounts of derivatives (Liability)		3
Duke Energy Florida | Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Florida | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Duke Energy Florida | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Duke Energy Florida | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Florida | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Florida | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Florida | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Ohio
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	6
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Ohio | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Duke Energy Ohio | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Ohio | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	4
Duke Energy Ohio | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	6
Duke Energy Ohio | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Ohio | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Duke Energy Ohio | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Ohio | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	4
Duke Energy Indiana
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	23
Location and fair value amounts of derivatives (Liability)	1
Duke Energy Indiana | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	23
Duke Energy Indiana | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1
Duke Energy Indiana | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	23
Location and fair value amounts of derivatives (Liability)	1
Duke Energy Indiana | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	23
Duke Energy Indiana | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1
Piedmont
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Location and fair value amounts of derivatives (Liability)	117	141
Piedmont | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Piedmont | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	8
Piedmont | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	110	133
Piedmont | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Location and fair value amounts of derivatives (Liability)	117	141
Piedmont | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		0
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		0
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	8
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 110	$ 133

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Gross amounts recognized	$ 25	$ 57
Net amounts presented on Balance Sheets	25	57
Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	24	38
Gross amounts offset	(1)	(3)
Net amounts presented on Balance Sheets	23	35
Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	1	19
Gross amounts offset		(3)
Net amounts presented on Balance Sheets	1	16
Duke Energy Carolinas
Offsetting Assets [Line Items]
Gross amounts recognized		3
Net amounts presented on Balance Sheets		3
Duke Energy Carolinas | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Carolinas | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		1
Gross amounts offset		(1)
Progress Energy
Offsetting Assets [Line Items]
Gross amounts recognized	7	4
Net amounts presented on Balance Sheets	7	4
Progress Energy | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	7	2
Gross amounts offset	(1)	(2)
Net amounts presented on Balance Sheets	6
Progress Energy | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Progress
Offsetting Assets [Line Items]
Gross amounts recognized		4
Net amounts presented on Balance Sheets		4
Duke Energy Progress | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Progress | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Florida
Offsetting Assets [Line Items]
Gross amounts recognized	7
Net amounts presented on Balance Sheets	7
Duke Energy Florida | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	7
Gross amounts offset	(1)
Net amounts presented on Balance Sheets	6
Duke Energy Ohio
Offsetting Assets [Line Items]
Gross amounts recognized	4	6
Duke Energy Ohio | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	3	6
Net amounts presented on Balance Sheets	3	6
Duke Energy Ohio | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	1
Net amounts presented on Balance Sheets	1
Duke Energy Indiana
Offsetting Assets [Line Items]
Gross amounts recognized	13	23
Net amounts presented on Balance Sheets	13	23
Duke Energy Indiana | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	13	23
Net amounts presented on Balance Sheets	13	23
Piedmont
Offsetting Assets [Line Items]
Gross amounts recognized	1	3
Net amounts presented on Balance Sheets	1	3
Piedmont | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	1	3
Net amounts presented on Balance Sheets	$ 1	$ 3

Derivatives and Hedging (Sche_2

Derivatives and Hedging (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Gross amounts recognized	$ 300	$ 242
Net amounts presented on Balance Sheets	277	242
Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	118	68
Gross amounts offset	(24)	(4)
Net amounts presented on Balance Sheets	94	64
Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	182	174
Gross amounts offset		(3)
Net amounts presented on Balance Sheets	182	171
Duke Energy Carolinas
Offsetting Liabilities [Line Items]
Gross amounts recognized	49	33
Net amounts presented on Balance Sheets	49	33
Duke Energy Carolinas | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	39	23
Gross amounts offset		(2)
Net amounts presented on Balance Sheets	39	21
Duke Energy Carolinas | Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	10	10
Gross amounts offset		(1)
Net amounts presented on Balance Sheets	10	9
Progress Energy
Offsetting Liabilities [Line Items]
Gross amounts recognized	88	44
Net amounts presented on Balance Sheets	65	44
Progress Energy | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	51	23
Gross amounts offset	(24)	(2)
Net amounts presented on Balance Sheets	27	21
Progress Energy | Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	37	21
Gross amounts offset		(2)
Net amounts presented on Balance Sheets	37	19
Duke Energy Progress
Offsetting Liabilities [Line Items]
Gross amounts recognized	49	27
Net amounts presented on Balance Sheets	49	27
Duke Energy Progress | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	27	16
Gross amounts offset		(2)
Net amounts presented on Balance Sheets	27	14
Duke Energy Progress | Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	22	11
Gross amounts offset		(2)
Net amounts presented on Balance Sheets	22	9
Duke Energy Florida
Offsetting Liabilities [Line Items]
Gross amounts recognized	24	9
Net amounts presented on Balance Sheets	1	9
Duke Energy Florida | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	24	8
Gross amounts offset	(24)
Net amounts presented on Balance Sheets		8
Duke Energy Florida | Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized		1
Net amounts presented on Balance Sheets		1
Duke Energy Ohio
Offsetting Liabilities [Line Items]
Gross amounts recognized	6	5
Duke Energy Ohio | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	1	1
Net amounts presented on Balance Sheets	1	1
Duke Energy Ohio | Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	5	4
Net amounts presented on Balance Sheets	5	4
Duke Energy Indiana
Offsetting Liabilities [Line Items]
Gross amounts recognized	1
Net amounts presented on Balance Sheets	1
Duke Energy Indiana | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	1
Net amounts presented on Balance Sheets	1
Piedmont
Offsetting Liabilities [Line Items]
Gross amounts recognized	117	141
Net amounts presented on Balance Sheets	117	141
Piedmont | Current Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	7	8
Net amounts presented on Balance Sheets	7	8
Piedmont | Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts recognized	110	133
Net amounts presented on Balance Sheets	$ 110	$ 133

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments That Contain Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	$ 79	$ 44
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	79	44
Duke Energy Carolinas
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	35	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	35	19
Progress Energy
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	44	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	44	25
Duke Energy Progress
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	44	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 44	$ 25

Investments in Debt and Equit_3

Investments in Debt and Equity Securities (Estimated Fair Value of Investments in Debt and Equity Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale
Estimated Fair Value	$ 2,626
Total Investments
Unrealized Holding Gains	3,675	$ 2,458
Unrealized Holding Losses	57	131
Estimated Fair Value	8,562	7,075
NDTF
Equity Securities, FV-NI
Gross Unrealized Holding Gains	3,523	2,402
Gross Unrealized Holding Losses	55	95
Estimated Fair Value	5,661	4,475
Debt Securities, Available-for-sale
Estimated Fair Value	2,469	2,231
Total Investments
Unrealized Holding Gains	3,609	2,421
Unrealized Holding Losses	57	126
Estimated Fair Value	8,130	6,706
NDTF | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments	101	88
NDTF | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	37	4
Gross Unrealized Holding Losses	1	13
Estimated Fair Value	603	566
NDTF | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	13	1
Gross Unrealized Holding Losses	0	4
Estimated Fair Value	368	353
NDTF | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	33	14
Gross Unrealized Holding Losses	1	12
Estimated Fair Value	1,256	1,076
NDTF | Other debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	0
Gross Unrealized Holding Losses	0	2
Estimated Fair Value	141	148
Other Investments
Equity Securities, FV-NI
Gross Unrealized Holding Gains	57	36
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	122	99
Debt Securities, Available-for-sale
Estimated Fair Value	310	270
Total Investments
Unrealized Holding Gains	66	37
Unrealized Holding Losses	0	5
Estimated Fair Value	432	369
Other Investments | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments	52	22
Other Investments | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	0
Gross Unrealized Holding Losses	0	2
Estimated Fair Value	67	60
Other Investments | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	94	85
Other Investments | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	41	45
Other Investments | Other debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	56	58
Duke Energy Carolinas
Equity Securities, FV-NI
Estimated Fair Value		2,484
Debt Securities, Available-for-sale
Estimated Fair Value	1,172
Duke Energy Carolinas | NDTF
Equity Securities, FV-NI
Gross Unrealized Holding Gains	1,914	1,309
Gross Unrealized Holding Losses	8	54
Estimated Fair Value	3,154	2,484
Debt Securities, Available-for-sale
Estimated Fair Value	1,193	1,069
Total Investments
Unrealized Holding Gains	1,957	1,316
Unrealized Holding Losses	10	74
Estimated Fair Value	4,347	3,553
Duke Energy Carolinas | NDTF | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments	21	29
Duke Energy Carolinas | NDTF | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	21	2
Gross Unrealized Holding Losses	1	9
Estimated Fair Value	361	341
Duke Energy Carolinas | NDTF | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	96	81
Duke Energy Carolinas | NDTF | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	16	5
Gross Unrealized Holding Losses	1	8
Estimated Fair Value	578	475
Duke Energy Carolinas | NDTF | Other debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	0
Gross Unrealized Holding Losses	0	2
Estimated Fair Value	137	143
Progress Energy
Debt Securities, Available-for-sale
Estimated Fair Value	1,247
Total Investments
Unrealized Holding Gains	1,655	1,105
Unrealized Holding Losses	47	52
Estimated Fair Value	3,883	3,217
Progress Energy | NDTF
Equity Securities, FV-NI
Gross Unrealized Holding Gains	1,609	1,093
Gross Unrealized Holding Losses	47	41
Estimated Fair Value	2,507	1,991
Debt Securities, Available-for-sale
Estimated Fair Value	1,276	1,162
Total Investments
Unrealized Holding Gains	1,652	1,105
Unrealized Holding Losses	47	52
Estimated Fair Value	3,783	3,153
Progress Energy | NDTF | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments	80	59
Progress Energy | NDTF | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	16	2
Gross Unrealized Holding Losses	0	4
Estimated Fair Value	242	225
Progress Energy | NDTF | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	10	1
Gross Unrealized Holding Losses	0	3
Estimated Fair Value	272	272
Progress Energy | NDTF | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	17	9
Gross Unrealized Holding Losses	0	4
Estimated Fair Value	678	601
Progress Energy | NDTF | Other debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	4	5
Progress Energy | Other Investments
Debt Securities, Available-for-sale
Estimated Fair Value	100	64
Total Investments
Unrealized Holding Gains	3	0
Unrealized Holding Losses	0	0
Estimated Fair Value	100	64
Progress Energy | Other Investments | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments	49	17
Progress Energy | Other Investments | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	51	47
Duke Energy Progress
Debt Securities, Available-for-sale
Estimated Fair Value	921
Total Investments
Unrealized Holding Gains	1,300	842
Unrealized Holding Losses	21	39
Estimated Fair Value	3,053	2,500
Duke Energy Progress | NDTF
Available-for-sale Securities
Cash And Cash Equivalent Investments	53
Equity Securities, FV-NI
Gross Unrealized Holding Gains	1,258	833
Gross Unrealized Holding Losses	21	30
Estimated Fair Value	2,077	1,588
Debt Securities, Available-for-sale
Estimated Fair Value	974	906
Total Investments
Unrealized Holding Gains	1,300	842
Unrealized Holding Losses	21	39
Estimated Fair Value	3,051	2,494
Duke Energy Progress | NDTF | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments		46
Duke Energy Progress | NDTF | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	16	2
Gross Unrealized Holding Losses	0	3
Estimated Fair Value	242	171
Duke Energy Progress | NDTF | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	10	1
Gross Unrealized Holding Losses	0	3
Estimated Fair Value	272	271
Duke Energy Progress | NDTF | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	16	6
Gross Unrealized Holding Losses	0	3
Estimated Fair Value	403	415
Duke Energy Progress | NDTF | Other debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	4	3
Duke Energy Progress | Other Investments
Available-for-sale Securities
Cash And Cash Equivalent Investments	2
Debt Securities, Available-for-sale
Estimated Fair Value	2	6
Total Investments
Unrealized Holding Gains	0	0
Unrealized Holding Losses	0	0
Estimated Fair Value	2	6
Duke Energy Progress | Other Investments | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments		6
Duke Energy Florida
Debt Securities, Available-for-sale
Estimated Fair Value	326
Total Investments
Unrealized Holding Gains	355	263
Unrealized Holding Losses	26	13
Estimated Fair Value	787	707
Duke Energy Florida | NDTF
Available-for-sale Securities
Cash And Cash Equivalent Investments	27
Equity Securities, FV-NI
Gross Unrealized Holding Gains	351	260
Gross Unrealized Holding Losses	26	11
Estimated Fair Value	430	403
Debt Securities, Available-for-sale
Estimated Fair Value	302	256
Total Investments
Unrealized Holding Gains	352	263
Unrealized Holding Losses	26	13
Estimated Fair Value	732	659
Duke Energy Florida | NDTF | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments		13
Duke Energy Florida | NDTF | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	0	54
Duke Energy Florida | NDTF | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0
Estimated Fair Value	0	1
Duke Energy Florida | NDTF | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1	3
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	275	186
Duke Energy Florida | NDTF | Other debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	0	2
Duke Energy Florida | Other Investments
Available-for-sale Securities
Cash And Cash Equivalent Investments	4
Debt Securities, Available-for-sale
Estimated Fair Value	55	48
Total Investments
Unrealized Holding Gains	3	0
Unrealized Holding Losses	0	0
Estimated Fair Value	55	48
Duke Energy Florida | Other Investments | Cash and cash equivalents
Available-for-sale Securities
Cash And Cash Equivalent Investments		1
Duke Energy Florida | Other Investments | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	51	47
Duke Energy Indiana
Equity Securities, FV-NI
Gross Unrealized Holding Gains	43	29
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	81	67
Debt Securities, Available-for-sale
Estimated Fair Value	44
Total Investments
Unrealized Holding Gains	44	29
Unrealized Holding Losses		1
Estimated Fair Value	125	108
Duke Energy Indiana | Corporate debt securities
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	6	8
Duke Energy Indiana | Municipal bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	36	33
Duke Energy Indiana | Other Investments
Equity Securities, FV-NI
Estimated Fair Value	81	67
Debt Securities, Available-for-sale
Estimated Fair Value	44	41
Duke Energy Indiana | Other Investments | U.S. government bonds
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Estimated Fair Value	$ 2	$ 0

