Progress Energy (PREX) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Document Transition Report	false
Document Quarterly Report	true
Entity Registrant Name	DUKE ENERGY CORPORATION
Entity Central Index Key	0001326160
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Entity File Number	1-32853
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		729,032,868
Entity Emerging Growth Company	false
Entity Small Business	false
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
Duke Energy Carolinas [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	DUKE ENERGY CAROLINAS, LLC
Entity Central Index Key	0000030371
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-4928
Entity Emerging Growth Company	false
Entity Small Business	false
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
Progress Energy [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	PROGRESS ENERGY, INC.
Entity Central Index Key	0001094093
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-15929
Entity Emerging Growth Company	false
Entity Small Business	false
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
Duke Energy Progress [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	DUKE ENERGY PROGRESS, LLC
Entity Central Index Key	0000017797
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-3382
Entity Emerging Growth Company	false
Entity Small Business	false
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
Duke Energy Florida [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	DUKE ENERGY FLORIDA, LLC
Entity Central Index Key	0000037637
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-3274
Entity Small Business	false
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
Duke Energy Ohio [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	DUKE ENERGY OHIO, INC.
Entity Central Index Key	0000020290
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-1232
Entity Small Business	false
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
Duke Energy Indiana [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	DUKE ENERGY INDIANA, LLC
Entity Central Index Key	0000081020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-3543
Entity Small Business	false
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
Piedmont Natural Gas [Member]
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Registrant Name	PIEDMONT NATURAL GAS COMPANY, INC.
Entity Central Index Key	0000078460
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	1-6196
Entity Small Business	false
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
Common Stock [Member]
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 [Member]
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 [Member]
Document Information [Line Items]
Title of 12(b) Security	5.625% Junior Subordinated Debentures
Trading Symbol	DUKB
Security Exchange Name	NYSE
Depositary Share [Member]
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares
Trading Symbol	DUK PR A
Security Exchange Name	NYSE

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating Revenues
Regulated electric	$ 6,515	$ 6,216	$ 17,223	$ 16,678
Regulated natural gas	223	230	1,231	1,221
Nonregulated electric and other	202	182	522	507
Total operating revenues	6,940	6,628	18,976	18,406
Operating Expenses
Operation, maintenance and other	1,484	1,584	4,337	4,592
Depreciation and amortization	1,186	1,039	3,364	2,979
Property and other taxes	335	323	1,012	954
Impairment charges	(20)	124	(16)	339
Total operating expenses	5,011	5,059	14,376	14,505
Gains (Losses) on Sales of Other Assets and Other, net		10		(87)
Operating Income	1,929	1,579	4,600	3,814
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	50	37	137	49
Other income and expenses, net	104	131	308	327
Total other income and expenses	154	168	445	376
Interest Expense	572	517	1,657	1,550
Income From Continuing Operations Before Income Taxes	1,511	1,230	3,388	2,640
Income Tax Expense From Continuing Operations	188	168	424	449
Income From Continuing Operations	1,323	1,062	2,964	2,191
Income (Loss) From Discontinued Operations, net of tax		4		(1)
Net Income	1,323	1,066	2,964	2,190
Less: Net Loss Attributable to Noncontrolling Interests	(19)	(16)	(110)	(12)
Less: Preferred Dividends	15		27
Net Income Attributable to Duke Energy Corporation	1,327	1,082	3,047	2,202
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	(2)	1	1	3
Net unrealized (losses) gains on cash flow hedges	(16)	(3)	(62)	10
Reclassification into earnings from cash flow hedges	1	6	4	5
Unrealized gains (losses) on available-for-sale securities	2		10	(5)
Other Comprehensive (Loss) Income, net of tax	(15)	4	(47)	13
Comprehensive Income	1,308	1,070	2,917	2,203
Less: Comprehensive Loss Attributable to Noncontrolling Interests	(19)	(16)	(110)	(12)
Less: Preferred Dividends	15		27
Comprehensive Income Attributable to Duke Energy Corporation	$ 1,312	$ 1,086	$ 3,000	$ 2,215
Net income attributable to Duke Energy Corporation common stockholders
Basic (in usd per share)	$ 1.82	$ 1.51	$ 4.18	$ 3.12
Diluted (in usd per share)	1.82	1.51	4.18	3.11
Basic (in usd per share)	1.82	1.51	4.18	3.12
Diluted (in usd per share)	$ 1.82	$ 1.51	$ 4.18	$ 3.11
Weighted average shares outstanding
Weighted Average Number of Shares Outstanding, Basic	729	713	728	705
Weighted Average Number of Shares Outstanding, Diluted	729	714	728	706
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 2,162	$ 2,090	$ 5,619	$ 5,525
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	504	490	1,371	1,370
Operation, maintenance and other	443	514	1,324	1,464
Depreciation and amortization	350	305	1,013	866
Property and other taxes	66	67	221	214
Impairment charges	6	1	11	191
Total operating expenses	1,369	1,377	3,940	4,105
Gains (Losses) on Sales of Other Assets and Other, net				(1)
Operating Income	793	713	1,679	1,419
Other Income and Expenses
Total other income and expenses	34	34	106	108
Interest Expense	119	106	346	323
Income From Continuing Operations Before Income Taxes	708	641	1,439	1,204
Income Tax Expense From Continuing Operations	118	145	255	268
Net Income Attributable to Duke Energy Corporation	590	496	1,184	936
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges				1
Other Comprehensive (Loss) Income, net of tax				1
Comprehensive Income Attributable to Duke Energy Corporation	590	496	1,184	937
Progress Energy [Member]
Operating Revenues
Total operating revenues	3,242	3,045	8,558	8,119
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	1,187	1,148	3,100	3,019
Operation, maintenance and other	640	680	1,813	1,913
Depreciation and amortization	496	419	1,377	1,183
Property and other taxes	159	145	439	399
Impairment charges	(25)	1	(25)	34
Total operating expenses	2,457	2,393	6,704	6,548
Gains (Losses) on Sales of Other Assets and Other, net	1	11		23
Operating Income	786	663	1,854	1,594
Other Income and Expenses
Total other income and expenses	41	51	106	128
Interest Expense	212	214	650	626
Income From Continuing Operations Before Income Taxes	615	500	1,310	1,096
Income Tax Expense From Continuing Operations	94	94	212	186
Net Income	521	406	1,098	910
Less: Net Loss Attributable to Noncontrolling Interests	0	2	0	6
Net Income Attributable to Duke Energy Corporation	521	404	1,098	904
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments			2	2
Net unrealized (losses) gains on cash flow hedges	1	2	4	5
Unrealized gains (losses) on available-for-sale securities	1		2	(1)
Other Comprehensive (Loss) Income, net of tax	2	2	8	6
Comprehensive Income	523	408	1,106	916
Less: Comprehensive Loss Attributable to Noncontrolling Interests		2		6
Comprehensive Income Attributable to Duke Energy Corporation	523	406	1,106	910
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,688	1,582	4,559	4,333
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	577	535	1,571	1,452
Operation, maintenance and other	378	431	1,070	1,187
Depreciation and amortization	314	253	855	723
Property and other taxes	46	40	131	115
Impairment charges				33
Total operating expenses	1,315	1,259	3,627	3,510
Gains (Losses) on Sales of Other Assets and Other, net		7		9
Operating Income	373	330	932	832
Other Income and Expenses
Total other income and expenses	27	24	75	61
Interest Expense	74	82	232	241
Income From Continuing Operations Before Income Taxes	326	272	775	652
Income Tax Expense From Continuing Operations	48	56	125	120
Net Income Attributable to Duke Energy Corporation	278	216	650	532
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation			650	532
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,548	1,462	3,987	3,780
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	610	614	1,529	1,567
Operation, maintenance and other	256	245	730	719
Depreciation and amortization	182	166	522	460
Property and other taxes	113	105	309	284
Impairment charges	(25)	1	(25)	1
Total operating expenses	1,136	1,131	3,065	3,031
Gains (Losses) on Sales of Other Assets and Other, net	1
Operating Income	413	331	922	749
Other Income and Expenses
Total other income and expenses	14	28	39	75
Interest Expense	81	73	246	210
Income From Continuing Operations Before Income Taxes	346	286	715	614
Income Tax Expense From Continuing Operations	57	43	129	100
Net Income Attributable to Duke Energy Corporation	289	243	586	514
Other Comprehensive Income (Loss), net of tax
Unrealized gains (losses) on available-for-sale securities	1		2	(1)
Other Comprehensive (Loss) Income, net of tax	1		2	(1)
Comprehensive Income Attributable to Duke Energy Corporation	290	243	588	513
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	408	373	1,099	1,055
Regulated natural gas	81	84	354	361
Nonregulated electric and other		12		36
Total operating revenues	489	469	1,453	1,452
Operating Expenses
Operation, maintenance and other	123	76	378	337
Depreciation and amortization	69	64	199	196
Property and other taxes	71	73	229	218
Total operating expenses	381	330	1,167	1,151
Gains (Losses) on Sales of Other Assets and Other, net				(106)
Operating Income	108	139	286	195
Other Income and Expenses
Total other income and expenses	4	3	19	17
Interest Expense	27	23	81	68
Income From Continuing Operations Before Income Taxes	85	119	224	144
Income Tax Expense From Continuing Operations	11	19	34	23
Net Income Attributable to Duke Energy Corporation	74	100	190	121
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation			190	121
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	807	819	2,289	2,288
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	234	272	720	730
Operation, maintenance and other	192	198	569	576
Depreciation and amortization	130	130	393	386
Property and other taxes	16	16	55	56
Impairment charges		30		30
Total operating expenses	572	646	1,737	1,778
Operating Income	235	173	552	510
Other Income and Expenses
Total other income and expenses	8	23	35	36
Interest Expense	40	42	111	125
Income From Continuing Operations Before Income Taxes	203	154	476	421
Income Tax Expense From Continuing Operations	47	35	113	104
Net Income Attributable to Duke Energy Corporation	156	119	363	317
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation			363	317
Piedmont Natural Gas [Member]
Operating Revenues
Total operating revenues	168	172	956	940
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	46	54	384	387
Operation, maintenance and other	78	85	241	252
Depreciation and amortization	43	40	127	118
Property and other taxes	14	12	39	36
Total operating expenses	181	191	791	793
Operating Income	(13)	(19)	165	147
Other Income and Expenses
Equity in earnings of unconsolidated affiliates			6	6
Total other income and expenses	7	6	19	15
Interest Expense	22	19	65	60
Income From Continuing Operations Before Income Taxes	(28)	(32)	119	102
Income Tax Expense From Continuing Operations	(10)	(11)	22	21
Net Income Attributable to Duke Energy Corporation	(18)	(21)	97	81
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation			97	81
Electricity, US Regulated [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	114	99	293	284
Electricity, Nonregulated [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		14		43
Electricity [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	1,978	1,931	5,228	5,181
Natural Gas [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	48	58	451	460
Natural Gas [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	$ 4	$ 4	$ 68	$ 73

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net Income	$ 1,323	$ 1,066	$ 2,964	$ 2,190
Other Comprehensive (Loss) Income, net of tax
Pension and OPEB adjustments	(2)	1	1	3
Net unrealized (losses) gains on cash flow hedges	(16)	(3)	(62)	10
Reclassification into earnings from cash flow hedges	1	6	4	5
Unrealized gains (losses) on available-for-sale securities	2		10	(5)
Other Comprehensive (Loss) Income, net of tax	(15)	4	(47)	13
Comprehensive Income	1,308	1,070	2,917	2,203
Less: Comprehensive Loss Attributable to Noncontrolling Interests	(19)	(16)	(110)	(12)
Less: Preferred Dividends	15		27
Comprehensive Income Attributable to Duke Energy Corporation	$ 1,312	$ 1,086	$ 3,000	$ 2,215

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 379	$ 442
Receivables (net of allowance for doubtful accounts)	755	962
Receivables of VIEs (net of allowance for doubtful accounts)	2,322	2,172
Inventory	3,107	3,084
Regulatory assets (includes amounts related to VIEs)	1,723	2,005
Other (includes amounts related to VIEs)	1,333	1,049
Total current assets	9,619	9,714
Property, Plant and Equipment
Cost	143,794	134,458
Accumulated depreciation and amortization	(45,149)	(43,126)
Generation facilities to be retired, net	267	362
Net property, plant and equipment	98,912	91,694
Other Noncurrent Assets
Goodwill	19,303	19,303
Regulatory assets (includes amounts related to VIEs)	13,916	13,617
Nuclear decommissioning trust funds	7,695	6,720
Operating lease right-of-use assets, net	1,703
Investments in equity method unconsolidated affiliates	1,864	1,409
Other (includes amounts related to VIEs)	2,905	2,935
Total other noncurrent assets	47,386	43,984
Total Assets	155,917	145,392
Current Liabilities
Accounts payable	2,946	3,487
Notes payable and commercial paper	2,469	3,410
Taxes accrued	712	577
Interest accrued	559	559
Current maturities of long-term debt (includes amounts related to VIEs)	3,096	3,406
Asset retirement obligations	861	919
Regulatory liabilities	673	598
Other	2,074	2,085
Total current liabilities	13,390	15,041
Long-Term Debt (includes amounts related to VIEs)	54,818	51,123
Other Noncurrent Liabilities
Deferred income taxes	8,776	7,806
Asset retirement obligations	11,740	9,548
Regulatory liabilities	15,202	14,834
Operating lease liabilities	1,456
Accrued pension and other post-retirement benefit costs	900	988
Investment tax credits	579	568
Other (includes amounts related to VIEs)	1,649	1,650
Total other noncurrent liabilities	40,302	35,394
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	40,488	40,795
Retained earnings	4,139	3,113
Accumulated other comprehensive loss	(153)	(92)
Total Duke Energy Corporation stockholders' equity	46,438	43,817
Noncontrolling interests	969	17
Total equity	47,407	43,834
Total Liabilities and Equity	155,917	145,392
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	23	33
Receivables (net of allowance for doubtful accounts)	234	219
Receivables of VIEs (net of allowance for doubtful accounts)	775	699
Receivables from affiliated companies	108	182
Inventory	943	948
Regulatory assets (includes amounts related to VIEs)	573	520
Other (includes amounts related to VIEs)	19	72
Total current assets	2,675	2,673
Property, Plant and Equipment
Cost	47,815	44,741
Accumulated depreciation and amortization	(16,359)	(15,496)
Net property, plant and equipment	31,456	29,245
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	3,587	3,457
Nuclear decommissioning trust funds	4,104	3,558
Operating lease right-of-use assets, net	135
Other (includes amounts related to VIEs)	1,061	1,027
Total other noncurrent assets	8,887	8,042
Total Assets	43,018	39,960
Current Liabilities
Accounts payable	644	988
Accounts payable to affiliated companies	174	230
Notes payable to affiliated companies	49	439
Taxes accrued	262	171
Interest accrued	138	102
Current maturities of long-term debt (includes amounts related to VIEs)	457	6
Asset retirement obligations	214	290
Regulatory liabilities	197	199
Other	545	571
Total current liabilities	2,680	2,996
Long-Term Debt (includes amounts related to VIEs)	11,001	10,633
Long-Term Debt Payable to Affiliated Companies	300	300
Other Noncurrent Liabilities
Deferred income taxes	3,853	3,689
Asset retirement obligations	5,184	3,659
Regulatory liabilities	6,364	5,999
Operating lease liabilities	108
Accrued pension and other post-retirement benefit costs	88	99
Investment tax credits	232	231
Other (includes amounts related to VIEs)	617	671
Total other noncurrent liabilities	16,446	14,348
Equity
Member's equity	12,598	11,689
Accumulated other comprehensive loss	(7)	(6)
Total member's equity	12,591	11,683
Total Liabilities and Equity	43,018	39,960
Progress Energy [Member]
Current Assets
Cash and cash equivalents	82	67
Receivables (net of allowance for doubtful accounts)	181	220
Receivables of VIEs (net of allowance for doubtful accounts)	1,042	909
Receivables from affiliated companies	33	168
Inventory	1,434	1,459
Regulatory assets (includes amounts related to VIEs)	881	1,137
Other (includes amounts related to VIEs)	242	125
Total current assets	3,895	4,085
Property, Plant and Equipment
Cost	53,491	50,260
Accumulated depreciation and amortization	(16,917)	(16,398)
Generation facilities to be retired, net	267	362
Net property, plant and equipment	36,841	34,224
Other Noncurrent Assets
Goodwill	3,655	3,655
Regulatory assets (includes amounts related to VIEs)	6,733	6,564
Nuclear decommissioning trust funds	3,590	3,162
Operating lease right-of-use assets, net	814
Other (includes amounts related to VIEs)	989	974
Total other noncurrent assets	15,781	14,355
Total Assets	56,517	52,664
Current Liabilities
Accounts payable	1,095	1,172
Accounts payable to affiliated companies	354	360
Notes payable to affiliated companies	1,789	1,235
Taxes accrued	271	109