Investments in Debt and Equit_4

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Dec. 31, 2019USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 372
Due after one through five years	550
Due after five through 10 years	452
Due after 10 years	1,252
Total	2,626
Duke Energy Carolinas
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	51
Due after one through five years	253
Due after five through 10 years	181
Due after 10 years	687
Total	1,172
Progress Energy
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	311
Due after one through five years	256
Due after five through 10 years	211
Due after 10 years	469
Total	1,247
Duke Energy Progress
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	34
Due after one through five years	247
Due after five through 10 years	204
Due after 10 years	436
Total	921
Duke Energy Florida
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	277
Due after one through five years	9
Due after five through 10 years	7
Due after 10 years	33
Total	326
Duke Energy Indiana
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	4
Due after one through five years	16
Due after five through 10 years	7
Due after 10 years	17
Total	$ 44

Investments in Debt and Equit_5

Investments in Debt and Equity Securities (Realized Gains and Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
FV-NI:
Realized gains	$ 172	$ 168
Realized losses	151	126
AFS:
Realized gains	94	22
Realized losses	67	51
Available-for-sale Securities, Realized Gain (Loss) [Abstract]
Realized gains			$ 202
Realized losses			160
Duke Energy Carolinas
FV-NI:
Realized gains	113	89
Realized losses	107	73
AFS:
Realized gains	55	19
Realized losses	38	35
Available-for-sale Securities, Realized Gain (Loss) [Abstract]
Realized gains			135
Realized losses			103
Progress Energy
FV-NI:
Realized gains	59	79
Realized losses	44	53
AFS:
Realized gains	36	3
Realized losses	29	15
Available-for-sale Securities, Realized Gain (Loss) [Abstract]
Realized gains			65
Realized losses			56
Duke Energy Progress
FV-NI:
Realized gains	38	68
Realized losses	33	48
AFS:
Realized gains	7	2
Realized losses	5	10
Available-for-sale Securities, Realized Gain (Loss) [Abstract]
Realized gains			54
Realized losses			48
Duke Energy Florida
FV-NI:
Realized gains	21	11
Realized losses	11	5
AFS:
Realized gains	29	1
Realized losses	$ 24	$ 5
Available-for-sale Securities, Realized Gain (Loss) [Abstract]
Realized gains			11
Realized losses			$ 8

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 2,626
Derivative assets	25	$ 57
Total assets	8,610	7,132
Derivative liabilities	(277)	(242)
Net assets (liabilities)	8,310	6,890
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	4
Total assets	6,675	5,156
Derivative liabilities	(15)	(11)
Net assets (liabilities)	6,660	5,145
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7	25
Total assets	1,869	1,883
Derivative liabilities	(145)	(90)
Net assets (liabilities)	1,701	1,793
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15	28
Total assets	15	28
Derivative liabilities	(117)	(141)
Net assets (liabilities)	(102)	(113)
Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	51	65
Net assets (liabilities)	51	65
NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	5,684	4,475
NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	5,633	4,410
NDTF equity securities | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	51	65
NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	5,661	4,475
Debt securities, available-for-sale	2,469	2,231
Derivative liabilities	(23)
NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	826	576
NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,643	1,655
Derivative liabilities	(23)
Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	122	99
Debt securities, available-for-sale	310	270
Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	122	99
Debt securities, available-for-sale	91	67
Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	219	203
Duke Energy Carolinas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI		2,484
Debt securities, available-for-sale	1,172
Derivative assets		3
Total assets	4,347	3,556
Derivative liabilities	(49)	(33)
Net assets (liabilities)	4,298	3,523
Duke Energy Carolinas | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI		2,419
Total assets	3,330	2,568
Net assets (liabilities)	3,330	2,568
Duke Energy Carolinas | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		3
Total assets	966	923
Derivative liabilities	(49)	(33)
Net assets (liabilities)	917	890
Duke Energy Carolinas | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI		65
Total assets	51	65
Net assets (liabilities)	51	65
Duke Energy Carolinas | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,154
Duke Energy Carolinas | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,103
Duke Energy Carolinas | NDTF equity securities | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	51
Duke Energy Carolinas | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,154	2,484
Debt securities, available-for-sale	1,193	1,069
Duke Energy Carolinas | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	227	149
Duke Energy Carolinas | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	966	920
Progress Energy
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,247
Derivative assets	7	4
Total assets	3,913	3,221
Derivative liabilities	(65)	(44)
Net assets (liabilities)	3,825	3,177
Progress Energy | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3,178	2,435
Net assets (liabilities)	3,178	2,435
Progress Energy | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7	4
Total assets	735	786
Derivative liabilities	(65)	(44)
Net assets (liabilities)	647	742
Progress Energy | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,530	1,991
Progress Energy | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,530	1,991
Progress Energy | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,507	1,991
Debt securities, available-for-sale	1,276	1,162
Derivative liabilities	(23)
Progress Energy | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	599	427
Progress Energy | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	677	735
Derivative liabilities	(23)
Progress Energy | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	100	64
Progress Energy | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	49	17
Progress Energy | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	51	47
Duke Energy Progress
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	921
Derivative assets		4
Total assets	3,053	2,504
Derivative liabilities	(49)	(27)
Net assets (liabilities)	3,004	2,477
Duke Energy Progress | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,376	1,888
Net assets (liabilities)	2,376	1,888
Duke Energy Progress | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		4
Total assets	677	616
Derivative liabilities	(49)	(27)
Net assets (liabilities)	628	589
Duke Energy Progress | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,077	1,588
Duke Energy Progress | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,077	1,588
Duke Energy Progress | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,077	1,588
Debt securities, available-for-sale	974	906
Duke Energy Progress | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	297	294
Duke Energy Progress | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	677	612
Duke Energy Progress | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	2	6
Duke Energy Progress | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	2	6
Duke Energy Florida
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	326
Derivative assets	7
Total assets	817	707
Derivative liabilities	(1)	(9)
Net assets (liabilities)	793	698
Duke Energy Florida | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	759	537
Net assets (liabilities)	759	537
Duke Energy Florida | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7
Total assets	58	170
Derivative liabilities	(1)	(9)
Net assets (liabilities)	34	161
Duke Energy Florida | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	453	403
Duke Energy Florida | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	453	403
Duke Energy Florida | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	430	403
Debt securities, available-for-sale	302	256
Derivative liabilities	(23)
Duke Energy Florida | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	302	133
Duke Energy Florida | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale		123
Derivative liabilities	(23)
Duke Energy Florida | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	55	48
Duke Energy Florida | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	4	1
Duke Energy Florida | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	51	47
Duke Energy Indiana
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	81	67
Debt securities, available-for-sale	44
Derivative assets	13	23
Total assets	138	131
Derivative liabilities	(1)
Net assets (liabilities)	137	131
Duke Energy Indiana | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	1
Total assets	83	68
Derivative liabilities	(1)
Net assets (liabilities)	82	68
Duke Energy Indiana | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	44	41
Net assets (liabilities)	44	41
Duke Energy Indiana | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	11	22
Total assets	11	22
Net assets (liabilities)	11	22
Duke Energy Indiana | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	81	67
Debt securities, available-for-sale	44	41
Duke Energy Indiana | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	81	67
Duke Energy Indiana | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	44	41
Piedmont
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1	3
Derivative liabilities	(117)	(141)
Net assets (liabilities)	(116)	(138)
Piedmont | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1	3
Net assets (liabilities)	1	3
Piedmont | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(117)	(141)
Net assets (liabilities)	$ (117)	$ (141)

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Unobservable Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Derivatives (net)
Balance at beginning of period	$ (113)	$ (114)
Purchases	37	57
Settlements	(44)	(57)
Total gains (losses) included on the Consolidated Balance Sheet	18	1
Ending balance	(102)	(113)
Duke Energy Indiana
Derivatives (net)
Balance at beginning of period	22	27
Purchases	28	50
Settlements	(36)	(53)
Total gains (losses) included on the Consolidated Balance Sheet	(3)	(2)
Ending balance	11	22
Piedmont
Derivatives (net)
Balance at beginning of period	(141)	(142)
Total gains (losses) and settlements	24	1
Ending balance	$ (117)	$ (141)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) $ in Millions	Dec. 31, 2019USD ($)$ / MWh$ / MMBTU	Dec. 31, 2018USD ($)$ / MWh$ / MMBTU	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) | $	$ (102)	$ (113)	$ (114)
Duke Energy Ohio | FTR price – per MWh | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) | $	$ 4	$ 6
Duke Energy Ohio | FTR price – per MWh | Minimum | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MWh	0.59	1.19
Duke Energy Ohio | FTR price – per MWh | Maximum | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MWh	3.47	4.59
Duke Energy Ohio | FTR price – per MWh | Weighted Average [Member] | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MWh	2.07
Duke Energy Indiana
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) | $	$ 11	$ 22	27
Duke Energy Indiana | FTR price – per MWh | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) | $	$ 11	$ 22
Duke Energy Indiana | FTR price – per MWh | Minimum | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MWh	(0.66)	(2.07)
Duke Energy Indiana | FTR price – per MWh | Maximum | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MWh	9.24	8.27
Duke Energy Indiana | FTR price – per MWh | Weighted Average [Member] | RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MWh	1.15
Piedmont
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) | $	$ (117)	$ (141)	$ (142)
Piedmont | Forward natural gas curves – price per MMBtu | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) | $	$ (117)	$ (141)
Piedmont | Forward natural gas curves – price per MMBtu | Minimum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MMBTU	1.59	1.87
Piedmont | Forward natural gas curves – price per MMBtu | Maximum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MMBTU	2.46	2.95
Piedmont | Forward natural gas curves – price per MMBtu | Weighted Average [Member] | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) | $ / MMBTU	1.91

Fair Value Measurements (Other

Fair Value Measurements (Other Fair Value Disclosures) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ 58,126	$ 54,529
Long-term debt, fair value	63,062	54,534
Unamortized debt discount and premium, net	1,500	1,600
Duke Energy Carolinas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	11,900	10,939
Long-term debt, fair value	13,516	11,471
Progress Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	19,634	18,911
Long-term debt, fair value	22,291	19,885
Duke Energy Progress
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	9,058	8,204
Long-term debt, fair value	9,934	8,300
Duke Energy Florida
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	7,987	7,321
Long-term debt, fair value	9,131	7,742
Duke Energy Ohio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	2,619	2,165
Long-term debt, fair value	2,964	2,239
Duke Energy Indiana
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	4,057	3,782
Long-term debt, fair value	4,800	4,158
Piedmont
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	2,384	2,138
Long-term debt, fair value	$ 2,642	$ 2,180

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
FES
Variable Interest Entity [Line Items]
Power Purchase Participation Rate	4.85%
Financial guarantee | ACP
Variable Interest Entity [Line Items]
Maximum potential amount of future payments associated with guarantees		$ 827,000,000
Outstanding borrowings under the credit facility, percent		47.00%
VIE
Variable Interest Entity [Line Items]
Financial support		$ 0	$ 0	$ 0
VIE | CRC
Variable Interest Entity [Line Items]
Percent of proceeds received as cash		75.00%
Percent of proceeds received as subordinated note		25.00%
Minimum Equity Balance required by Cinergy Receivables		$ 3,000,000
VIE, Not Primary Beneficiary | CRC | Duke Energy Ohio
Variable Interest Entity [Line Items]
Fixed interest rate added to LIBOR to compute variable rate		1.00%
VIE, Not Primary Beneficiary | OVEC | Duke Energy Ohio
Variable Interest Entity [Line Items]
VIE Ownership interest		9.00%

Variable Interest Entities (Sch

Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Long-Term Debt	$ 54,985	$ 51,123
Duke Energy Carolinas
Variable Interest Entity [Line Items]
Long-Term Debt	11,142	10,633
Duke Energy Progress
Variable Interest Entity [Line Items]
Long-Term Debt	7,902	7,451
Duke Energy Florida
Variable Interest Entity [Line Items]
Long-Term Debt	$ 7,416	7,051
CRC | VIE
Variable Interest Entity [Line Items]
Expiration date	Dec. 1, 2020
Facility Size	$ 350
Long-Term Debt	350	325
Restricted Receivables	$ 522	564
DERF | Duke Energy Carolinas | VIE
Variable Interest Entity [Line Items]
Expiration date	Dec. 1, 2022
Facility Size	$ 475
Long-Term Debt	474	450
Restricted Receivables	$ 642	699
DEPR | Duke Energy Progress | VIE
Variable Interest Entity [Line Items]
Expiration date	Feb. 1, 2021
Facility Size	$ 325
Long-Term Debt	325	300
Restricted Receivables	$ 489	547
DEFR | Duke Energy Florida | VIE
Variable Interest Entity [Line Items]
Expiration date	Apr. 1, 2021
Facility Size	$ 250
Long-Term Debt	250	225
Restricted Receivables	$ 336	$ 357

Variable Interest Entities (Con

Variable Interest Entities (Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory Assets: Current	$ 1,796	$ 2,005
Current Assets: Other	764	1,049
Property, Plant and Equipment: Cost	147,654	134,458
Accumulated depreciation and amortization	(45,773)	(43,126)
Other Noncurrent Assets: Regulatory assets	13,222	13,617
Other Noncurrent Assets: Other	3,289	2,935
Current Liabilities: Other	2,367	2,085
Current maturities of long-term debt	3,141	3,406
Long-Term Debt	54,985	51,123
Asset retirement obligations	12,437	9,548
Other Noncurrent Liabilities: Other	1,581	1,650
Duke Energy Florida
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory Assets: Current	419	434
Current Assets: Other	58	46
Property, Plant and Equipment: Cost	20,457	18,792
Accumulated depreciation and amortization	(5,236)	(4,968)
Other Noncurrent Assets: Regulatory assets	2,194	2,454
Other Noncurrent Assets: Other	311	311
Current Liabilities: Other	415	406
Current maturities of long-term debt	571	270
Long-Term Debt	7,416	7,051
Asset retirement obligations	578	586
Other Noncurrent Liabilities: Other	136	93
DEFPF | Duke Energy Florida | VIE
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	5	5
Regulatory Assets: Current	52	52
Current Assets: Other	39	39
Other Noncurrent Assets: Regulatory assets	989	1,041
Current Liabilities: Other	10	10
Current maturities of long-term debt	54	53
Long-Term Debt	1,057	1,111
Commercial Renewables | VIE
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Current Assets: Other	203	123
Property, Plant and Equipment: Cost	5,747	4,007
Accumulated depreciation and amortization	(1,041)	(698)
Other Noncurrent Assets: Other	106	261
Current maturities of long-term debt	162	174
Long-Term Debt	1,541	1,587
Asset retirement obligations	127	106
Other Noncurrent Liabilities: Other	$ 228	$ 212