Interest accrued	212	246
Current maturities of long-term debt (includes amounts related to VIEs)	1,276	1,672
Asset retirement obligations	478	514
Regulatory liabilities	296	280
Other	850	821
Total current liabilities	6,621	6,409
Long-Term Debt (includes amounts related to VIEs)	17,693	17,089
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	4,389	3,941
Asset retirement obligations	5,610	4,897
Regulatory liabilities	5,165	5,049
Operating lease liabilities	710
Accrued pension and other post-retirement benefit costs	455	521
Other (includes amounts related to VIEs)	361	351
Total other noncurrent liabilities	16,690	14,759
Equity
Additional paid-in capital	9,143	9,143
Retained earnings	6,236	5,131
Accumulated other comprehensive loss	(19)	(20)
Total Duke Energy Corporation stockholders' equity	15,360	14,254
Noncontrolling interests	3	3
Total equity	15,363	14,257
Total Liabilities and Equity	56,517	52,664
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	49	23
Receivables (net of allowance for doubtful accounts)	75	75
Receivables of VIEs (net of allowance for doubtful accounts)	564	547
Receivables from affiliated companies	34	23
Inventory	939	954
Regulatory assets (includes amounts related to VIEs)	515	703
Other (includes amounts related to VIEs)	95	62
Total current assets	2,271	2,387
Property, Plant and Equipment
Cost	33,594	31,459
Accumulated depreciation and amortization	(11,761)	(11,423)
Generation facilities to be retired, net	267	362
Net property, plant and equipment	22,100	20,398
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	4,363	4,111
Nuclear decommissioning trust funds	2,872	2,503
Operating lease right-of-use assets, net	397
Other (includes amounts related to VIEs)	595	612
Total other noncurrent assets	8,227	7,226
Total Assets	32,598	30,011
Current Liabilities
Accounts payable	550	660
Accounts payable to affiliated companies	198	278
Notes payable to affiliated companies	79	294
Taxes accrued	101	53
Interest accrued	89	116
Current maturities of long-term debt (includes amounts related to VIEs)	306	603
Asset retirement obligations	476	509
Regulatory liabilities	210	178
Other	416	408
Total current liabilities	2,425	3,099
Long-Term Debt (includes amounts related to VIEs)	8,593	7,451
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	2,316	2,119
Asset retirement obligations	5,038	4,311
Regulatory liabilities	4,152	3,955
Operating lease liabilities	360
Accrued pension and other post-retirement benefit costs	230	237
Investment tax credits	138	142
Other (includes amounts related to VIEs)	105	106
Total other noncurrent liabilities	12,339	10,870
Equity
Total member's equity	9,091	8,441
Total Liabilities and Equity	32,598	30,011
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	24	36
Receivables (net of allowance for doubtful accounts)	104	143
Receivables of VIEs (net of allowance for doubtful accounts)	478	362
Receivables from affiliated companies	1	28
Inventory	495	504
Regulatory assets (includes amounts related to VIEs)	367	434
Other (includes amounts related to VIEs)	42	46
Total current assets	1,511	1,553
Property, Plant and Equipment
Cost	19,887	18,792
Accumulated depreciation and amortization	(5,148)	(4,968)
Net property, plant and equipment	14,739	13,824
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	2,370	2,454
Nuclear decommissioning trust funds	718	659
Operating lease right-of-use assets, net	417
Other (includes amounts related to VIEs)	307	311
Total other noncurrent assets	3,812	3,424
Total Assets	20,062	18,801
Current Liabilities
Accounts payable	542	511
Accounts payable to affiliated companies	158	91
Notes payable to affiliated companies	356	108
Taxes accrued	175	74
Interest accrued	72	75
Current maturities of long-term debt (includes amounts related to VIEs)	621	270
Asset retirement obligations	2	5
Regulatory liabilities	87	102
Other	423	406
Total current liabilities	2,436	1,642
Long-Term Debt (includes amounts related to VIEs)	6,511	7,051
Other Noncurrent Liabilities
Deferred income taxes	2,199	1,986
Asset retirement obligations	572	586
Regulatory liabilities	1,013	1,094
Operating lease liabilities	350
Accrued pension and other post-retirement benefit costs	196	254
Other (includes amounts related to VIEs)	102	93
Total other noncurrent liabilities	4,432	4,013
Equity
Member's equity	6,683	6,097
Accumulated other comprehensive loss		(2)
Total member's equity	6,683	6,095
Total Liabilities and Equity	20,062	18,801
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	11	21
Receivables (net of allowance for doubtful accounts)	81	102
Receivables from affiliated companies	63	114
Notes receivable from affiliated companies	74
Inventory	128	126
Regulatory assets (includes amounts related to VIEs)	47	33
Other (includes amounts related to VIEs)	28	24
Total current assets	432	420
Property, Plant and Equipment
Cost	9,993	9,360
Accumulated depreciation and amortization	(2,785)	(2,717)
Net property, plant and equipment	7,208	6,643
Other Noncurrent Assets
Goodwill	920	920
Regulatory assets (includes amounts related to VIEs)	553	531
Operating lease right-of-use assets, net	22
Other (includes amounts related to VIEs)	48	41
Total other noncurrent assets	1,543	1,492
Total Assets	9,183	8,555
Current Liabilities
Accounts payable	266	316
Accounts payable to affiliated companies	69	78
Notes payable to affiliated companies	167	274
Taxes accrued	162	202
Interest accrued	29	22
Current maturities of long-term debt (includes amounts related to VIEs)	100	551
Asset retirement obligations	3	6
Regulatory liabilities	64	57
Other	74	74
Total current liabilities	934	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	901	817
Asset retirement obligations	82	87
Regulatory liabilities	793	840
Operating lease liabilities	21
Accrued pension and other post-retirement benefit costs	103	79
Other (includes amounts related to VIEs)	95	93
Total other noncurrent liabilities	1,995	1,916
Equity
Common stock	762	762
Additional paid-in capital	2,776	2,776
Retained earnings	97	(93)
Total Duke Energy Corporation stockholders' equity	3,635	3,445
Total Liabilities and Equity	9,183	8,555
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	20	24
Receivables (net of allowance for doubtful accounts)	56	52
Receivables from affiliated companies	85	122
Notes receivable from affiliated companies	213
Inventory	478	422
Regulatory assets (includes amounts related to VIEs)	91	175
Other (includes amounts related to VIEs)	29	35
Total current assets	972	830
Property, Plant and Equipment
Cost	16,137	15,443
Accumulated depreciation and amortization	(5,200)	(4,914)
Net property, plant and equipment	10,937	10,529
Other Noncurrent Assets
Regulatory assets (includes amounts related to VIEs)	1,088	982
Operating lease right-of-use assets, net	58
Other (includes amounts related to VIEs)	211	194
Total other noncurrent assets	1,357	1,176
Total Assets	13,266	12,535
Current Liabilities
Accounts payable	196	200
Accounts payable to affiliated companies	74	83
Notes payable to affiliated companies		167
Taxes accrued	29	43
Interest accrued	54	58
Current maturities of long-term debt (includes amounts related to VIEs)	651	63
Asset retirement obligations	165	109
Regulatory liabilities	39	25
Other	107	107
Total current liabilities	1,315	855
Long-Term Debt (includes amounts related to VIEs)	3,407	3,569
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	1,119	1,009
Asset retirement obligations	659	613
Regulatory liabilities	1,684	1,722
Operating lease liabilities	55
Accrued pension and other post-retirement benefit costs	157	115
Investment tax credits	161	147
Other (includes amounts related to VIEs)	57	16
Total other noncurrent liabilities	3,892	3,622
Equity
Total member's equity	4,502	4,339
Total Liabilities and Equity	13,266	12,535
Piedmont Natural Gas [Member]
Current Assets
Receivables (net of allowance for doubtful accounts)	78	266
Receivables from affiliated companies	10	22
Inventory	47	70
Regulatory assets (includes amounts related to VIEs)	48	54
Other (includes amounts related to VIEs)	122	19
Total current assets	305	431
Property, Plant and Equipment
Cost	8,234	7,486
Accumulated depreciation and amortization	(1,652)	(1,575)
Net property, plant and equipment	6,582	5,911
Other Noncurrent Assets
Goodwill	49	49
Regulatory assets (includes amounts related to VIEs)	306	303
Operating lease right-of-use assets, net	25
Investments in equity method unconsolidated affiliates	82	64
Other (includes amounts related to VIEs)	42	52
Total other noncurrent assets	504	468
Total Assets	7,391	6,810
Current Liabilities
Accounts payable	140	203
Accounts payable to affiliated companies	50	38
Notes payable to affiliated companies	262	198
Taxes accrued	33	84
Interest accrued	32	31
Current maturities of long-term debt (includes amounts related to VIEs)		350
Regulatory liabilities	77	37
Other	63	58
Total current liabilities	657	999
Long-Term Debt (includes amounts related to VIEs)	2,384	1,788
Other Noncurrent Liabilities
Deferred income taxes	663	551
Asset retirement obligations	20	19
Regulatory liabilities	1,154	1,181