Variable Interest Entities (S_2

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,936	$ 1,409	$ 1,175
Other Noncurrent Assets: Other	3,289	2,935
Current Liabilities: Other	2,367	2,085
Deferred income taxes	8,878	7,806
Other Noncurrent Liabilities: Other	1,581	1,650
Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables from affiliated companies	92	114
Other Noncurrent Assets: Other	52	41
Current Liabilities: Other	75	74
Deferred income taxes	922	817
Other Noncurrent Liabilities: Other	94	93
Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables from affiliated companies	79	122
Other Noncurrent Assets: Other	234	194
Current Liabilities: Other	112	107
Deferred income taxes	1,150	1,009
Other Noncurrent Liabilities: Other	18	16
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Receivables from affiliated companies	(1)
Investments in equity method unconsolidated affiliates	1,479	1,060
Total assets	1,478	1,060
Taxes accrued	(1)	(1)
Current Liabilities: Other	4	4
Deferred income taxes	59	21
Other Noncurrent Liabilities: Other	11	12
Total liabilities	73	36
Net assets (liabilities) of non-consolidated VIEs	1,405	1,024
VIE, Not Primary Beneficiary | Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables from affiliated companies	64	93
Total assets	64	93
Net assets (liabilities) of non-consolidated VIEs	64	93
VIE, Not Primary Beneficiary | Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables from affiliated companies	77	118
Total assets	77	118
Net assets (liabilities) of non-consolidated VIEs	77	118
VIE, Not Primary Beneficiary | Pipeline Investments
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	1,179	822
Total assets	1,179	822
Taxes accrued	(1)	(1)
Deferred income taxes	59	21
Total liabilities	58	20
Net assets (liabilities) of non-consolidated VIEs	1,121	802
VIE, Not Primary Beneficiary | Commercial Renewables
Variable Interest Entity [Line Items]
Receivables from affiliated companies	(1)
Investments in equity method unconsolidated affiliates	300	190
Total assets	299	190
Net assets (liabilities) of non-consolidated VIEs	299	190
VIE, Not Primary Beneficiary | Other VIEs
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates		48
Total assets		48
Current Liabilities: Other	4	4
Other Noncurrent Liabilities: Other	11	12
Total liabilities	15	16
Net assets (liabilities) of non-consolidated VIEs	(15)	$ 32
VIE, Not Primary Beneficiary | Pioneer
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 57
VIE Ownership interest	50.00%

Variable Interest Entities (S_3

Variable Interest Entities (Schedule of Non-Consolidated VIE Pipeline Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,936	$ 1,409	$ 1,175
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,479	1,060
ACP | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIE Ownership interest	47.00%
Investments in equity method unconsolidated affiliates	$ 1,179	797
Constitution | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIE Ownership interest	24.00%
Investments in equity method unconsolidated affiliates		25
Pipeline Investments | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,179	822
Gas Utilities and Infrastructure
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	1,388	1,003	$ 763
Gas Utilities and Infrastructure | Constitution | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
OTTI impairment loss	$ 25	$ 55

Variable Interest Entities (Fai

Variable Interest Entities (Fair Value Assumptions) (Details) - CRC - VIE, Not Primary Beneficiary	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Duke Energy Ohio
Variable Interest Entity [Line Items]
Anticipated credit loss ratio	0.60%	0.50%
Discount rate	3.30%	3.00%
Receivable turnover rate	13.40%	13.50%
Duke Energy Indiana
Variable Interest Entity [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	3.30%	3.00%
Receivable turnover rate	11.50%	11.00%

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold) (Details) - VIE, Not Primary Beneficiary - CRC - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables sold	$ 253	$ 269
Less: Retained interests	64	93
Net receivables sold	189	176
Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables sold	307	336
Less: Retained interests	77	118
Net receivables sold	$ 230	$ 218

Variable Interest Entities (Sal

Variable Interest Entities (Sales and Cash Flows) (Details) - VIE, Not Primary Beneficiary - CRC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables sold	$ 1,979	$ 1,987	$ 1,879
Loss recognized on sale	14	13	10
Cash proceeds from receivables sold	1,993	1,967	1,865
Collection fees received	1	1	1
Return received on retained interests	6	6	3
Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables sold	2,837	2,842	2,711
Loss recognized on sale	17	16	12
Cash proceeds from receivables sold	2,860	2,815	2,694
Collection fees received	1	1	1
Return received on retained interests	$ 9	$ 9	$ 7

Revenue (Remaining Performance

Revenue (Remaining Performance Obligations) (Details) $ in Millions	Dec. 31, 2019USD ($)
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 121
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 92
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 87
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 44
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 45
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 58
Progress Energy | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	447
Duke Energy Progress | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 8
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Progress | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 8
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Progress | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 8
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Progress | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 8
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Progress | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 8
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Progress | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 40
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 113
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 84
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 79
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 36
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 37
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 58
Duke Energy Florida | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	407
Duke Energy Indiana | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 10
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Indiana | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 5
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Indiana | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Indiana | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Indiana | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Duke Energy Indiana | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 15
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 69
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 64
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 64
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 61
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 58
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 372
Piedmont | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 688

Revenue (Disaggregation of Reve

Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 24,348	$ 23,757
Revenue from sources other than contracts with customers									731	764
Total operating revenues	$ 6,103	$ 6,940	$ 5,873	$ 6,163	$ 6,115	$ 6,628	$ 5,643	$ 6,135	25,079	24,521	$ 23,565
Other
Disaggregation of Revenue [Line Items]
Total operating revenues									1,037	1,081	1,239
Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									22,347	21,729
Total operating revenues									22,798	22,242	21,300
Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									9,863	9,587
Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									6,431	6,127
Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									3,071	2,974
Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,212	2,324
Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									770	717
Total operating revenues									855	915	1,050
Gas Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,754	1,800
Total operating revenues									1,770	1,783	1,743
Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									976	1,000
Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									508	514
Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									141	147
Gas Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									129	139
Total operating revenues									84	64	104
Commercial Renewables
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									223	209
Total operating revenues									487	477	460
Commercial Renewables | Other
Disaggregation of Revenue [Line Items]
Total operating revenues									98	102	85
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									24	19
Total operating revenues									24	19	62
Duke Energy Carolinas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									7,241	7,108
Revenue from sources other than contracts with customers									154	192
Total operating revenues	1,776	2,162	1,713	1,744	1,775	2,090	1,672	1,763	7,395	7,300	7,302
Duke Energy Carolinas | Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									7,241	7,108
Duke Energy Carolinas | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									3,044	2,981
Duke Energy Carolinas | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,244	2,119
Duke Energy Carolinas | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,215	1,180
Duke Energy Carolinas | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									462	508
Duke Energy Carolinas | Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									276	320
Progress Energy
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									10,883	10,462
Revenue from sources other than contracts with customers									319	266
Total operating revenues	2,644	3,242	2,744	2,572	2,609	3,045	2,498	2,576	11,202	10,728	9,783
Progress Energy | Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									10,883	10,462
Progress Energy | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									4,998	4,785
Progress Energy | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,935	2,809
Progress Energy | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									934	904
Progress Energy | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,468	1,462
Progress Energy | Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									548	502
Duke Energy Progress
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,785	5,564
Revenue from sources other than contracts with customers									172	135
Total operating revenues	1,398	1,688	1,387	1,484	1,366	1,582	1,291	1,460	5,957	5,699	5,129
Duke Energy Progress | Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,785	5,564
Duke Energy Progress | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,144	2,019
Duke Energy Progress | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,368	1,280
Duke Energy Progress | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									675	642
Duke Energy Progress | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,281	1,303
Duke Energy Progress | Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									317	320
Duke Energy Florida
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,098	4,898
Revenue from sources other than contracts with customers									133	123
Total operating revenues	1,244	1,548	1,353	1,086	1,241	1,462	1,203	1,115	5,231	5,021	4,646
Duke Energy Florida | Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									5,098	4,898
Duke Energy Florida | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,854	2,766
Duke Energy Florida | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,567	1,529
Duke Energy Florida | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									259	262
Duke Energy Florida | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									187	159
Duke Energy Florida | Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									231	182
Duke Energy Ohio
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,940	1,930
Revenue from sources other than contracts with customers										27
Total operating revenues	487	489	433	531	505	469	459	524	1,940	1,957	1,923
Duke Energy Ohio | Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,457	1,426
Duke Energy Ohio | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									733	743
Duke Energy Ohio | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									451	422
Duke Energy Ohio | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									147	131
Duke Energy Ohio | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									46	57
Duke Energy Ohio | Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									80	73
Duke Energy Ohio | Gas Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									483	503
Duke Energy Ohio | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									315	331
Duke Energy Ohio | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									130	135
Duke Energy Ohio | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									19	18
Duke Energy Ohio | Gas Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									19	19
Duke Energy Ohio | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers										1
Duke Energy Indiana
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,987	3,003
Revenue from sources other than contracts with customers									17	56
Total operating revenues	715	807	714	768	771	819	738	731	3,004	3,059	3,047
Duke Energy Indiana | Electric Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,987	3,003
Duke Energy Indiana | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,087	1,076
Duke Energy Indiana | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | General
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									802	778
Duke Energy Indiana | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									774	760
Duke Energy Indiana | Electric Utilities and Infrastructure | Electric Utilities and Infrastructure | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									235	298
Duke Energy Indiana | Electric Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									89	91
Piedmont
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,322	1,349
Revenue from sources other than contracts with customers									59	26
Total operating revenues	$ 425	$ 168	$ 209	$ 579	$ 435	$ 172	$ 215	$ 553	1,381	1,375	$ 1,328
Piedmont | Gas Utilities and Infrastructure
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									1,322	1,349
Piedmont | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									661	669
Piedmont | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									378	378
Piedmont | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									122	128
Piedmont | Gas Utilities and Infrastructure | Gas Utilities and Infrastructure | Power Generation [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									51	54
Piedmont | Gas Utilities and Infrastructure | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 110	$ 120

Revenue (Unbilled Revenues) (De

Revenue (Unbilled Revenues) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 843	$ 896
Duke Energy Carolinas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	298	313
Progress Energy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	217	244
Duke Energy Progress
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	122	148
Duke Energy Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	95	96
Duke Energy Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	1	2
Duke Energy Ohio | CRC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	82	86
Duke Energy Indiana
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	16	23
Duke Energy Indiana | CRC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	115	128
Piedmont
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 78	$ 73

Stockholders' Equity (Earnings

Stockholders' Equity (Earnings Per Share Data) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Income from continuing operations available to Duke Energy common stockholders excluding impact of participating securities and including accumulated preferred stock dividends									$ 3,694	$ 2,642	$ 3,059
Weighted average common shares outstanding – basic and diluted									729	708	700
EPS from continuing operations available to Duke Energy common stockholders, Basic and diluted (in usd per share)	$ 0.89	$ 1.82	$ 1.12	$ 1.24	$ 0.62	$ 1.51	$ 0.72	$ 0.88	$ 5.07	$ 3.73	$ 4.37
Potentially dilutive items excluded from the calculation(in shares)									2	2	2
Dividends declared per share (usd per share)									$ 3.75	$ 3.64	$ 3.49
Dividends declared on Series A preferred stock per depositary share (in usd per share)									$ 1.03

Stockholders' Equity (Common St

Stockholders' Equity (Common Stock) (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended						2 Months Ended	12 Months Ended
	Nov. 30, 2019	Apr. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Feb. 28, 2018	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Forward Contract Indexed to Issuer's Equity [Line Items]
Maximum value of shares to be issued under ATM program	$ 1,500,000,000					$ 1,000,000,000
Shares Issue, Under Net Share Settle Election								1,600
Stock Issued During Period, Shares, Dividend Reinvestment Plan								1,800	2,200
Stock Issued During Period, Value, Dividend Reinvestment Plan								$ 160,000,000	$ 174,000,000
ATM
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered		1,100	1,100				1,600
Settlement Alternatives, Shares				2,600					2,600
Proceeds from Issuance or Sale of Equity				$ 195,000,000
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share	$ 85.99	$ 88.82	$ 89.83				$ 86.23
Tranche 1
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered					1,300
Tranche 2
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered					1,300
Equity forwards
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered	28,750									21,300
Settlement Alternatives, Shares										21,300
Proceeds from Issuance or Sale of Equity				$ 766,000,000	$ 781,000,000			$ 331,000,000
Shares issued (in shares)				10,600	10,600			3,800	10,600

Stockholders' Equity (Preferred

Stockholders' Equity (Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 16, 2024	Sep. 12, 2019	Mar. 29, 2019	Dec. 31, 2019	Jun. 15, 2024	Sep. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Net proceeds from Issuance of Preferred Stock and Preference Stock		$ 989	$ 973	$ 1,962
Current maturities of long-term debt				$ 3,141			$ 3,406
Series A Cumulative Redeemable Perpetual Preferred Stock
Class of Stock [Line Items]
Shares issued (in shares)			40,000,000
Preferred stock, issue price (in usd per share)			$ 25
Liquidation preference per share (in usd per share)			$ 25
Cumulative annual dividend rate			5.75%
Redemption price (in usd per share)				$ 25.50
Series B Fixed-Rate Reset Cumulative Redeemable Perpetual Preferred Stock
Class of Stock [Line Items]
Shares issued (in shares)		1,000,000
Preferred stock, issue price (in usd per share)		$ 1,000
Liquidation preference per share (in usd per share)		$ 1,000
Cumulative annual dividend rate		4.875%
Redemption price (in usd per share)		$ 1,020
Forecast
Class of Stock [Line Items]
Redemption price (in usd per share)					$ 25
Forecast | Series B Fixed-Rate Reset Cumulative Redeemable Perpetual Preferred Stock
Class of Stock [Line Items]
Cumulative annual dividend rate	3.388%
Unsecured Debt | Senior notes due September 2019 | Parent Company
Class of Stock [Line Items]
Current maturities of long-term debt						$ 500

Severance (Narrative) (Details)

Severance (Narrative) (Details) - employee	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Number of eligible employees	140	1,900	100

Severance (Expenses) (Details)

Severance (Expenses) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 187	$ 16	$ 187	$ 15
Duke Energy Carolinas
Restructuring Cost and Reserve [Line Items]
Severance expense	102	8	102	2
Progress Energy
Restructuring Cost and Reserve [Line Items]
Severance expense	69	6	69	2
Duke Energy Progress
Restructuring Cost and Reserve [Line Items]
Severance expense	52	3	52	1
Duke Energy Florida
Restructuring Cost and Reserve [Line Items]
Severance expense	17	3	17	1
Duke Energy Ohio
Restructuring Cost and Reserve [Line Items]
Severance expense	6		6
Duke Energy Indiana
Restructuring Cost and Reserve [Line Items]
Severance expense	7	1	7	1
Piedmont
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 2	$ 1	$ 2	$ 9

Severance (Rollforward) (Detail

Severance (Rollforward) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 205
Provision/adjustments	24
Cash reductions	(188)
Balance, end of period	41
Duke Energy Carolinas
Restructuring Reserve [Roll Forward]
Balance, beginning of period	100
Provision/adjustments	4
Cash reductions	(93)
Balance, end of period	11
Progress Energy
Restructuring Reserve [Roll Forward]
Balance, beginning of period	51
Provision/adjustments	11
Cash reductions	(49)
Balance, end of period	13
Duke Energy Progress
Restructuring Reserve [Roll Forward]
Balance, beginning of period	41
Provision/adjustments	2
Cash reductions	(37)
Balance, end of period	6
Duke Energy Florida
Restructuring Reserve [Roll Forward]
Balance, beginning of period	9
Provision/adjustments	10
Cash reductions	(12)
Balance, end of period	7
Duke Energy Ohio
Restructuring Reserve [Roll Forward]
Balance, beginning of period	2
Provision/adjustments	1
Cash reductions	(2)
Balance, end of period	1
Duke Energy Indiana
Restructuring Reserve [Roll Forward]
Balance, beginning of period	2
Provision/adjustments	1
Cash reductions	(1)
Balance, end of period	$ 2

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for awards to employees and outside directors	10
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant date fair value of shares vested	$ 49,000,000	$ 43,000,000	$ 42,000,000
Unrecognized compensation cost	$ 30,000,000
Unrecognized compensation cost, period of recognition, years	23 months
RSU awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Total grant date fair value of shares vested	$ 23,000,000	$ 13,000,000	$ 0
Unrecognized compensation cost	$ 27,000,000
Unrecognized compensation cost, period of recognition, years	22 months
Risk Free Interest Rate	2.50%
Expected Volatility Rate	14.80%
Performance awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent	200.00%
Piedmont | RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Piedmont | Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	$ 65	$ 56	$ 43
Pretax stock-based compensation cost	89	78	68
Stock-based compensation costs capitalized	5	5	4
Stock-based compensation expense	84	73	64
Tax benefit associated with stock-based compensation expense	19	17	25
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	44	43	41
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	45	35	27
Duke Energy Carolinas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	24	20	15
Progress Energy
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	24	21	16
Duke Energy Progress
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	15	13	10
Duke Energy Florida
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	9	8	6
Duke Energy Ohio
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	5	4	3
Duke Energy Indiana
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	6	5	4
Piedmont
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	$ 3	$ 3	$ 3

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of Stock Awards Outstanding) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
RSU awards
Schedule Of Shares Awarded [Abstract]
Shares granted (in thousands)	571	649	583
Fair value (in millions)	$ 51	$ 49	$ 47
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of period	1,153
Granted	571	649	583
Vested	(631)
Forfeited	(83)
Outstanding at end of period	1,010	1,153
Stock awards expected to vest	951
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average fair value at beginning of period	$ 77
Granted	89
Vested	77
Forfeited	82
Weighted average fair value at end of period	83	$ 77
Weighted average fair value of awards expected to vest	$ 83
Performance awards
Schedule Of Shares Awarded [Abstract]
Shares granted (in thousands)	320	372	461
Fair value (in millions)	$ 27	$ 27	$ 37
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of period	1,117
Granted	320	372	461
Vested	(310)
Forfeited	(18)
Outstanding at end of period	1,109	1,117
Stock awards expected to vest	1,080
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average fair value at beginning of period	$ 77
Granted	86
Vested	75
Forfeited	81
Weighted average fair value at end of period	80	$ 77
Weighted average fair value of awards expected to vest	$ 80

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Defined Benefit Plan Disclosure [Line Items]
Maximum years of participation	35 years
Impact of plan conversion on next year's net periodic benefit cost	$ 33
Master Trust
Defined Benefit Plan Disclosure [Line Items]
Target allocation	100.00%
Expected long-term rate of return on plan assets	6.85%
Fair value of securities on loan	$ 351	$ 154
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 77	141	$ 19
Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	12 years
Defined Benefit Plan, Benefit Obligation	$ 8,321	7,869	$ 8,448
Accumulated Benefit Obligation at measurement date	$ 8,262	$ 7,818
Expected long-term rate of return on plan assets	6.85%	6.50%	6.75%
Employer contributions	$ 77	$ 141
Benefits paid	731	567
Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	318
Accumulated Benefit Obligation at measurement date	318
Employer contributions	25
Benefits paid	$ 25
Pension Plan | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Master trust allocation percentage	98.00%
Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	8 years
Defined Benefit Plan, Benefit Obligation	$ 723	$ 728	$ 813
Expected long-term rate of return on plan assets	6.85%	6.50%	6.50%
Employer contributions	$ 60
Benefits paid	$ 83	$ 86
Other Post-Retirement Benefit Plans | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Master trust allocation percentage	2.00%
Duke Energy Carolinas | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 7	46	$ 0
Duke Energy Carolinas | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	12 years
Defined Benefit Plan, Benefit Obligation	$ 1,923	1,954	2,029
Accumulated Benefit Obligation at measurement date	1,923	1,954
Employer contributions	7	46
Benefits paid	265	159
Duke Energy Carolinas | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	15
Accumulated Benefit Obligation at measurement date	15
Employer contributions	2
Benefits paid	$ 2
Duke Energy Carolinas | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	8 years
Defined Benefit Plan, Benefit Obligation	$ 175	174	189
Employer contributions	11
Benefits paid	19	18
Progress Energy | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 57	45	0
Progress Energy | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	12 years
Defined Benefit Plan, Benefit Obligation	$ 2,608	2,433	2,637
Accumulated Benefit Obligation at measurement date	2,578	2,404
Employer contributions	57	45
Benefits paid	191	143
Progress Energy | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	110
Accumulated Benefit Obligation at measurement date	110
Employer contributions	9
Benefits paid	$ 9
Progress Energy | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	6 years
Defined Benefit Plan, Benefit Obligation	$ 303	303	342
Employer contributions	26
Benefits paid	32	35
Duke Energy Progress | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 4	25	0
Duke Energy Progress | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	13 years
Defined Benefit Plan, Benefit Obligation	$ 1,170	1,125	1,211
Accumulated Benefit Obligation at measurement date	1,170	1,125
Employer contributions	4	25
Benefits paid	112	70
Duke Energy Progress | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	32
Accumulated Benefit Obligation at measurement date	32
Employer contributions	3
Duke Energy Progress | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	168	166	184
Employer contributions	13
Benefits paid	17	19
Duke Energy Florida | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 53	20	0
Duke Energy Florida | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	12 years
Defined Benefit Plan, Benefit Obligation	$ 1,424	1,295	1,410
Accumulated Benefit Obligation at measurement date	1,392	1,265
Employer contributions	53	20
Benefits paid	78	72
Duke Energy Florida | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	45
Accumulated Benefit Obligation at measurement date	45
Employer contributions	3
Benefits paid	$ 3
Duke Energy Florida | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Defined Benefit Plan, Benefit Obligation	$ 135	137	156
Employer contributions	13
Benefits paid	15	16
Duke Energy Ohio | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 2	0	4
Duke Energy Ohio | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	13 years
Defined Benefit Plan, Benefit Obligation	$ 481	435	479
Accumulated Benefit Obligation at measurement date	471	425
Employer contributions	2	0
Benefits paid	30	37
Duke Energy Ohio | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	4
Accumulated Benefit Obligation at measurement date	4
Benefits paid	$ 3
Duke Energy Ohio | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Defined Benefit Plan, Benefit Obligation	$ 29	29	30
Employer contributions	2
Benefits paid	3	2
Duke Energy Indiana | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 2	8	0
Duke Energy Indiana | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	13 years
Defined Benefit Plan, Benefit Obligation	$ 693	618	669
Accumulated Benefit Obligation at measurement date	686	614
Employer contributions	2	8
Benefits paid	46	55
Duke Energy Indiana | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	3
Accumulated Benefit Obligation at measurement date	$ 3
Duke Energy Indiana | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	6 years
Defined Benefit Plan, Benefit Obligation	$ 64	67	78
Employer contributions	9
Benefits paid	$ 11	12
Piedmont
Defined Benefit Plan Disclosure [Line Items]
Vesting period	3 years
Term	3 years
Piedmont | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 1	0	11
Piedmont | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Defined Benefit Plan, Benefit Obligation	$ 292	264	313
Accumulated Benefit Obligation at measurement date	292	264
Employer contributions	1	0
Benefits paid	20	33
Piedmont | Pension Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	4
Accumulated Benefit Obligation at measurement date	$ 4
Piedmont | Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	6 years
Defined Benefit Plan, Benefit Obligation	$ 30	30	$ 32
Employer contributions	0
Benefits paid	1	$ 2
Liability Hedging Assets | Pension Plan | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Target allocation				58.00%
Return Seeking Assets | Pension Plan | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Target allocation				42.00%
Minimum | Pension Plan | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets			6.50%
Retirement plan settled
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	94
Retirement plan settled | Duke Energy Carolinas
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	53
Retirement plan settled | Progress Energy
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	26
Retirement plan settled | Duke Energy Progress
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	20
Retirement plan settled | Duke Energy Florida
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	6
Retirement plan settled | Duke Energy Ohio
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	2
Retirement plan settled | Duke Energy Indiana
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	4
Retirement plan settled | Piedmont
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	$ 8

Employee Benefit Plans (Contrib

Employee Benefit Plans (Contributions to Defined Benefit Pension Plans) (Details) - Pension Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 77	$ 141	$ 19
Duke Energy Carolinas
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	7	46	0
Progress Energy
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	57	45	0
Duke Energy Progress
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	4	25	0
Duke Energy Florida
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	53	20	0
Duke Energy Ohio
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	2	0	4
Duke Energy Indiana
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	2	8	0
Piedmont
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 1	$ 0	$ 11

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Amortization of Regulatory Asset	$ 4	$ 5	$ 7
Pension Plan | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	158	182
Service cost	150	174	159
Interest cost	317	299	328
Expected return on plan assets	(567)	(559)	(545)
Amortization of actuarial loss (gain)	108	132	146
Amortization of prior service cost (credit)	(32)	(32)	(24)
Settlement charge			12
Other	6		8
Net periodic costs	(10)	22	84
Pension Plan | Duke Energy Carolinas | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	49	58
Service cost	47	56	48
Interest cost	75	72	79
Expected return on plan assets	(147)	(147)	(142)
Amortization of actuarial loss (gain)	24	29	31
Amortization of prior service cost (credit)	(8)	(8)	(8)
Settlement charge			0
Other	2		2
Net periodic costs	(5)	4	10
Pension Plan | Progress Energy | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	46	51
Service cost	43	49	45
Interest cost	100	94	100
Expected return on plan assets	(178)	(178)	(167)
Amortization of actuarial loss (gain)	39	44	52
Amortization of prior service cost (credit)	(3)	(3)	(3)
Settlement charge			0
Other	1		2
Net periodic costs	5	8	29
Pension Plan | Duke Energy Progress | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	26	29
Service cost	25	28	26
Interest cost	45	43	47
Expected return on plan assets	(88)	(85)	(82)
Amortization of actuarial loss (gain)	15	21	23
Amortization of prior service cost (credit)	(2)	(2)	(2)
Settlement charge			0
Other	1		1
Net periodic costs	(3)	6	13
Pension Plan | Duke Energy Florida | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	20	22
Service cost	18	21	19
Interest cost	54	50	53
Expected return on plan assets	(89)	(91)	(85)
Amortization of actuarial loss (gain)	24	23	29
Amortization of prior service cost (credit)	(1)	(1)	(1)
Settlement charge			0
Other	0		1
Net periodic costs	8	3	16
Pension Plan | Duke Energy Ohio
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Amortization of Regulatory Asset	2	2	3
Pension Plan | Duke Energy Ohio | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	4	5
Service cost	4	5	4
Interest cost	18	17	18
Expected return on plan assets	(28)	(28)	(27)
Amortization of actuarial loss (gain)	4	5	5
Amortization of prior service cost (credit)	0	0	(1)
Settlement charge			0
Other	2		0
Net periodic costs	0	(1)	(1)
Pension Plan | Duke Energy Indiana | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	9	11
Service cost	8	10	9
Interest cost	26	23	26
Expected return on plan assets	(43)	(42)	(42)
Amortization of actuarial loss (gain)	8	10	12
Amortization of prior service cost (credit)	(2)	(2)	(2)
Settlement charge			0
Other	0		1
Net periodic costs	(2)	0	4
Pension Plan | Piedmont | Qualified Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	5	7
Service cost	5	7	10
Interest cost	10	11	14
Expected return on plan assets	(22)	(22)	(24)
Amortization of actuarial loss (gain)	8	11	11
Amortization of prior service cost (credit)	(9)	(10)	(2)
Settlement charge			12
Other	0		1
Net periodic costs	(8)	(3)	22
Other Post-Retirement Benefit Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	4	6	4
Interest cost	30	28	34
Expected return on plan assets	(12)	(13)	(14)
Amortization of actuarial loss (gain)	4	6	10
Amortization of prior service cost (credit)	(19)	(19)	(115)
Curtailment credit			(30)
Net periodic costs	7	8	(111)
Amortization of Regulatory Asset	6	7	7
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1	1
Interest cost	7	7	8
Expected return on plan assets	(7)	(8)	(8)
Amortization of actuarial loss (gain)	2	3	(2)
Amortization of prior service cost (credit)	(5)	(5)	(10)
Curtailment credit			(4)
Net periodic costs	(2)	(2)	(15)
Other Post-Retirement Benefit Plans | Progress Energy
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1	0
Interest cost	12	12	13
Expected return on plan assets	0	0	0
Amortization of actuarial loss (gain)	1	1	21
Amortization of prior service cost (credit)	(8)	(8)	(84)
Curtailment credit			(16)
Net periodic costs	6	6	(66)
Other Post-Retirement Benefit Plans | Duke Energy Progress
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	0
Interest cost	7	6	7
Expected return on plan assets	0	0	0
Amortization of actuarial loss (gain)	0	1	12
Amortization of prior service cost (credit)	(1)	(1)	(54)
Net periodic costs	6	6	(35)
Other Post-Retirement Benefit Plans | Duke Energy Florida
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1	0
Interest cost	5	6	6
Expected return on plan assets	0	0	0
Amortization of actuarial loss (gain)	1	0	9
Amortization of prior service cost (credit)	(7)	(7)	(30)
Curtailment credit			(16)
Net periodic costs	0	0	(31)
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	1	0
Interest cost	1	1	1
Expected return on plan assets	0	0	0
Amortization of actuarial loss (gain)	0	0	(2)
Amortization of prior service cost (credit)	(1)	(1)	0
Curtailment credit			(2)
Net periodic costs	0	1	(3)
Amortization of Regulatory Asset	2	2	2
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1	0
Interest cost	3	3	3
Expected return on plan assets	0	0	(1)
Amortization of actuarial loss (gain)	4	4	(1)
Amortization of prior service cost (credit)	(1)	(1)	(1)
Curtailment credit			(2)
Net periodic costs	7	7	(2)
Other Post-Retirement Benefit Plans | Piedmont
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	1	1
Interest cost	1	1	1
Expected return on plan assets	(1)	(2)	(2)
Amortization of actuarial loss (gain)	0	0	1
Amortization of prior service cost (credit)	(2)	(2)	0
Curtailment credit			0
Net periodic costs	$ (2)	$ (2)	$ 1