Operating lease liabilities	24
Accrued pension and other post-retirement benefit costs	6	4
Other (includes amounts related to VIEs)	145	177
Total other noncurrent liabilities	2,012	1,932
Equity
Common stock	1,310	1,160
Retained earnings	1,028	931
Total Duke Energy Corporation stockholders' equity	2,338	2,091
Total Liabilities and Equity	7,391	$ 6,810
Series A Preferred Stock [Member]
Equity
Preferred stock	973
Series B Preferred Stock [Member]
Equity
Preferred stock	$ 990

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Allowance for doubtful accounts - receivables	$ 20	$ 16
Regulatory assets, current	1,723	2,005
Other, current assets	1,333	1,049
Regulatory assets, noncurrent	13,916	13,617
Other, noncurrent assets	2,905	2,935
Current maturities of long-term debt	3,096	3,406
Long-Term Debt	$ 54,818	$ 51,123
Common stock, par value (in usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	729,000,000	727,000,000
Other, noncurrent liabilities	$ 1,649	$ 1,650
Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	53	55
Regulatory assets, current	52	52
Other, current assets	188	162
Regulatory assets, noncurrent	1,002	1,041
Other, noncurrent assets	63	261
Current maturities of long-term debt	231	227
Long-Term Debt	4,060	3,998
Other, noncurrent liabilities	218	212
Duke Energy Carolinas [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	573	520
Other, current assets	19	72
Regulatory assets, noncurrent	3,587	3,457
Other, noncurrent assets	1,061	1,027
Current maturities of long-term debt	457	6
Long-Term Debt	11,001	10,633
Other, noncurrent liabilities	617	671
Duke Energy Carolinas [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	7	7
Progress Energy [Member]
Allowance for doubtful accounts - receivables	6	5
Regulatory assets, current	881	1,137
Other, current assets	242	125
Regulatory assets, noncurrent	6,733	6,564
Other, noncurrent assets	989	974
Current maturities of long-term debt	1,276	1,672
Long-Term Debt	$ 17,693	$ 17,089
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Other, noncurrent liabilities	$ 361	$ 351
Progress Energy [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	8	8
Regulatory assets, current	52	52
Other, current assets	16	39
Regulatory assets, noncurrent	1,002	1,041
Current maturities of long-term debt	54	53
Long-Term Debt	1,631	1,636
Duke Energy Progress [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	515	703
Other, current assets	95	62
Regulatory assets, noncurrent	4,363	4,111
Other, noncurrent assets	595	612
Current maturities of long-term debt	306	603
Long-Term Debt	8,593	7,451
Other, noncurrent liabilities	105	106
Duke Energy Progress [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	5	5
Duke Energy Florida [Member]
Allowance for doubtful accounts - receivables	3	3
Regulatory assets, current	367	434
Other, current assets	42	46
Regulatory assets, noncurrent	2,370	2,454
Other, noncurrent assets	307	311
Current maturities of long-term debt	621	270
Long-Term Debt	6,511	7,051
Other, noncurrent liabilities	102	93
Duke Energy Florida [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	3	3
Regulatory assets, current	52	52
Other, current assets	16	39
Regulatory assets, noncurrent	1,002	1,041
Current maturities of long-term debt	54	53
Long-Term Debt	1,306	1,336
Duke Energy Ohio [Member]
Allowance for doubtful accounts - receivables	4	2
Regulatory assets, current	47	33
Other, current assets	28	24
Regulatory assets, noncurrent	553	531
Other, noncurrent assets	48	41
Current maturities of long-term debt	100	551
Long-Term Debt	$ 2,594	$ 1,589
Common stock, par value (in usd per share)	$ 8.50	$ 8.50
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares outstanding	90,000,000	90,000,000
Other, noncurrent liabilities	$ 95	$ 93
Duke Energy Indiana [Member]
Allowance for doubtful accounts - receivables	3	2
Regulatory assets, current	91	175
Other, current assets	29	35
Regulatory assets, noncurrent	1,088	982
Other, noncurrent assets	211	194
Current maturities of long-term debt	651	63
Long-Term Debt	3,407	3,569
Other, noncurrent liabilities	57	16
Piedmont Natural Gas [Member]
Allowance for doubtful accounts - receivables	5	2
Regulatory assets, current	48	54
Other, current assets	122	19
Regulatory assets, noncurrent	306	303
Other, noncurrent assets	42	52
Current maturities of long-term debt		350
Long-Term Debt	$ 2,384	$ 1,788
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Other, noncurrent liabilities	$ 145	$ 177
Series A Preferred Stock [Member]
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 [Member]
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

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 2,964	$ 2,190
Net income (attributable to parent)	3,047	2,202
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	3,831	3,447
Equity component of AFUDC	(99)	(175)
Losses on sales of other assets		87
Impairment charges	(16)	339
Deferred income taxes	736	1,099
Equity in earnings of unconsolidated affiliates	(137)	(49)
Accrued pension and other post-retirement benefit costs	13	46
Contributions to qualified pension plans	(77)	(141)
Payments for asset retirement obligations	(582)	(389)
Payment for disposal of other assets		(105)
Other rate case adjustments		37
Provision for rate refunds	61	375
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(4)	15
Receivables	62	(288)
Inventory	(3)	104
Other current assets	(134)	(648)
Increase (decrease) in
Accounts payable	(538)	389
Taxes accrued	125	122
Other current liabilities	(198)	(180)
Other assets	(264)	(585)
Other liabilities	(103)	(23)
Net cash provided by operating activities	5,637	5,667
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(8,084)	(6,752)
Contributions to equity method investments	(264)	(298)
Purchases of debt and equity securities	(3,105)	(2,763)
Proceeds from sales and maturities of debt and equity securities	3,092	2,718
Other	(272)	(175)
Net cash used in investing activities	(8,633)	(7,270)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	6,131	4,110
Proceeds from the issuance of preferred stock	1,963
Proceeds from the issuance of common stock	41	834
Payments for the redemption of long-term debt	(2,737)	(2,278)
Proceeds from the issuance of short-term debt with original maturities greater than 90 days	339	243
Payments for the redemption of short-term debt with original maturities greater than 90 days	(479)	(207)
Notes payable and commercial paper	(879)	638
Contributions from noncontrolling interests	615
Dividends paid	(1,990)	(1,835)
Other	(17)	42
Net cash provided by financing activities	2,987	1,547
Net decrease in cash, cash equivalents and restricted cash	(9)	(56)
Cash, cash equivalents and restricted cash at beginning of period	591	505
Cash, cash equivalents and restricted cash at end of period	582	449
Significant non-cash transactions:
Accrued capital expenditures	1,073	1,016
Non-cash dividends	81	79
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	1,184	936
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,227	1,084
Equity component of AFUDC	(29)	(57)
Losses on sales of other assets		1
Impairment charges	11	191
Deferred income taxes	96	266
Accrued pension and other post-retirement benefit costs	(5)	3
Contributions to qualified pension plans	(7)	(46)
Payments for asset retirement obligations	(234)	(174)
Provision for rate refunds	34	163
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(7)	2
Receivables	(80)	(154)
Receivable from affiliated companies	74	(63)
Inventory	5	(11)
Other current assets	(117)	(54)
Increase (decrease) in
Accounts payable	(284)	69
Accounts payable to affiliated companies	(56)	(67)
Taxes accrued	91	(47)
Other current liabilities	44	(129)
Other assets	2	18
Other liabilities	(43)	(47)
Net cash provided by operating activities	1,906	1,884
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,984)	(2,006)
Purchases of debt and equity securities	(1,658)	(1,386)
Proceeds from sales and maturities of debt and equity securities	1,658	1,386
Other	(80)	(103)
Net cash used in investing activities	(2,064)	(2,109)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	819	991
Payments for the redemption of long-term debt	(5)	(704)
Notes payable to affiliated companies	(390)	700
Distributions to parent	(275)	(750)
Other	(1)	(1)
Net cash provided by financing activities	148	236
Net decrease in cash, cash equivalents and restricted cash	(10)	11
Cash, cash equivalents and restricted cash at beginning of period	33	16
Cash, cash equivalents and restricted cash at end of period	23	27
Significant non-cash transactions:
Accrued capital expenditures	261	299
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	1,098	910
Net income (attributable to parent)	1,098	904
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,649	1,458
Equity component of AFUDC	(48)	(80)
Losses on sales of other assets		(23)
Impairment charges	(25)	34
Deferred income taxes	342	342
Accrued pension and other post-retirement benefit costs	14	18
Contributions to qualified pension plans	(57)	(45)
Payments for asset retirement obligations	(309)	(164)