Employee Benefit Plans (Amounts

Employee Benefit Plans (Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive income	[1]	$ (9)	$ 6	$ (3)
Progress Energy
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive income		(2)	(5)	$ (4)
Pension Plan | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(212)	298
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		20	(2)
Amortization of prior year service credit		1	1
Amortization of prior year actuarial losses		(15)	10
Net amount recognized in accumulated other comprehensive income		6	9
Pension Plan | Duke Energy Carolinas | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(156)	170
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Pension Plan | Progress Energy | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(79)	40
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		1	1
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		(2)	(4)
Net amount recognized in accumulated other comprehensive income		(1)	(3)
Pension Plan | Duke Energy Progress | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(59)	31
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Pension Plan | Duke Energy Florida | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(20)	9
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		(1)	0
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		3	0
Net amount recognized in accumulated other comprehensive income		2	0
Pension Plan | Duke Energy Ohio | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		12	10
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Pension Plan | Duke Energy Indiana | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		22	30
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Pension Plan | Piedmont | Qualified Plan
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		0	8
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year service credit		0	0
Amortization of prior year actuarial losses		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(127)	137
Accumulated other comprehensive loss (income)		(152)	154
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	(1)
Amortization of prior year prior service cost		(4)	1
Net amount recognized in accumulated other comprehensive income		(4)	0
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		0	0
Accumulated other comprehensive loss (income)		1	(6)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans | Progress Energy
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(127)	133
Accumulated other comprehensive loss (income)		(149)	149
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans | Duke Energy Progress
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(82)	84
Accumulated other comprehensive loss (income)		(93)	93
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans | Duke Energy Florida
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(45)	49
Accumulated other comprehensive loss (income)		(56)	56
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		0	0
Accumulated other comprehensive loss (income)		(1)	2
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(5)	(5)
Accumulated other comprehensive loss (income)		(4)	3
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		0	0
Other Post-Retirement Benefit Plans | Piedmont
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		0	4
Accumulated other comprehensive loss (income)		3	0
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		0	0
Amortization of prior year prior service cost		0	0
Net amount recognized in accumulated other comprehensive income		$ 0	$ 0
[1]	Tax impacts are insignificant for all periods presented.

Employee Benefit Plans (Project

Employee Benefit Plans (Projected Benefit Obligations Reconciliation of Funded Status to Net Amount Recognized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	$ 77	$ 141	$ 19
Pension Plan | Duke Energy Carolinas
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	7	46	0
Pension Plan | Progress Energy
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	57	45	0
Pension Plan | Duke Energy Progress
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	4	25	0
Pension Plan | Duke Energy Florida
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	53	20	0
Pension Plan | Duke Energy Ohio
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	2	0	4
Pension Plan | Duke Energy Indiana
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	2	8	0
Pension Plan | Piedmont
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions	1	0	11
Pension Plan | Qualified Plan
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	7,869	8,448
Service cost	150	174	159
Interest cost	317	299	328
Actuarial loss (gain)	716	(485)
Transfers	0	0
Benefits paid	(731)	(567)
Obligation at measurement date	8,321	7,869	8,448
Accumulated Benefit Obligation at measurement date	8,262	7,818
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	8,233	9,003
Employer contributions	77	141
Actual return on plan assets	1,331	(344)
Benefits paid	(731)	(567)
Transfers	0	0
Plan assets at measurement date	8,910	8,233	9,003
Funded status of plan	589	364
Pension Plan | Qualified Plan | Duke Energy Carolinas
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,954	2,029
Service cost	47	56	48
Interest cost	75	72	79
Actuarial loss (gain)	101	(44)
Transfers	11	0
Benefits paid	(265)	(159)
Obligation at measurement date	1,923	1,954	2,029
Accumulated Benefit Obligation at measurement date	1,923	1,954
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	2,168	2,372
Employer contributions	7	46
Actual return on plan assets	342	(91)
Benefits paid	(265)	(159)
Transfers	11	0
Plan assets at measurement date	2,263	2,168	2,372
Funded status of plan	340	214
Pension Plan | Qualified Plan | Progress Energy
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	2,433	2,637
Service cost	43	49	45
Interest cost	100	94	100
Actuarial loss (gain)	223	(204)
Transfers	0	0
Benefits paid	(191)	(143)
Obligation at measurement date	2,608	2,433	2,637
Accumulated Benefit Obligation at measurement date	2,578	2,404
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	2,606	2,814
Employer contributions	57	45
Actual return on plan assets	426	(110)
Benefits paid	(191)	(143)
Transfers	0	0
Plan assets at measurement date	2,898	2,606	2,814
Funded status of plan	290	173
Pension Plan | Qualified Plan | Duke Energy Progress
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,125	1,211
Service cost	25	28	26
Interest cost	45	43	47
Actuarial loss (gain)	87	(87)
Transfers	0	0
Benefits paid	(112)	(70)
Obligation at measurement date	1,170	1,125	1,211
Accumulated Benefit Obligation at measurement date	1,170	1,125
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	1,268	1,366
Employer contributions	4	25
Actual return on plan assets	204	(53)
Benefits paid	(112)	(70)
Transfers	0	0
Plan assets at measurement date	1,364	1,268	1,366
Funded status of plan	194	143
Pension Plan | Qualified Plan | Duke Energy Florida
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,295	1,410
Service cost	18	21	19
Interest cost	54	50	53
Actuarial loss (gain)	135	(114)
Transfers	0	0
Benefits paid	(78)	(72)
Obligation at measurement date	1,424	1,295	1,410
Accumulated Benefit Obligation at measurement date	1,392	1,265
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	1,322	1,429
Employer contributions	53	20
Actual return on plan assets	218	(55)
Benefits paid	(78)	(72)
Transfers	0	0
Plan assets at measurement date	1,515	1,322	1,429
Funded status of plan	91	27
Pension Plan | Qualified Plan | Duke Energy Ohio
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	435	479
Service cost	4	5	4
Interest cost	18	17	18
Actuarial loss (gain)	54	(29)
Transfers	0	0
Benefits paid	(30)	(37)
Obligation at measurement date	481	435	479
Accumulated Benefit Obligation at measurement date	471	425
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	405	458
Employer contributions	2	0
Actual return on plan assets	66	(16)
Benefits paid	(30)	(37)
Transfers	0	0
Plan assets at measurement date	443	405	458
Funded status of plan	(38)	(30)
Pension Plan | Qualified Plan | Duke Energy Indiana
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	618	669
Service cost	8	10	9
Interest cost	26	23	26
Actuarial loss (gain)	87	(29)
Transfers	0	0
Benefits paid	(46)	(55)
Obligation at measurement date	693	618	669
Accumulated Benefit Obligation at measurement date	686	614
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	611	684
Employer contributions	2	8
Actual return on plan assets	100	(26)
Benefits paid	(46)	(55)
Transfers	0	0
Plan assets at measurement date	667	611	684
Funded status of plan	(26)	(7)
Pension Plan | Qualified Plan | Piedmont
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	264	313
Service cost	5	7	10
Interest cost	10	11	14
Actuarial loss (gain)	33	(18)
Transfers	0	(16)
Benefits paid	(20)	(33)
Obligation at measurement date	292	264	313
Accumulated Benefit Obligation at measurement date	292	264
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	305	368
Employer contributions	1	0
Actual return on plan assets	49	(14)
Benefits paid	(20)	(33)
Transfers	0	(16)
Plan assets at measurement date	335	305	368
Funded status of plan	43	41
Other Post-Retirement Benefit Plans
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	728	813
Service cost	4	6	4
Interest cost	30	28	34
Plan participants' contributions	16	18
Actuarial loss (gain)	28	(51)
Transfers	0	0
Benefits paid	(83)	(86)
Obligation at measurement date	723	728	813
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	195	225
Employer contributions	60
Actual return on plan assets	32	(8)
Benefits paid	(83)	(86)
Employer contributions (reimbursements)		46
Plan participants' contributions	16	18
Plan assets at measurement date	220	195	225
Funded status of plan	(503)	(533)
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	174	189
Service cost	1	1	1
Interest cost	7	7	8
Plan participants' contributions	3	3
Actuarial loss (gain)	9	(8)
Transfers	0	0
Benefits paid	(19)	(18)
Obligation at measurement date	175	174	189
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	115	133
Employer contributions	11
Actual return on plan assets	20	(5)
Benefits paid	(19)	(18)
Employer contributions (reimbursements)		2
Plan participants' contributions	3	3
Plan assets at measurement date	130	115	133
Funded status of plan	(45)	(59)
Other Post-Retirement Benefit Plans | Progress Energy
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	303	342
Service cost	1	1	0
Interest cost	12	12	13
Plan participants' contributions	6	6
Actuarial loss (gain)	13	(23)
Transfers	0	0
Benefits paid	(32)	(35)
Obligation at measurement date	303	303	342
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	0	0
Employer contributions	26
Actual return on plan assets	(1)	0
Benefits paid	(32)	(35)
Employer contributions (reimbursements)		29
Plan participants' contributions	6	6
Plan assets at measurement date	(1)	0	0
Funded status of plan	(304)	(303)
Other Post-Retirement Benefit Plans | Duke Energy Progress
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	166	184
Service cost	0	0	0
Interest cost	7	6	7
Plan participants' contributions	3	4
Actuarial loss (gain)	9	(9)
Transfers	0	0
Benefits paid	(17)	(19)
Obligation at measurement date	168	166	184
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	0	0
Employer contributions	13
Actual return on plan assets	0	0
Benefits paid	(17)	(19)
Employer contributions (reimbursements)		15
Plan participants' contributions	3	4
Plan assets at measurement date	(1)	0	0
Funded status of plan	(169)	(166)
Other Post-Retirement Benefit Plans | Duke Energy Florida
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	137	156
Service cost	1	1	0
Interest cost	5	6	6
Plan participants' contributions	2	3
Actuarial loss (gain)	5	(13)
Transfers	0	0
Benefits paid	(15)	(16)
Obligation at measurement date	135	137	156
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	0	0
Employer contributions	13
Actual return on plan assets	0	0
Benefits paid	(15)	(16)
Employer contributions (reimbursements)		13
Plan participants' contributions	2	3
Plan assets at measurement date	0	0	0
Funded status of plan	(135)	(137)
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	29	30
Service cost	0	1	0
Interest cost	1	1	1
Plan participants' contributions	1	1
Actuarial loss (gain)	1	(2)
Transfers	0	0
Benefits paid	(3)	(2)
Obligation at measurement date	29	29	30
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	8	7
Employer contributions	2
Actual return on plan assets	1	0
Benefits paid	(3)	(2)
Employer contributions (reimbursements)		2
Plan participants' contributions	1	1
Plan assets at measurement date	9	8	7
Funded status of plan	(20)	(21)
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	67	78
Service cost	1	1	0
Interest cost	3	3	3
Plan participants' contributions	2	2
Actuarial loss (gain)	2	(5)
Transfers	0	0
Benefits paid	(11)	(12)
Obligation at measurement date	64	67	78
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	5	11
Employer contributions	9
Actual return on plan assets	0	0
Benefits paid	(11)	(12)
Employer contributions (reimbursements)		4
Plan participants' contributions	2	2
Plan assets at measurement date	5	5	11
Funded status of plan	(59)	(62)
Other Post-Retirement Benefit Plans | Piedmont
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	30	32
Service cost	0	1	1
Interest cost	1	1	1
Plan participants' contributions	0	0
Actuarial loss (gain)	0	(1)
Transfers	0	(1)
Benefits paid	(1)	(2)
Obligation at measurement date	30	30	32
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	29	31
Employer contributions	0
Actual return on plan assets	6	(1)
Benefits paid	(1)	(2)
Employer contributions (reimbursements)		1
Plan participants' contributions	0	0
Plan assets at measurement date	34	29	$ 31
Funded status of plan	$ 4	$ (1)

Employee Benefit Plans (Amoun_2

Employee Benefit Plans (Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	$ 934	$ 988
Regulatory assets	15,018	15,622
Regulatory liabilities	16,048	15,432
Duke Energy Carolinas
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	84	99
Regulatory assets	3,910	3,977
Regulatory liabilities	6,678	6,198
Progress Energy
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	488	521
Regulatory assets	7,292	7,701
Regulatory liabilities	5,555	5,329
Duke Energy Progress
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	238	237
Regulatory assets	4,678	4,814
Regulatory liabilities	4,468	4,133
Duke Energy Florida
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	218	254
Regulatory assets	2,613	2,888
Regulatory liabilities	1,087	1,196
Duke Energy Ohio
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	100	79
Regulatory assets	598	564
Regulatory liabilities	827	897
Duke Energy Indiana
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	148	115
Regulatory assets	1,172	1,157
Regulatory liabilities	1,740	1,747
Piedmont
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	3	4
Regulatory assets	363	357
Regulatory liabilities	1,212	1,218
Pension Plan | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	621	433
Noncurrent pension liability	32	69
Net amount recognized	589	364
Regulatory assets	1,972	2,184
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(23)	(43)
Prior year service cost (credit) arising during the year	(3)	(4)
Net actuarial loss (gain)	111	126
Net amount recognized in accumulated other comprehensive income (loss)	85	79
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	135	97
Unrecognized prior service (credit) cost	(32)	(32)
Pension Plan | Duke Energy Carolinas | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	340	214
Noncurrent pension liability	0	0
Net amount recognized	340	214
Regulatory assets	420	576
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	29	22
Unrecognized prior service (credit) cost	(8)	(8)
Pension Plan | Progress Energy | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	322	242
Noncurrent pension liability	32	69
Net amount recognized	290	173
Regulatory assets	717	796
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(1)	(2)
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	3	5
Net amount recognized in accumulated other comprehensive income (loss)	2	3
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	43	37
Unrecognized prior service (credit) cost	(3)	(3)
Pension Plan | Duke Energy Progress | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	194	143
Noncurrent pension liability	0	0
Net amount recognized	194	143
Regulatory assets	313	372
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	19	13
Unrecognized prior service (credit) cost	(2)	(2)
Pension Plan | Duke Energy Florida | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	123	96
Noncurrent pension liability	32	69
Net amount recognized	91	27
Regulatory assets	404	424
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(1)	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	3	0
Net amount recognized in accumulated other comprehensive income (loss)	2	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	24	24
Unrecognized prior service (credit) cost	(1)	(1)
Pension Plan | Duke Energy Ohio | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	38	24
Noncurrent pension liability	76	54
Net amount recognized	(38)	(30)
Regulatory assets	112	100
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	7	3
Unrecognized prior service (credit) cost	(1)	0
Pension Plan | Duke Energy Indiana | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	57	39
Noncurrent pension liability	83	46
Net amount recognized	(26)	(7)
Regulatory assets	204	182
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	10	5
Unrecognized prior service (credit) cost	(2)	(2)
Pension Plan | Piedmont | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	43	41
Noncurrent pension liability	0	0
Net amount recognized	43	41
Regulatory assets	81	81
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	9	7
Unrecognized prior service (credit) cost	(9)	(9)
Other Post-Retirement Benefit Plans
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	9	8
Noncurrent pension liability	494	525
Total accrued pension liability	503	533
Regulatory assets	135	262
Regulatory liabilities	149	301
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	3	3
Prior year service cost (credit) arising during the year	(2)	(2)
Net actuarial loss (gain)	(13)	(9)
Net amount recognized in accumulated other comprehensive income (loss)	(12)	(8)
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	5	4
Unrecognized prior service (credit) cost	(14)	(19)
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0	0
Noncurrent pension liability	45	59
Total accrued pension liability	45	59
Regulatory assets	0	0
Regulatory liabilities	39	38
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	3	2
Unrecognized prior service (credit) cost	(4)	(5)
Other Post-Retirement Benefit Plans | Progress Energy
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	5	5
Noncurrent pension liability	299	298
Total accrued pension liability	304	303
Regulatory assets	135	262
Regulatory liabilities	0	149
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	1	1
Unrecognized prior service (credit) cost	(3)	(7)
Other Post-Retirement Benefit Plans | Duke Energy Progress
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	3	3
Noncurrent pension liability	166	163
Total accrued pension liability	169	166
Regulatory assets	82	164
Regulatory liabilities	0	93
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	0	0
Unrecognized prior service (credit) cost	(1)	(1)
Other Post-Retirement Benefit Plans | Duke Energy Florida
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	2
Noncurrent pension liability	133	135
Total accrued pension liability	135	137
Regulatory assets	53	98
Regulatory liabilities	0	56
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	1	0
Unrecognized prior service (credit) cost	(2)	(6)
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	1	2
Noncurrent pension liability	19	19
Total accrued pension liability	20	21
Regulatory assets	0	0
Regulatory liabilities	17	18
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	0	0
Unrecognized prior service (credit) cost	(1)	(1)
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0	0
Noncurrent pension liability	59	62
Total accrued pension liability	59	62
Regulatory assets	36	41
Regulatory liabilities	63	67
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	0	0
Unrecognized prior service (credit) cost	(1)	(1)
Other Post-Retirement Benefit Plans | Piedmont
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0	0
Noncurrent pension liability	(4)	1
Total accrued pension liability	(4)	1
Regulatory assets	0	0
Regulatory liabilities	3	0
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	0	0
Prior year service cost (credit) arising during the year	0	0
Net actuarial loss (gain)	0	0
Net amount recognized in accumulated other comprehensive income (loss)	0	0
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	0	0
Unrecognized prior service (credit) cost	$ (2)	$ (2)

Employee Benefit Plans (Informa

Employee Benefit Plans (Information For Plans with Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - Pension Plan - Qualified Plan - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation		$ 679
Accumulated benefit obligation		651
Fair value of plan assets		610
Progress Energy
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation		679
Accumulated benefit obligation		651
Fair value of plan assets		610
Duke Energy Florida
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation		679
Accumulated benefit obligation		651
Fair value of plan assets		610
Duke Energy Ohio
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 155	123
Accumulated benefit obligation	146	115
Fair value of plan assets	79	69
Duke Energy Indiana
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	260	203
Accumulated benefit obligation	252	199
Fair value of plan assets	$ 177	$ 159

Employee Benefit Plans (Assumpt

Employee Benefit Plans (Assumptions Used For Pension Benefits Accounting) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan | Qualified Plan
Benefit Obligations [Abstract]
Discount rate	3.30%	4.30%	3.60%
Net Periodic Benefit Cost [Abstract]
Discount rate	4.30%	3.60%	4.10%
Expected long-term rate of return on plan assets	6.85%	6.50%	6.75%
Pension Plan | Minimum | Qualified Plan
Benefit Obligations [Abstract]
Salary increase	3.50%	3.50%	3.50%
Net Periodic Benefit Cost [Abstract]
Salary increase	3.50%	3.50%	4.00%
Expected long-term rate of return on plan assets			6.50%
Pension Plan | Maximum | Qualified Plan
Benefit Obligations [Abstract]
Salary increase	4.00%	4.00%	4.00%
Net Periodic Benefit Cost [Abstract]
Salary increase	4.00%	4.00%	4.50%
Other Post-Retirement Benefit Plans
Benefit Obligations [Abstract]
Discount rate	3.30%	4.30%	3.60%
Net Periodic Benefit Cost [Abstract]
Discount rate	4.30%	3.60%	4.10%
Expected long-term rate of return on plan assets	6.85%	6.50%	6.50%
Assumed tax rate	23.00%	35.00%	35.00%

Employee Benefit Plans (Assumed

Employee Benefit Plans (Assumed Health Care Cost Trend Rates) (Details)	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	6.00%	6.50%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	4.75%	4.75%

Employee Benefit Plans (Sensiti

Employee Benefit Plans (Sensitivity to Changes in Assumed Health Care Cost Trend Rates) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	$ 1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	22
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(20)
Duke Energy Carolinas
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	0
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	5
Effect on total service and interest costs - 1 Percentage Point Decrease	0
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(5)
Progress Energy
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	9
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(8)
Duke Energy Progress
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	5
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(4)
Duke Energy Florida
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	0
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	4
Effect on total service and interest costs - 1 Percentage Point Decrease	0
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(4)
Duke Energy Ohio
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	0
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	1
Effect on total service and interest costs - 1 Percentage Point Decrease	0
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(1)
Duke Energy Indiana
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	0
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	2
Effect on total service and interest costs - 1 Percentage Point Decrease	0
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(2)
Piedmont
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	0
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	1
Effect on total service and interest costs - 1 Percentage Point Decrease	0
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	$ (1)

Employee Benefit Plans (Expecte

Employee Benefit Plans (Expected Benefit Payments) (Details) $ in Millions	Dec. 31, 2019USD ($)
Pension Plan | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	$ 643
2021	653
2022	649
2023	649
2024	638
2025-2029	2,851
Pension Plan | Duke Energy Carolinas | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	167
2021	171
2022	177
2023	174
2024	168
2025-2029	714
Pension Plan | Progress Energy | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	169
2021	178
2022	176
2023	182
2024	184
2025-2029	871
Pension Plan | Duke Energy Progress | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	89
2021	95
2022	92
2023	95
2024	96
2025-2029	419
Pension Plan | Duke Energy Florida | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	79
2021	82
2022	84
2023	86
2024	87
2025-2029	448
Pension Plan | Duke Energy Ohio | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	37
2021	37
2022	37
2023	36
2024	35
2025-2029	156
Pension Plan | Duke Energy Indiana | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	50
2021	50
2022	49
2023	48
2024	48
2025-2029	220
Pension Plan | Piedmont | Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	28
2021	24
2022	22
2023	21
2024	20
2025-2029	87
Other Post-Retirement Benefit Plans
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	76
2021	70
2022	66
2023	63
2024	59
2025-2029	246
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	18
2021	17
2022	16
2023	15
2024	15
2025-2029	60
Other Post-Retirement Benefit Plans | Progress Energy
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	29
2021	28
2022	27
2023	25
2024	24
2025-2029	101
Other Post-Retirement Benefit Plans | Duke Energy Progress
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	16
2021	15
2022	14
2023	14
2024	13
2025-2029	55
Other Post-Retirement Benefit Plans | Duke Energy Florida
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	13
2021	13
2022	12
2023	12
2024	11
2025-2029	46
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	4
2021	3
2022	3
2023	3
2024	3
2025-2029	11
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	8
2021	7
2022	7
2023	6
2024	6
2025-2029	23
Other Post-Retirement Benefit Plans | Piedmont
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	2
2021	2
2022	2
2023	2
2024	2
2025-2029	$ 11

Employee Benefit Plans (Target

Employee Benefit Plans (Target and Actual Asset Allocations) (Details)	Dec. 31, 2019	Dec. 31, 2018
Master Trust
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	100.00%	100.00%
Target allocation	100.00%
Master Trust | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	0.00%	11.00%
Target allocation	0.00%
Master Trust | Global equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	27.00%	18.00%
Target allocation	28.00%
Master Trust | Global private equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	1.00%	2.00%
Target allocation	1.00%
Master Trust | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	57.00%	63.00%
Target allocation	58.00%
Master Trust | Return seeking debt securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	5.00%	0.00%
Target allocation	4.00%
Master Trust | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	3.00%	2.00%
Target allocation	3.00%
Master Trust | Real estate and cash
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	7.00%	2.00%
Target allocation	6.00%
Master Trust | Other global securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	0.00%	2.00%
Target allocation	0.00%
OPEB
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	100.00%	100.00%
Target allocation	100.00%
OPEB | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	35.00%	43.00%
Target allocation	33.00%
OPEB | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	9.00%	8.00%
Target allocation	7.00%
OPEB | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	37.00%	40.00%
Target allocation	45.00%
OPEB | Real estate
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	2.00%	2.00%
Target allocation	2.00%
OPEB | Cash
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	17.00%	7.00%
Target allocation	13.00%

Employee Benefit Plans (Fair Va

Employee Benefit Plans (Fair Value Measurements of Plan Assets - Master Retirement Trust) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ 11	$ 27	$ 28
Master Trust
Defined Benefit Plan Disclosure [Line Items]
Total assets	9,025	8,324
Master Trust | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	3,199	2,052
Master Trust | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	5,487	5,133
Master Trust | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	11	27
Master Trust | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	328	1,112
Master Trust | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	2,730	2,373
Master Trust | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	2,712	1,751
Master Trust | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Equity securities | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	18	622
Master Trust | Corporate debt securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	3,999	4,054
Master Trust | Corporate debt securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Corporate debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	3,999	4,054
Master Trust | Corporate debt securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Corporate debt securities | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Short-term investment funds
Defined Benefit Plan Disclosure [Line Items]
Total assets	545	363
Master Trust | Short-term investment funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	455	279
Master Trust | Short-term investment funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	90	84
Master Trust | Short-term investment funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Short-term investment funds | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Partnership interests
Defined Benefit Plan Disclosure [Line Items]
Total assets	104	120
Master Trust | Partnership interests | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Partnership interests | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Partnership interests | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Partnership interests | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	104	120
Master Trust | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total assets	206	226
Master Trust | Hedge funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Hedge funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Hedge funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Hedge funds | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	206	226
Master Trust | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	144
Master Trust | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Real estate | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	144
Master Trust | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Total assets	1,231	961
Master Trust | U.S. government bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | U.S. government bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	1,231	961
Master Trust | U.S. government bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | U.S. government bonds | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Guaranteed investment contracts
Defined Benefit Plan Disclosure [Line Items]
Total assets	11	27
Master Trust | Guaranteed investment contracts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Guaranteed investment contracts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Guaranteed investment contracts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	11	27
Master Trust | Guaranteed investment contracts | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Governments bonds – foreign
Defined Benefit Plan Disclosure [Line Items]
Total assets	78	30
Master Trust | Governments bonds – foreign | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Governments bonds – foreign | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	78	30
Master Trust | Governments bonds – foreign | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Governments bonds – foreign | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Cash
Defined Benefit Plan Disclosure [Line Items]
Total assets	75	28
Master Trust | Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	75	28
Master Trust | Cash | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Cash | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Cash | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Net pending transactions and other investments
Defined Benefit Plan Disclosure [Line Items]
Total assets	46	(2)
Master Trust | Net pending transactions and other investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	(43)	(6)
Master Trust | Net pending transactions and other investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	89	4
Master Trust | Net pending transactions and other investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
Master Trust | Net pending transactions and other investments | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	0	0
OPEB
Defined Benefit Plan Disclosure [Line Items]
Total assets	50	49
OPEB | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	50	49
OPEB | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	22	25
OPEB | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	22	25
OPEB | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total assets	1	1
OPEB | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	1	1
OPEB | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total assets	9	3
OPEB | Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	9	3
OPEB | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	18	20
OPEB | Debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ 18	$ 20
Duke Energy Carolinas | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	26.00%	27.00%
Progress Energy | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	31.00%	31.00%
Duke Energy Progress | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	15.00%	15.00%
Duke Energy Florida | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	17.00%	16.00%
Duke Energy Ohio | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	5.00%	5.00%
Duke Energy Indiana | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	7.00%	7.00%
Piedmont | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	4.00%	4.00%

Employee Benefit Plans (Reconci

Employee Benefit Plans (Reconciliation of Assets Measured at Fair Value on a Recurring Basis) (Details) - Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Plan assets at prior measurement date	$ 27	$ 28
Sales	(18)	(1)
Total gains (losses) and other, net	2	0
Transfer of Level 3 assets to other classifications	0	0
Plan assets at measurement date	$ 11	$ 27