Other rate case adjustments		37
Provision for rate refunds	13	101
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	9	14
Receivables	(128)	(316)
Receivable from affiliated companies	135	16
Inventory	45	119
Other current assets	79	(156)
Increase (decrease) in
Accounts payable	(64)	427
Accounts payable to affiliated companies	(6)	76
Taxes accrued	150	143
Other current liabilities	(96)	(28)
Other assets	(281)	(668)
Other liabilities	(90)	(34)
Net cash provided by operating activities	2,430	2,181
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,866)	(2,689)
Purchases of debt and equity securities	(1,304)	(1,216)
Proceeds from sales and maturities of debt and equity securities	1,300	1,225
Net proceeds from the sales of other assets		20
Notes receivable from affiliated companies		(205)
Other	(130)	(142)
Net cash used in investing activities	(3,000)	(3,007)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,295	1,785
Payments for the redemption of long-term debt	(1,263)	(719)
Notes payable to affiliated companies	554	(11)
Dividends to parent		(250)
Other	8	(3)
Net cash provided by financing activities	594	802
Net decrease in cash, cash equivalents and restricted cash	24	(24)
Cash, cash equivalents and restricted cash at beginning of period	112	87
Cash, cash equivalents and restricted cash at end of period	136	63
Significant non-cash transactions:
Accrued capital expenditures	400	441
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	650	532
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	996	869
Equity component of AFUDC	(44)	(41)
Losses on sales of other assets		(9)
Impairment charges		33
Deferred income taxes	144	187
Accrued pension and other post-retirement benefit costs	2	11
Contributions to qualified pension plans	(4)	(25)
Payments for asset retirement obligations	(288)	(133)
Other rate case adjustments		37
Provision for rate refunds	13	101
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(4)	3
Receivables	(9)	(154)
Receivable from affiliated companies	(11)	(3)
Inventory	15	62
Other current assets	65	(239)
Increase (decrease) in
Accounts payable	(54)	325
Accounts payable to affiliated companies	(80)	73
Taxes accrued	37	28
Other current liabilities	(17)	(27)
Other assets	(197)	(358)
Other liabilities	33	11
Net cash provided by operating activities	1,247	1,283
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,592)	(1,526)
Purchases of debt and equity securities	(656)	(831)
Proceeds from sales and maturities of debt and equity securities	632	807
Net proceeds from the sales of other assets		20
Notes receivable from affiliated companies		(52)
Other	(56)	(82)
Net cash used in investing activities	(1,672)	(1,664)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,270	796
Payments for the redemption of long-term debt	(603)	(2)
Notes payable to affiliated companies	(215)	(240)
Dividends to parent		(175)
Other	(1)	(1)
Net cash provided by financing activities	451	378
Net decrease in cash, cash equivalents and restricted cash	26	(3)
Cash, cash equivalents and restricted cash at beginning of period	23	20
Cash, cash equivalents and restricted cash at end of period	49	17
Significant non-cash transactions:
Accrued capital expenditures	182	261
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	586	514
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	647	581
Equity component of AFUDC	(4)	(40)
Impairment charges	(25)	1
Deferred income taxes	164	169
Accrued pension and other post-retirement benefit costs	8	4
Contributions to qualified pension plans	(53)	(20)
Payments for asset retirement obligations	(21)	(31)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	9	7
Receivables	(119)	(163)
Receivable from affiliated companies	27	(18)
Inventory	29	57
Other current assets	100	51
Increase (decrease) in
Accounts payable	(11)	101
Accounts payable to affiliated companies	67	9
Taxes accrued	101	198
Other current liabilities	(77)	1
Other assets	(81)	(308)
Other liabilities	(127)	(58)
Net cash provided by operating activities	1,220	1,055
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,274)	(1,162)
Purchases of debt and equity securities	(648)	(385)
Proceeds from sales and maturities of debt and equity securities	668	418
Notes receivable from affiliated companies		(80)
Other	(73)	(61)
Net cash used in investing activities	(1,327)	(1,270)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	25	989
Payments for the redemption of long-term debt	(210)	(717)
Notes payable to affiliated companies	248
Distributions to parent		(75)
Other	9	(1)
Net cash provided by financing activities	72	196
Net decrease in cash, cash equivalents and restricted cash	(35)	(19)
Cash, cash equivalents and restricted cash at beginning of period	75	53
Cash, cash equivalents and restricted cash at end of period	40	34
Significant non-cash transactions:
Accrued capital expenditures	218	180
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	190	121
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	202	199
Equity component of AFUDC	(9)	(10)
Losses on sales of other assets		106
Deferred income taxes	68	9
Accrued pension and other post-retirement benefit costs	1	3
Contributions to qualified pension plans	(2)
Payments for asset retirement obligations	(7)	(3)
Provision for rate refunds	5	23
(Increase) decrease in
Receivables	24	(44)
Receivable from affiliated companies	51	62
Inventory	(2)	(2)
Other current assets	(15)	12
Increase (decrease) in
Accounts payable	(40)	(47)
Accounts payable to affiliated companies	(9)	(8)
Taxes accrued	(40)	(31)
Other current liabilities	(4)	19
Other assets	(10)	3
Other liabilities	(25)	(17)
Net cash provided by operating activities	378	395
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(714)	(588)
Notes receivable from affiliated companies	(74)	14
Other	(45)	(62)
Net cash used in investing activities	(833)	(636)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,003
Payments for the redemption of long-term debt	(451)	(3)
Notes payable to affiliated companies	(107)	239
Net cash provided by financing activities	445	236
Net decrease in cash, cash equivalents and restricted cash	(10)	(5)
Cash, cash equivalents and restricted cash at beginning of period	21	12
Cash, cash equivalents and restricted cash at end of period	11	7
Significant non-cash transactions:
Accrued capital expenditures	100	83
Non-cash equity contribution from parent		106
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	363	317
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	395	388
Equity component of AFUDC	(13)	(28)
Impairment charges		30
Deferred income taxes	108	94
Accrued pension and other post-retirement benefit costs	3	5
Contributions to qualified pension plans	(2)	(8)
Payments for asset retirement obligations	(31)	(49)
Provision for rate refunds		58
(Increase) decrease in
Receivables	1	1
Receivable from affiliated companies	37	27
Inventory	(56)	16
Other current assets	91	(59)
Increase (decrease) in
Accounts payable	1	28
Accounts payable to affiliated companies	(9)	(6)
Taxes accrued	(14)	(51)
Other current liabilities	(12)	6
Other assets	(73)	29
Other liabilities	62	(13)
Net cash provided by operating activities	851	785
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(663)	(619)
Purchases of debt and equity securities	(19)	(42)
Proceeds from sales and maturities of debt and equity securities	15	18
Notes receivable from affiliated companies	(213)
Other	(33)	3
Net cash used in investing activities	(913)	(640)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	485
Payments for the redemption of long-term debt	(60)	(1)
Notes payable to affiliated companies	(167)	40
Distributions to parent	(200)	(175)
Other		(1)
Net cash provided by financing activities	58	(137)
Net decrease in cash, cash equivalents and restricted cash	(4)	8
Cash, cash equivalents and restricted cash at beginning of period	24	9
Cash, cash equivalents and restricted cash at end of period	20	17
Significant non-cash transactions:
Accrued capital expenditures	82	71
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	97	81
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	129	120
Deferred income taxes	110	2
Equity in earnings of unconsolidated affiliates	(6)	(6)
Accrued pension and other post-retirement benefit costs	(7)	(3)
Contributions to qualified pension plans	(1)
Provision for rate refunds	9	31
(Increase) decrease in
Receivables	192	192
Receivable from affiliated companies	12	(3)
Inventory	23	16
Other current assets	(95)	58
Increase (decrease) in
Accounts payable	(93)	(48)
Accounts payable to affiliated companies	12	14
Taxes accrued	(51)	11
Other current liabilities	(6)	8
Other assets	(4)	(4)
Other liabilities	(4)	(5)
Net cash provided by operating activities	317	464
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(751)	(497)
Contributions to equity method investments	(16)
Notes receivable from affiliated companies		(11)
Other	(10)	(5)
Net cash used in investing activities	(777)	(513)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	596	100
Payments for the redemption of long-term debt	(350)