Employee Benefit Plans (Employe

Employee Benefit Plans (Employee Savings Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Savings Plans [Abstract]
Matching contribution percentage	100.00%
Eligible pay percentage	6.00%
Additional contribution percentage for employees not participating in defined pension plans	4.00%
Employer contributions	$ 214	$ 213	$ 179
Duke Energy Carolinas
Employee Savings Plans [Abstract]
Employer contributions	66	68	61
Progress Energy
Employee Savings Plans [Abstract]
Employer contributions	58	58	53
Duke Energy Progress
Employee Savings Plans [Abstract]
Employer contributions	38	40	37
Duke Energy Florida
Employee Savings Plans [Abstract]
Employer contributions	20	19	16
Duke Energy Ohio
Employee Savings Plans [Abstract]
Employer contributions	5	4	3
Duke Energy Indiana
Employee Savings Plans [Abstract]
Employer contributions	11	10	9
Piedmont
Employee Savings Plans [Abstract]
Employer contributions	$ 13	$ 12	$ 7
Minimum | Piedmont
Employee Savings Plans [Abstract]
Additional contribution percentage for employees not participating in defined pension plans	3.00%
Maximum | Piedmont
Employee Savings Plans [Abstract]
Additional contribution percentage for employees not participating in defined pension plans	5.00%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Line Items]
Refund of AMT credit carryforwards		$ 573
Reclassification of AMT credits from noncurrent deferred tax liabilities to a current federal income tax receivable		286
Decrease in unrecognized tax benefits is reasonably possible		3
AMT credit carryforwards
Income Tax Disclosure [Line Items]
Refund of AMT credit carryforwards		$ 573
Analysis of existing regulatory liability
Income Tax Disclosure [Line Items]
Measurement period adjustments			$ (23)
Bonus depreciation
Income Tax Disclosure [Line Items]
Measurement period adjustments			(10)
Nondeductible long-term incentives
Income Tax Disclosure [Line Items]
Measurement period adjustments			(7)
Refundable AMT credits
Income Tax Disclosure [Line Items]
Measurement period adjustments	$ (76)
Regulatory liability
Income Tax Disclosure [Line Items]
Measurement period adjustments			(83)
Reclassified AMT credit carryforwards
Income Tax Disclosure [Line Items]
Measurement period adjustments			$ (573)

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	$ (299)	$ (647)	$ (247)
Current state taxes	10	(11)	4
Current foreign taxes	2	3	3
Total current income taxes	(287)	(655)	(240)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	855	1,064	1,344
Deferred state taxes	(38)	49	102
Total deferred income taxes	817	1,113	1,446
ITC amortization	(11)	(10)	(10)
Income tax expense (benefit) from continuing operations	519	448	1,196
Tax expense (benefit) from discontinued operations	(2)	(26)	(6)
Total income tax expense included in Consolidated Statements of Operations	517	422	1,190
Net operating loss carry forward	(775)	(18)	428
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Domestic	4,053	3,018	4,207
Foreign	44	55	59
Total income from continuing operations before income taxes	4,097	3,073	4,266
Equity in losses of unconsolidated affiliates	(162)	(83)	(119)
Duke Energy Carolinas
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	164	(8)	221
Current state taxes	13	6	20
Current foreign taxes		0	0
Total current income taxes	177	(2)	241
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	175	299	381
Deferred state taxes	(37)	11	35
Total deferred income taxes	138	310	416
ITC amortization	(4)	(5)	(5)
Income tax expense (benefit) from continuing operations	311	303	652
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	311	303	652
Net operating loss carry forward	8	22	10
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	1,714	1,374	1,866
Progress Energy
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(173)	(135)	(436)
Current state taxes	(7)	(5)	(5)
Current foreign taxes		0	0
Total current income taxes	(180)	(140)	(441)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	422	341	664
Deferred state taxes	17	20	44
Total deferred income taxes	439	361	708
ITC amortization	(6)	(3)	(3)
Income tax expense (benefit) from continuing operations	253	218	264
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	253	218	264
Net operating loss carry forward	(243)	(293)	(74)
Duke Energy Progress
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(36)	(71)	(95)
Current state taxes	(3)	(5)	2
Current foreign taxes		0	0
Total current income taxes	(39)	(76)	(93)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	220	256	378
Deferred state taxes	(18)	(17)	10
Total deferred income taxes	202	239	388
ITC amortization	(6)	(3)	(3)
Income tax expense (benefit) from continuing operations	157	160	292
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	157	160	292
Net operating loss carry forward	35	59	1
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	962	827	1,007
Duke Energy Florida
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(43)	(49)	(188)
Current state taxes	18	(10)	(11)
Current foreign taxes		0	0
Total current income taxes	(25)	(59)	(199)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	153	115	194
Deferred state taxes	27	45	51
Total deferred income taxes	180	160	245
ITC amortization		0	0
Income tax expense (benefit) from continuing operations	155	101	46
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	155	101	46
Net operating loss carry forward	(152)	(219)	(36)
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	847	655	758
Duke Energy Ohio
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(41)	20	(37)
Current state taxes	(1)	(1)	2
Current foreign taxes		0	0
Total current income taxes	(42)	19	(35)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	77	21	99
Deferred state taxes	5	3	(4)
Total deferred income taxes	82	24	95
ITC amortization		0	(1)
Income tax expense (benefit) from continuing operations	40	43	59
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	40	43	59
Net operating loss carry forward	(25)	(17)	(17)
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	279	219	252
Duke Energy Indiana
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(23)	29	128
Current state taxes	1	3	21
Current foreign taxes		0	0
Total current income taxes	(22)	32	149
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	128	74	138
Deferred state taxes	28	22	14
Total deferred income taxes	156	96	152
ITC amortization		0	0
Income tax expense (benefit) from continuing operations	134	128	301
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	134	128	301
Net operating loss carry forward	(60)	(21)	(42)
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	570	521	655
Piedmont
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(92)	67	(90)
Current state taxes	(1)	1	(3)
Current foreign taxes		0	0
Total current income taxes	(93)	68	(93)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	133	(36)	147
Deferred state taxes	3	5	8
Total deferred income taxes	136	(31)	155
ITC amortization		0	0
Income tax expense (benefit) from continuing operations	43	37	62
Tax expense (benefit) from discontinued operations		0	0
Total income tax expense included in Consolidated Statements of Operations	43	37	62
Net operating loss carry forward	(90)	(39)	(79)
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	245	166	201
Equity in losses of unconsolidated affiliates	$ (8)	$ (7)	6
Tax Act
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Equity in losses of unconsolidated affiliates			$ 16

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 860	$ 645	$ 1,493
State income tax, net of federal income tax effect	(22)	30	69
Amortization of excess deferred income tax	(121)	(61)
AFUDC equity income	(52)	(42)	(81)
AFUDC equity depreciation	34	31
Renewable energy PTCs	(120)	(129)	(132)
Other tax credits	(23)	(28)
Tax Act		20	(112)
Tax true up	(64)		(52)
Other items, net	27	(18)	11
Income tax expense (benefit) from continuing operations	$ 519	$ 448	$ 1,196
Effective tax rate	12.70%	14.60%	28.00%
Duke Energy Carolinas
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 360	$ 288	$ 653
State income tax, net of federal income tax effect	(19)	14	36
Amortization of excess deferred income tax	(29)
AFUDC equity income	(9)	(15)	(37)
AFUDC equity depreciation	19	18
Other tax credits	(11)	(7)
Tax Act		1	15
Tax true up	(9)		(24)
Other items, net	9	4	9
Income tax expense (benefit) from continuing operations	$ 311	$ 303	$ 652
Effective tax rate	18.10%	22.10%	34.90%
Progress Energy
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 332	$ 263	$ 536
State income tax, net of federal income tax effect	8	13	25
Amortization of excess deferred income tax	(64)	(55)
AFUDC equity income	(14)	(22)	(32)
AFUDC equity depreciation	10	9
Other tax credits	(9)	(13)
Tax Act		25	(246)
Tax true up	(8)		(19)
Other items, net	(2)	(2)
Income tax expense (benefit) from continuing operations	$ 253	$ 218	$ 264
Effective tax rate	16.00%	17.40%	17.20%
Duke Energy Progress
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 202	$ 174	$ 353
State income tax, net of federal income tax effect	(17)	(17)	8
Amortization of excess deferred income tax	(10)	(1)
AFUDC equity income	(13)	(12)	(17)
AFUDC equity depreciation	5	5
Other tax credits	(7)	(5)
Tax Act		19	(40)
Tax true up	(3)		(13)
Other items, net		(3)	1
Income tax expense (benefit) from continuing operations	$ 157	$ 160	$ 292
Effective tax rate	16.30%	19.30%	29.00%
Duke Energy Florida
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 178	$ 137	$ 265
State income tax, net of federal income tax effect	35	28	26
Amortization of excess deferred income tax	(54)	(54)
AFUDC equity income	(1)	(10)	(16)
AFUDC equity depreciation	5	4
Other tax credits	(2)	(8)
Tax Act			(226)
Tax true up	(5)		(7)
Other items, net	(1)	4	4
Income tax expense (benefit) from continuing operations	$ 155	$ 101	$ 46
Effective tax rate	18.30%	15.40%	6.10%
Duke Energy Ohio
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 59	$ 46	$ 88
State income tax, net of federal income tax effect	3	2	(1)
Amortization of excess deferred income tax	(12)	(3)
AFUDC equity income	(3)	(2)	(4)
AFUDC equity depreciation	1	1
Other tax credits	(1)	(1)
Tax Act		2	(23)
Tax true up	(7)		(5)
Other items, net	0	(2)	4
Income tax expense (benefit) from continuing operations	$ 40	$ 43	$ 59
Effective tax rate	14.30%	19.60%	23.40%
Duke Energy Indiana
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 120	$ 109	$ 229
State income tax, net of federal income tax effect	22	20	23
Amortization of excess deferred income tax	(6)	(2)
AFUDC equity income	(3)	(2)	(8)
AFUDC equity depreciation	4	4
Other tax credits	(1)	(1)
Tax Act			55
Tax true up	(1)		(6)
Other items, net	(1)		8
Income tax expense (benefit) from continuing operations	$ 134	$ 128	$ 301
Effective tax rate	23.50%	24.60%	46.00%
Piedmont
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate	$ 51	$ 35	$ 70
State income tax, net of federal income tax effect	2	4	3
Amortization of excess deferred income tax	(10)
Other tax credits	(1)	(3)
Tax Act			(12)
Other items, net	1	1	1
Income tax expense (benefit) from continuing operations	$ 43	$ 37	$ 62
Effective tax rate	17.60%	22.30%	30.80%

Income Taxes (Deferred Income T

Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	$ 125	$ 164
Capital lease obligations	462	60
Pension, postretirement and other employee benefits	303	347
Progress Energy merger purchase accounting adjustments	389	483
Tax credits and NOL carryforwards	3,925	4,580
Other	97	25
Valuation allowance	(587)	(484)
Total deferred income tax assets	4,714	5,175
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(1,664)	(1,317)
Accelerated depreciation rates	(10,813)	(10,124)
Regulatory assets and deferred debits, net	(1,115)	(1,540)
Total deferred income tax liabilities	(13,592)	(12,981)
Net deferred income tax liabilities	(8,878)	(7,806)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	3,925	4,580
Valuation allowance	(587)	(484)
General Business Credits
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	1,821
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	1,821
AMT credits
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	286
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	286
NOL Carryforwards | Federal
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	169
Valuation allowance	(4)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	169
Valuation allowance	(4)
NOL Carryforwards | State
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	303
Valuation allowance	(97)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	303
Valuation allowance	(97)
NOL Carryforwards | Foreign
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	12
Valuation allowance	(12)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	12
Valuation allowance	(12)
Capital loss carryforwards | Federal
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	87
Valuation allowance	(87)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	87
Valuation allowance	(87)
Foreign Tax Credit
Deferred Tax Assets, Gross [Abstract]
Valuation allowance	(387)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Valuation allowance	(387)
Foreign Tax Credit | Foreign
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	1,237
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	1,237
Charitable contribution carryforwards
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	10
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	10
Duke Energy Carolinas
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	24	64
Capital lease obligations	72	26
Pension, postretirement and other employee benefits	(5)	24
Tax credits and NOL carryforwards	262	257
Other	5	6
Total deferred income tax assets	358	377
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(981)	(795)
Accelerated depreciation rates	(3,254)	(3,207)
Regulatory assets and deferred debits, net	(44)	(64)
Total deferred income tax liabilities	(4,279)	(4,066)
Net deferred income tax liabilities	(3,921)	(3,689)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	262	257
Progress Energy
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	25	35
Capital lease obligations	193
Pension, postretirement and other employee benefits	88	110
Tax credits and NOL carryforwards	486	693
Other	8	5
Total deferred income tax assets	800	843
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(577)	(430)
Accelerated depreciation rates	(3,798)	(3,369)
Regulatory assets and deferred debits, net	(887)	(985)
Total deferred income tax liabilities	(5,262)	(4,784)
Net deferred income tax liabilities	(4,462)	(3,941)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	486	693
Duke Energy Progress
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	49	53
Capital lease obligations	92
Pension, postretirement and other employee benefits	38	47
Tax credits and NOL carryforwards	176	215
Other	3	5
Total deferred income tax assets	358	320
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(390)	(272)
Accelerated depreciation rates	(1,918)	(1,735)
Regulatory assets and deferred debits, net	(438)	(432)
Total deferred income tax liabilities	(2,746)	(2,439)
Net deferred income tax liabilities	(2,388)	(2,119)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	176	215
Duke Energy Florida
Deferred Tax Assets, Gross [Abstract]
Capital lease obligations	102
Pension, postretirement and other employee benefits	44	58
Tax credits and NOL carryforwards	253	363
Other	2
Total deferred income tax assets	401	421
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(190)	(163)
Accelerated depreciation rates	(1,913)	(1,670)
Regulatory assets and deferred debits, net	(477)	(574)
Total deferred income tax liabilities	(2,580)	(2,407)
Net deferred income tax liabilities	(2,179)	(1,986)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	253	363
Duke Energy Ohio
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	14	17
Capital lease obligations	5
Pension, postretirement and other employee benefits	17	16
Tax credits and NOL carryforwards	16	42
Regulatory liabilities and deferred credits	36	56
Investments and other assets	10	18
Other	8	1
Total deferred income tax assets	106	150
Deferred Tax Liabilities, Gross [Abstract]
Accelerated depreciation rates	(1,028)	(967)
Total deferred income tax liabilities	(1,028)	(967)
Net deferred income tax liabilities	(922)	(817)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	16	42
Duke Energy Indiana
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	5	6
Capital lease obligations	17	2
Pension, postretirement and other employee benefits	27	24
Tax credits and NOL carryforwards	176	237
Regulatory liabilities and deferred credits	52
Other	1	(1)
Total deferred income tax assets	278	268
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(12)	(5)
Accelerated depreciation rates	(1,416)	(1,081)
Regulatory assets and deferred debits, net		(191)
Total deferred income tax liabilities	(1,428)	(1,277)
Net deferred income tax liabilities	(1,150)	(1,009)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	176	237
Piedmont
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	22	17
Capital lease obligations	6
Pension, postretirement and other employee benefits	(3)	(1)
Tax credits and NOL carryforwards	19	110
Regulatory liabilities and deferred credits	42	48
Investments and other assets	2	16
Other	6
Total deferred income tax assets	94	190
Deferred Tax Liabilities, Gross [Abstract]
Accelerated depreciation rates	(802)	(733)
Other		(8)
Total deferred income tax liabilities	(802)	(741)
Net deferred income tax liabilities	(708)	(551)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	$ 19	$ 110

Income Taxes (Other Disclosures

Income Taxes (Other Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	$ 24	$ 25	$ 17
Gross increases – tax positions in prior periods	105	7	12
Gross decreases – tax positions in prior periods	(3)	(2)	(4)
Decreases due to settlements		(6)
Total changes	102	(1)	8
Unrecognized tax benefits – December 31	126	24	25
Amount that if recognized, would affect the effective tax rate or regulatory liability	122
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	16	2
Interest receivable related to income taxes	1
Interest payable related to income taxes	1	3	5
Duke Energy Carolinas
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	6	5	1
Gross increases – tax positions in prior periods	2	2	4
Gross decreases – tax positions in prior periods		(1)
Total changes	2	1	4
Unrecognized tax benefits – December 31	8	6	5
Amount that if recognized, would affect the effective tax rate or regulatory liability	8
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest expense recognized related to income taxes			2
Interest payable related to income taxes			25
Progress Energy
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	9	5	2
Gross increases – tax positions in prior periods	1	4	3
Gross decreases – tax positions in prior periods	(1)
Total changes		4	3
Unrecognized tax benefits – December 31	9	9	5
Amount that if recognized, would affect the effective tax rate or regulatory liability	9
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	1		1
Interest payable related to income taxes		1	1
Duke Energy Progress
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	6	5	2
Gross increases – tax positions in prior periods	1	1	3
Gross decreases – tax positions in prior periods	(1)
Total changes		1	3
Unrecognized tax benefits – December 31	6	6	5
Amount that if recognized, would affect the effective tax rate or regulatory liability	6
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	1
Interest payable related to income taxes		1	1
Duke Energy Florida
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	3	5	4
Gross increases – tax positions in prior periods		2	1
Gross decreases – tax positions in prior periods		(4)
Total changes		(2)	1
Unrecognized tax benefits – December 31	3	3	5
Amount that if recognized, would affect the effective tax rate or regulatory liability	3
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes			1
Duke Energy Ohio
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	1	1	4
Gross increases – tax positions in prior periods			1
Gross decreases – tax positions in prior periods			(4)
Total changes			(3)
Unrecognized tax benefits – December 31	1	1	1
Amount that if recognized, would affect the effective tax rate or regulatory liability	1
Duke Energy Indiana
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	1	1
Gross increases – tax positions in prior periods			1
Total changes			1
Unrecognized tax benefits – December 31	1	1	1
Amount that if recognized, would affect the effective tax rate or regulatory liability	1
Piedmont
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	4	3
Gross increases – tax positions in prior periods		1	3
Total changes		1	3
Unrecognized tax benefits – December 31	4	$ 4	$ 3
Amount that if recognized, would affect the effective tax rate or regulatory liability	4
Income Tax Examination, Penalties and Interest Expense [Abstract]
Interest payable related to income taxes	$ 1

Other Income and Expenses, Ne_2

Other Income and Expenses, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	$ 31	$ 20	$ 13
AFUDC equity	139	221	237
Post in-service equity returns	29	15	40
Nonoperating income, other	231	143	218
Other income and expense, net	430	399	508
Duke Energy Carolinas
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	1	1	2
AFUDC equity	42	73	106
Post in-service equity returns	20	9	28
Nonoperating income, other	88	70	63
Other income and expense, net	151	153	199
Progress Energy
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	11	18	6
AFUDC equity	66	104	92
Post in-service equity returns	7	5	12
Nonoperating income, other	57	38	99
Other income and expense, net	141	165	209
Duke Energy Progress
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		1	2
AFUDC equity	60	57	47
Post in-service equity returns	7	5	12
Nonoperating income, other	33	24	54
Other income and expense, net	100	87	115
Duke Energy Florida
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	11	18	5
AFUDC equity	6	47	45
Nonoperating income, other	31	21	46
Other income and expense, net	48	86	96
Duke Energy Ohio
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	10	7	6
AFUDC equity	13	11	11
Post in-service equity returns	1	1
Nonoperating income, other		4	6
Other income and expense, net	24	23	23
Duke Energy Indiana
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	10	9	8
AFUDC equity	18	32	28
Post in-service equity returns	0
Nonoperating income, other	13	4	11
Other income and expense, net	41	45	47
Piedmont
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	1	1
Nonoperating income, other	19	13	(11)
Other income and expense, net	$ 20	$ 14	$ (11)

Quarterly Financial Data (Una_3

Quarterly Financial Data (Unaudited) (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	$ 6,103	$ 6,940	$ 5,873	$ 6,163	$ 6,115	$ 6,628	$ 5,643	$ 6,135	$ 25,079	$ 24,521	$ 23,565
Operating income (loss)	1,109	1,929	1,298	1,373	871	1,579	979	1,256	5,709	4,685	5,625
Income (loss) from continuing operations	614	1,323	748	893	434	1,062	507	622	3,578	2,625	3,070
(Loss) Income from discontinued operations, net of tax	(7)				20	4	(5)	0	(7)	19	(6)
Net income (loss)	607	1,323	748	893	454	1,066	502	622	3,571	2,644	3,064
Net income (loss) attributable to parent					$ (464)	$ (1,082)	$ (500)	$ (620)	(3,748)	(2,666)	(3,059)
Net Income (Loss) Available to Common Stockholders, Basic	$ 660	$ 1,327	$ 820	$ 900					$ 3,707	$ 2,666	$ 3,059
Income (loss) from continuing operations attributable to Duke Energy Corporation common shareholders [Abstract]
Basic and diluted (in usd per share)	$ 0.89	$ 1.82	$ 1.12	$ 1.24	$ 0.62	$ 1.51	$ 0.72	$ 0.88	$ 5.07	$ 3.73	$ 4.37
Income (loss) from discontinued operations attributable to Duke Energy Corporation common shareholders [Abstract]
Basic and diluted (in usd per share)	(0.01)		0	0	0.03	0	(0.01)	0	(0.01)	0.03	(0.01)
Net income available to Duke Energy Corporation common stockholders
Basic and diluted (in usd per share)	$ 0.88	$ 1.82	$ 1.12	$ 1.24	$ 0.65	$ 1.51	$ 0.71	$ 0.88	$ 5.06	$ 3.76	$ 4.36
Duke Energy Carolinas
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	$ 1,776	$ 2,162	$ 1,713	$ 1,744	$ 1,775	$ 2,090	$ 1,672	$ 1,763	$ 7,395	$ 7,300	$ 7,302
Operating income (loss)	347	793	451	435	241	713	224	482	2,026	1,660	2,089
Net income (loss) attributable to parent	(219)	(590)	(301)	(293)	(135)	(496)	(117)	(323)	(1,403)	(1,071)	(1,214)
Progress Energy
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	2,644	3,242	2,744	2,572	2,609	3,045	2,498	2,576	11,202	10,728	9,783
Operating income (loss)	447	786	580	488	334	663	484	447	2,301	1,928	2,147
Net income (loss)	229	521	329	248	123	406	267	237	1,327	1,033	1,268
Net income (loss) attributable to parent	(229)	(521)	(328)	(249)	(123)	(404)	(265)	(235)	(1,327)	(1,027)	(1,258)
Duke Energy Progress
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,398	1,688	1,387	1,484	1,366	1,582	1,291	1,460	5,957	5,699	5,129
Operating income (loss)	236	373	259	300	227	330	233	269	1,168	1,059	1,185
Net income (loss) attributable to parent	(155)	(278)	(169)	(203)	(135)	(216)	(139)	(177)	(805)	(667)	(715)
Duke Energy Florida
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,244	1,548	1,353	1,086	1,241	1,462	1,203	1,115	5,231	5,021	4,646
Operating income (loss)	205	413	321	188	107	331	245	173	1,127	856	941
Net income (loss) attributable to parent	(106)	(289)	(201)	(96)	(40)	(243)	(168)	(103)	(692)	(554)	(712)
Duke Energy Ohio
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	487	489	433	531	505	469	459	524	1,940	1,957	1,923
Operating income (loss)	78	108	74	104	93	139	77	(21)	364	288	320
Income (loss) from continuing operations									239	176	193
(Loss) Income from discontinued operations, net of tax									(1)		(1)
Net income (loss) attributable to parent	(48)	(74)	(47)	(69)	(55)	(100)	(46)	25	(238)	(176)	(192)
Duke Energy Indiana
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	715	807	714	768	771	819	738	731	3,004	3,059	3,047
Operating income (loss)	133	235	148	169	133	173	169	168	685	643	786
Net income (loss) attributable to parent	(73)	(156)	(97)	(110)	(76)	(119)	(98)	(100)	(436)	(393)	(354)
Piedmont
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	425	168	209	579	435	172	215	553	1,381	1,375	1,328
Operating income (loss)	139	(13)	6	172	79	(19)	5	161	304	226	297
Net income (loss) attributable to parent	$ (105)	$ 18	$ 7	$ (122)	$ (48)	$ 21	$ 8	$ (110)	$ (202)	$ (129)	$ (139)

Quarterly Financial Data (Una_4

Quarterly Financial Data (Unaudited) (Unusual or Infrequently Occurring Items) (Details) - USD ($) $ in Millions	3 Months Ended						12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charge Reversal	$ (14)	$ 25					$ 11
Total	(14)	25	$ (225)	$ (106)	$ (199)	$ (341)	11	$ (871)
Costs to achieve mergers, integration costs			(31)	(16)	(20)	(17)		(84)
Sale of Retired Plant						107		107
Impairment charges							8	(402)	$ (282)
Severance Costs			(187)				(16)	(187)	(15)
Impairments Charges
Quarterly Financial Information Disclosure [Line Items]
Impairment charges			(60)	(93)		(55)		(208)
Regulatory settlements
Quarterly Financial Information Disclosure [Line Items]
Regulatory and Legislative Impacts					(179)	(86)		(265)
Impacts of the Tax Act
Quarterly Financial Information Disclosure [Line Items]
Tax Act			53	3		(76)		(20)
Duke Energy Carolinas
Quarterly Financial Information Disclosure [Line Items]
Total			(103)	(3)	(181)	(23)		(310)
Costs to achieve mergers, integration costs			(1)	(2)	(2)	(4)		(9)
Impairment charges							(17)	(192)	0
Severance Costs			(102)				(8)	(102)	(2)
Tax Act				(1)				(1)
Duke Energy Carolinas | Regulatory settlements
Quarterly Financial Information Disclosure [Line Items]
Regulatory and Legislative Impacts					(179)	(19)		(198)
Progress Energy
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charge Reversal	11	25					36
Total	11	25	(150)	(6)	(3)	(72)	36	(231)
Costs to achieve mergers, integration costs			(2)	(1)	(3)	(4)		(10)
Impairment charges							24	(87)	(156)
Severance Costs			(69)				(6)	(69)	(2)
Tax Act			(19)	(5)		(1)		(25)
Progress Energy | Impairments Charges
Quarterly Financial Information Disclosure [Line Items]
Impairment charges			(60)					(60)
Progress Energy | Regulatory settlements
Quarterly Financial Information Disclosure [Line Items]
Regulatory and Legislative Impacts						(67)		(67)
Duke Energy Progress
Quarterly Financial Information Disclosure [Line Items]
Total			(68)	(5)	(2)	(69)		(144)
Costs to achieve mergers, integration costs			(1)	(1)	(2)	(2)		(6)
Impairment charges							(12)	(33)	(19)
Severance Costs			(52)				(3)	(52)	(1)
Tax Act			(15)	(4)				(19)
Duke Energy Progress | Regulatory settlements
Quarterly Financial Information Disclosure [Line Items]
Regulatory and Legislative Impacts						(67)		(67)
Duke Energy Florida
Quarterly Financial Information Disclosure [Line Items]
Total	11	25	(76)	(2)	(1)	(2)	36	(81)
Costs to achieve mergers, integration costs			(1)		(1)	(2)		(4)
Impairment charges							36	(54)	(138)
Severance Costs			(17)				(3)	(17)	(1)
Tax Act			2	(2)
Duke Energy Florida | Impairments Charges
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charge Reversal	$ 11	$ 25					36
Impairment charges			(60)					(60)
Duke Energy Ohio
Quarterly Financial Information Disclosure [Line Items]
Total			(14)		(5)	(110)		(129)
Costs to achieve mergers, integration costs			(6)		(5)	(3)		(14)
Sale of Retired Plant						(107)		(107)
Impairment charges									(1)
Severance Costs			(6)					(6)
Tax Act			(2)					(2)
Duke Energy Indiana
Quarterly Financial Information Disclosure [Line Items]
Total			(7)	(2)				(9)
Costs to achieve mergers, integration costs				(2)				(2)
Impairment charges								(30)	(18)
Severance Costs			(7)				(1)	(7)	(1)
Piedmont
Quarterly Financial Information Disclosure [Line Items]
Total			(24)	(11)	(9)	(6)		(50)
Costs to achieve mergers, integration costs			(22)	$ (11)	$ (9)	$ (6)		(48)
Impairment charges									(7)
Severance Costs			$ (2)				$ (1)	$ (2)	$ (9)