Notes payable to affiliated companies	64	(364)
Capital contributions from parent	150	300
Net cash provided by financing activities	460	36
Net decrease in cash, cash equivalents and restricted cash		(13)
Cash, cash equivalents and restricted cash at beginning of period		19
Cash, cash equivalents and restricted cash at end of period		6
Significant non-cash transactions:
Accrued capital expenditures	$ 121	$ 89

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions		Total		Preferred Stock [Member]	Common Stockholders' Equity [Member]		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]		Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]		Net Unrealized (Losses) Gains on Available for Sale Securities [Member]		Pension and OPEB Adjustments [Member]		Noncontrolling Interest [Member]		Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member]Member's Equity [Member]	Duke Energy Carolinas [Member]Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]	Progress Energy [Member]	Progress Energy [Member]Common Stockholders' Equity [Member]	Progress Energy [Member]Additional Paid-in Capital [Member]	Progress Energy [Member]Retained Earnings [Member]		Progress Energy [Member]Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]		Progress Energy [Member]Net Unrealized (Losses) Gains on Available for Sale Securities [Member]		Progress Energy [Member]Pension and OPEB Adjustments [Member]		Progress Energy [Member]Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]Member's Equity [Member]		Duke Energy Florida [Member]Net Unrealized (Losses) Gains on Available for Sale Securities [Member]		Duke Energy Ohio [Member]		Duke Energy Ohio [Member]Common Stock [Member]	Duke Energy Ohio [Member]Additional Paid-in Capital [Member]		Duke Energy Ohio [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]	Piedmont Natural Gas [Member]	Piedmont Natural Gas [Member]Common Stock [Member]	Piedmont Natural Gas [Member]Retained Earnings [Member]	Series A Preferred Stock [Member]		Series A Preferred Stock [Member]Preferred Stock [Member]	[5]	Series A Preferred Stock [Member]Common Stockholders' Equity [Member]	[5]	Series B Preferred Stock [Member]		Series B Preferred Stock [Member]Preferred Stock [Member]		Series B Preferred Stock [Member]Common Stockholders' Equity [Member]	[6]	Common Stock [Member]	Common Stock [Member]Common Stockholders' Equity [Member]	Common Stock [Member]Common Stock [Member]	Common Stock [Member]Additional Paid-in Capital [Member]
Beginning Balance at Dec. 31, 2017		$ 41,737			$ 41,739		$ 1	$ 38,792	$ 3,013		$ (10)		$ 12		$ (69)		$ (2)					$ 13,465	$ 13,468	$ 9,143	$ 4,350		$ (18)		$ 5		$ (12)		$ (3)
Beginning Balance, in shares at Dec. 31, 2017							700,000,000
Beginning Balance (member's equity) at Dec. 31, 2017																			$ 11,361	$ 11,368	$ (7)													$ 7,949	$ 5,618	$ 5,614		$ 4								$ 4,121
Beginning Balance (parent) at Dec. 31, 2017																																								$ 3,163		$ 762	$ 2,670		$ (269)		$ 1,662	$ 860	$ 802
Net income (attributable to parent)		2,202																	936	936		904												532	514	514				121					121	317	81		81
Net Income		2,190																				910	904		904								6
Net income		2,190			2,202				2,202								(12)
Other comprehensive income (loss)		13			13						15		(5)		3				1		1	6	6				5		(1)		2				(1)			(1)
Stock issuances, shares																																																																13,000,000
Stock issuances																																																														$ 955	$ 955		$ 955
Common stock dividends		(1,914)			(1,914)				(1,914)										(750)	(750)		(250)	(250)		(250)									(175)	(75)	(75)										(175)
Distributions to noncontrolling interest in subsidiaries		(1)															(1)					(1)											(1)
Other		33	[1]						12	[1]			(12)	[1]			33	[1]							5	[2]			(5)	[2]						5	[3]	(5)	[3]	106	[4]		106	[4]			300	300
Ending Balance at Sep. 30, 2018		43,013			42,995		$ 1	39,747	3,313		5		(5)		(66)		18					14,130	14,128	9,143	5,009		(13)		(1)		(10)		2
Ending Balance, in shares at Sep. 30, 2018							713,000,000
Ending Balance (member's equity) at Sep. 30, 2018																			11,548	11,554	(6)													8,306	6,056	6,058		(2)								4,263
Ending Balance (parent) at Sep. 30, 2018																																								3,390		762	2,776		(148)		2,043	1,160	883
Beginning Balance at Jun. 30, 2018		42,515			42,507		$ 1	39,682	2,894		2		(5)		(67)		8					13,972	13,972	9,143	4,855		(15)		(1)		(10)
Beginning Balance, in shares at Jun. 30, 2018							712,000,000
Beginning Balance (member's equity) at Jun. 30, 2018																			11,302	11,308	(6)													8,265	5,888	5,890		(2)								4,244
Beginning Balance (parent) at Jun. 30, 2018																																								3,290		762	2,776		(248)		2,064	1,160	904
Net income (attributable to parent)		1,082																	496	496		404												216	243	243				100					100	119	(21)		(21)
Net Income		1,066																				406	404		404								2
Net income		1,066			1,082				1,082								(16)
Other comprehensive income (loss)		4			4						3				1							2	2				2
Stock issuances, shares																																																																1,000,000
Stock issuances																																																														65	65		65
Common stock dividends		(663)			(663)				(663)										(250)	(250)		(250)	(250)		(250)									(175)	(75)	(75)										(100)
Other		26															26
Ending Balance at Sep. 30, 2018		43,013			42,995		$ 1	39,747	3,313		5		(5)		(66)		18					14,130	14,128	9,143	5,009		(13)		(1)		(10)		2
Ending Balance, in shares at Sep. 30, 2018							713,000,000
Ending Balance (member's equity) at Sep. 30, 2018																			11,548	11,554	(6)													8,306	6,056	6,058		(2)								4,263
Ending Balance (parent) at Sep. 30, 2018																																								$ 3,390		762	2,776		(148)		$ 2,043	1,160	883
Beginning Balance at Dec. 31, 2018		$ 43,834		$ 0	43,817		$ 1	40,795	3,113		(14)		(3)		(75)		17					$ 14,257	14,254	9,143	5,131		(12)		(1)		(7)		3
Beginning Balance, in shares at Dec. 31, 2018		727,000,000					727,000,000															100																		90,000,000							100
Beginning Balance (member's equity) at Dec. 31, 2018																			11,683	11,689	(6)													8,441	6,095	6,097		(2)								4,339
Beginning Balance (parent) at Dec. 31, 2018		$ 43,817																				$ 14,254																		$ 3,445		762	2,776		(93)		$ 2,091	1,160	931
Net income (attributable to parent)		3,047																	1,184	1,184		1,098												650	586	586				$ 190					190	363	97		97
Net Income		2,964																				1,098	1,098		1,098
Net income		2,937			3,047				3,047								(110)
Other comprehensive income (loss)		(47)			(47)						(58)		10		1							8	8				4		2		2				2			2
Stock issuances, shares																																																																2,000,000
Stock issuances																																																		$ 973	[5]	$ 973		$ 973		$ 990	[6]	$ 990	[6]	$ 990		158	158		158
Common stock dividends		(2,044)			(2,044)				(2,044)										(275)	(275)																										(200)
Sale of noncontrolling interest	[7]	408			(455)						10						863																																																$ (465)
Distributions to noncontrolling interest in subsidiaries		(1)															(1)
Other		(1)	[8]		(1)	[8]			23	[8]	(6)	[8]	(1)	[8]	(17)	[8]			(1)		(1)				7	[9]	(4)	[9]	(1)	[9]	(2)	[9]															$ 150	150
Contribution from noncontrolling interest in subsidiaries	[10]	200															200
Ending Balance at Sep. 30, 2019		$ 47,407		1,963	46,438		$ 1	40,488	4,139		(68)		6		(91)		969					$ 15,363	15,360	9,143	6,236		(12)				(7)		3
Ending Balance, in shares at Sep. 30, 2019																																																		40,000,000						1,000,000
Ending Balance, in shares at Sep. 30, 2019		729,000,000					729,000,000															100																		90,000,000							100
Ending Balance (member's equity) at Sep. 30, 2019																			12,591	12,598	(7)													9,091	6,683	6,683										4,502
Ending Balance (parent) at Sep. 30, 2019		$ 46,438																				$ 15,360																		$ 3,635		762	2,776		97		$ 2,338	1,310	1,028
Beginning Balance at Jun. 30, 2019		45,332		973	45,213		$ 1	40,885	3,502		(63)		4		(89)		119					14,839	14,837	9,143	5,715		(13)				(8)		2
Beginning Balance, in shares at Jun. 30, 2019							728,000,000
Beginning Balance (member's equity) at Jun. 30, 2019																			12,276	12,283	(7)													8,813	6,393	6,394		(1)								4,546
Beginning Balance (parent) at Jun. 30, 2019																																								3,561		762	2,776		23		2,356	1,310	1,046
Net income (attributable to parent)		1,327																	590	590		521												278	289	289				$ 74					74	156	$ (18)		(18)
Net Income		1,323																				521	521		521
Net income		1,308			1,327				1,327								(19)
Other comprehensive income (loss)		(15)			(15)						(15)		2		(2)							2	2				1		1						1			$ 1
Stock issuances, shares																																																										1,000,000							1,000,000
Stock issuances																																																								$ 990	[6]	$ 990	[6]	$ 990		$ 69	$ 69		$ 69
Common stock dividends		(690)			(690)				(690)										(275)	(275)																										(200)
Sale of noncontrolling interest	[7]	408			(455)			(465)			10						863
Other		(2)			(1)			(1)									(1)					1							$ (1)		1		1
Contribution from noncontrolling interest in subsidiaries	[10]	7															7
Ending Balance at Sep. 30, 2019		$ 47,407		$ 1,963	$ 46,438		$ 1	$ 40,488	$ 4,139		$ (68)		$ 6		$ (91)		$ 969					$ 15,363	$ 15,360	$ 9,143	$ 6,236		$ (12)				$ (7)		$ 3
Ending Balance, in shares at Sep. 30, 2019																																																		40,000,000						1,000,000
Ending Balance, in shares at Sep. 30, 2019		729,000,000					729,000,000															100																		90,000,000							100
Ending Balance (member's equity) at Sep. 30, 2019																			$ 12,591	$ 12,598	$ (7)													$ 9,091	$ 6,683	$ 6,683										$ 4,502
Ending Balance (parent) at Sep. 30, 2019		$ 46,438																				$ 15,360																		$ 3,635		$ 762	$ 2,776		$ 97		$ 2,338	$ 1,310	$ 1,028
[1]	Amounts in Retained Earnings and Accumulated Other Comprehensive (Loss) Income represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement.
[2]	Amounts in Retained Earnings and Accumulated Other Comprehensive (Loss) Income represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement.
[3]	Amounts in Member's Equity and Accumulated Other Comprehensive Income (Loss) represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement.
[4]	Represents a non-cash settlement through equity of an intercompany payable from Duke Energy Ohio to its parent.
[5]	Duke Energy issued 40 million depositary shares of preferred stock, series A, in the first quarter of 2019.
[6]	Duke Energy issued 1 million shares of preferred stock, series B, in the third quarter of 2019.
[7]	See Note 2 for additional discussion of the transaction.
[8]	Amounts in Retained Earnings and Accumulated Other Comprehensive (Loss) Income 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.
[9]	Amounts in Retained Earnings and Accumulated Other Comprehensive (Loss) Income 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]	Relates to tax equity financing activity in the Commercial Renewables segment. See Note 1 for additional discussion.

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Changes in Equity (Parenthetical)	3 Months Ended
	Mar. 31, 2019shares
Series A Preferred Stock [Member] | Preferred Stock [Member]
Stock issuances, shares	40,000,000

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Index to Combined Notes to Condensed Consolidated Financial Statements The unaudited notes to the Condensed Consolidated Financial Statements that follow are a combined presentation. The following list indicates the registrants to which the footnotes apply. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 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. BASIS OF PRESENTATION These Condensed Consolidated Financial Statements have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all information and notes required by GAAP for annual financial statements and should be read in conjunction with the Consolidated Financial Statements in the Duke Energy Registrants’ combined Annual Report on Form 10-K for the year ended December 31, 2018 . The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants make any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. These Condensed Consolidated Financial Statements, in the opinion of the respective companies’ management, reflect all normal recurring adjustments necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors. In preparing financial statements that conform to GAAP, management 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. BASIS OF CONSOLIDATION These Condensed 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 13 for additional information on VIEs. These Condensed Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. 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 Condensed Consolidated Balance Sheet. Several operating agreements of Duke Energy's subsidiaries with noncontrolling interest are subject to allocations of earnings, 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 book profit 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 profit or loss allocated to each owner for the reporting period. Duke Energy’s North Rosamond solar farm commenced commercial operations resulting in the allocation of losses to the noncontrolling tax equity members of $12 million and $86 million for the three and nine months ended September 30, 2019 , respectively, utilizing the HLBV method. 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 a 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. OTHER CURRENT ASSETS Included in Other within Current Assets on the Piedmont Condensed Consolidated Balance Sheets are income taxes receivable of $90 million and $11 million as of September 30, 2019 , and December 31, 2018 , respectively, and prepaid assets of $30 million and $5 million as of September 30, 2019 , and December 31, 2018 , respectively. The income taxes receivable relates to increased projected NOL utilization for Piedmont as well as intercompany tax settlements. The prepaid assets relate to replenishment of depleted natural gas supply as required by natural gas supply asset management contracts. CASH, CASH EQUIVALENTS AND RESTRICTED CASH Duke Energy, Progress Energy and Duke Energy Florida have restricted cash balances related primarily to collateral assets, escrow deposits and VIEs. See Note 13 for additional information. Restricted cash amounts are included in Other within Current Assets and Other Noncurrent Assets on the Condensed Consolidated Balance Sheets. The following table presents the components of cash, cash equivalents and restricted cash included in the Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 379 $ 82 $ 24 $ 442 $ 67 $ 36 Other 163 16 16 141 39 39 Other Noncurrent Assets Other 40 38 — 8 6 — Total cash, cash equivalents and restricted cash $ 582 $ 136 $ 40 $ 591 $ 112 $ 75 INVENTORY Provisions for inventory write-offs were not material at September 30, 2019 , and December 31, 2018 . The components of inventory are presented in the tables below. September 30, 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 $ 2,284 $ 749 $ 1,056 $ 710 $ 346 $ 75 $ 325 $ 4 Coal 490 153 172 118 54 12 152 — Natural gas, oil and other fuel 333 41 206 111 95 41 1 43 Total inventory $ 3,107 $ 943 $ 1,434 $ 939 $ 495 $ 128 $ 478 $ 47 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 fuel 355 42 218 114 103 28 1 68 Total inventory $ 3,084 $ 948 $ 1,459 $ 954 $ 504 $ 126 $ 422 $ 70 NEW ACCOUNTING STANDARDS Except as noted below, the new accounting standards adopted for 2018 and 2019 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 September 30, 2019 , and an immaterial impact to the Duke Energy Registrants' results of operations for the three and nine months ended September 30, 2019 , and cash flows for the nine months ended September 30, 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 has 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 5 for further information. The following new accounting standard has been issued but not yet adopted by the Duke Energy Registrants as of September 30, 2019 . Credit Losses. In June 2016, the FASB issued new accounting guidance for credit losses. This guidance establishes the new CECL 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.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS 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 primarily includes Duke Energy's regulated electric utilities in the Carolinas, Florida and the Midwest. 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. 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. 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 Condensed Consolidated Statements of Operations. The difference between the fair value of the consideration received and the carrying value of the noncontrolling interest claim on net assets of $465 million , net of a tax benefit of $8 million , was recorded in equity. During 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 and further testing was not required. A continued decline in energy market pricing would likely result in a future impairment. 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, Duke Energy’s wholly owned captive insurance company, Bison, and Duke Energy's interest in NMC. Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Three Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 6,569 $ 225 $ 138 $ 6,932 $ 8 $ — $ 6,940 Intersegment revenues 8 24 — 32 17 (49 ) — Total revenues $ 6,577 $ 249 $ 138 $ 6,964 $ 25 $ (49 ) $ 6,940 Segment income (loss) (a) $ 1,385 $ 26 $ 40 $ 1,451 $ (124 ) $ — $ 1,327 Add back noncontrolling interests (b) (19 ) Add back preferred stock dividend 15 Net income $ 1,323 Segment assets $ 133,296 $ 13,424 $ 5,278 $ 151,998 $ 3,734 $ 185 $ 155,917 Three Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 6,253 $ 232 $ 127 $ 6,612 $ 16 $ — $ 6,628 Intersegment revenues 7 24 — 31 18 (49 ) — Total revenues $ 6,260 $ 256 $ 127 $ 6,643 $ 34 $ (49 ) $ 6,628 Segment income (loss) (c)(d)(e) $ 1,167 $ 17 $ (62 ) $ 1,122 $ (44 ) $ — $ 1,078 Add back noncontrolling interests (16 ) Loss from discontinued operations, net of tax 4 Net income $ 1,066 Nine Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 17,357 $ 1,239 $ 362 $ 18,958 $ 18 $ — $ 18,976 Intersegment revenues 24 72 — 96 53 (149 ) — Total revenues $ 17,381 $ 1,311 $ 362 $ 19,054 $ 71 $ (149 ) $ 18,976 Segment income (loss) (a) $ 2,944 $ 292 $ 139 $ 3,375 $ (328 ) $ — $ 3,047 Add back noncontrolling interests (b) (110 ) Add back preferred stock dividend 27 Net income $ 2,964 Nine Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 16,783 $ 1,229 $ 347 $ 18,359 $ 47 $ — $ 18,406 Intersegment revenues 23 72 — 95 54 (149 ) — Total revenues $ 16,806 $ 1,301 $ 347 $ 18,454 $ 101 $ (149 ) $ 18,406 Segment income (loss) (c)(d)(e)(f)(g)(h) $ 2,492 $ 161 $ (4 ) $ 2,649 $ (446 ) $ — $ 2,203 Add back noncontrolling interests (12 ) Loss from discontinued operations, net of tax (1 ) Net income $ 2,190 (a) Electric Utilities and Infrastructure includes a reduction of a prior year impairment at Citrus County CC related to the plant's cost cap. See Note 3 for additional information. (b) Includes the allocation of losses to noncontrolling tax equity members. See Note 1 for additional information. (c) All segments include adjustments of prior year tax estimates related to the Tax Act. (d) Commercial Renewables includes an impairment charge related to goodwill. (e) Other includes costs to achieve the Piedmont acquisition. (f) Electric Utilities and Infrastructure includes regulatory and legislative charges related to rate case orders, settlements or other actions of regulators or legislative bodies. See Note 3 for additional information. (g) Gas Utilities and Infrastructure includes an impairment of the investment in Constitution. See Note 3 for additional information. (h) Other includes the loss on the sale of Beckjord described below and a valuation allowance recorded against the AMT credits. In February 2018, Duke Energy sold Beckjord, a nonregulated facility retired during 2014, and recorded a pretax loss of $106 million within Gains (Losses) on Sales of Other Assets and Other, net and $1 million within Operation, maintenance and other on Duke Energy's Condensed Consolidated Statements of Operations for the nine months ended September 30, 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. Duke Energy Ohio Duke Energy Ohio has two reportable segments, Electric Utilities and Infrastructure and Gas Utilities and Infrastructure. The remainder of Duke Energy Ohio's operations is presented as Other. Three Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 408 $ 81 $ 489 $ — $ — $ 489 Segment income/Net (loss) income $ 62 $ 13 $ 75 $ (1 ) $ — $ 74 Segment assets $ 6,107 $ 3,049 $ 9,156 $ 30 $ (3 ) $ 9,183 Three Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 373 $ 84 $ 457 $ 12 $ 469 Segment income/Net income $ 85 $ 12 $ 97 $ 3 $ 100 Nine Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 1,099 $ 354 $ 1,453 $ — $ 1,453 Segment income/Net (loss) income $ 129 $ 65 $ 194 $ (4 ) $ 190 Nine Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 1,055 $ 361 $ 1,416 $ 36 $ 1,452 Segment income/Net (loss) income (a) $ 157 $ 64 $ 221 $ (100 ) $ 121 (a) Other includes the loss on the sale of Beckjord described above.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2019
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS 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 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 Lee 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 Condensed 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 order, Duke Energy Carolinas recorded a pretax charge of approximately $150 million to Impairment charges and Operation, maintenance and other on the Condensed 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’s brief was filed on April 26, 2019. The Appellee response briefs were filed on September 25, 2019. 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. 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, will be deferred with a return, subject to evaluation in a future rate proceeding, and that Duke Energy Carolinas will refile for consideration of the GIP in a new docket for resolution by January 1, 2020. The Stipulation was approved by the PSCSC on June 19, 2019. 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 intends to file a notice of appeal within 30 days of the date of the order with the South Carolina Supreme Court. Based on legal analysis and Duke Energy Carolinas' intention to file such an 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 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 their 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 (“Order”) 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 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 Carolinas will purchase all the capacity and energy generated by these facilities at the avoided cost for five years through power purchase agreements. Duke Energy Progress 2017 North Carolina Rate Case On June 1, 2017, Duke Energy Progress filed an application with the NCUC for a rate increase for retail customers of approximately $477 million , which represented an approximate 14.9% increase in annual base revenues. Subsequent to the filing, Duke Energy Progress adjusted the requested amount to $420 million , representing an approximate 13% increase. The request for rate increase was driven by capital investments subsequent to the previous base rate case, costs of complying with CCR regulations and the Coal Ash Act, costs relating to storm recovery, investments in customer service technologies and recovery of costs associated with renewable purchased power. On November 22, 2017, Duke Energy Progress 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. On February 23, 2018, the NCUC issued an order approving the stipulation. The order also impacted certain amounts that were similarly recorded on Duke Energy Carolinas' Condensed Consolidated Balance Sheets. As a result of the order, Duke Energy Progress and Duke Energy Carolinas recorded pretax charges of $68 million and $14 million , respectively, in the first quarter of 2018 to Impairment charges, Operation, maintenance and other and Interest Expense on the Condensed Consolidated Statements of Operations. Revised customer rates became effective on March 16, 2018. On May 15, 2018, the Public Staff filed a Notice of Cross Appeal to the North Carolina Supreme Court from the NCUC's February 23, 2018, Order. The Public Staff contends the NCUC’s order should be reversed and remanded, as it is affected by errors of law, and is unsupported by competent, material and substantial evidence in view of the entire record as submitted. The North Carolina Attorney General and Sierra Club also filed Notices of Appeal to the North Carolina Supreme Court from the February 23, 2018, Order. 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 Progress and Duke Energy Carolinas appeals and enter an order adopting the parties’ proposed briefing schedule as set out in the filing. Appellant’s brief was filed on April 26, 2019. The Appellee response briefs were filed on September 25, 2019. Duke Energy Progress cannot predict the outcome of this matter. 2019 North Carolina Rate Case On October 30, 2019, Duke Energy Progress filed an application with the NCUC for a net rate increase for retail customers of approximately $464 million , which represents an approximate 12.3% increase in annual base revenues. The gross rate case revenue increase request is $586 million , which is offset by riders of $122 million , primarily an EDIT rider of $120 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 Progress seeks to defer and recover incremental Hurricane Dorian storm costs in this proceeding and requests rates be effective no later than September 1, 2020. Duke Energy Progress cannot predict the outcome of this matter. Hurricane Dorian Hurricane Dorian reached the Carolinas in September 2019 as a Category 2 hurricane making landfall within Duke Energy Progress’ service territory. Approximately 270,000 North Carolina customers and 30,000 South Carolina customers were impacted by the slow-moving storm that brought high winds, tornadoes and heavy rain. With storm-response mobilization occurring in preparation for the storm and the assistance of mutual aid partners, full restoration was accomplished within four days for all customers able to receive service. Total estimated incremental operation and maintenance expenses incurred to repair and restore the system are approximately $208 million with an additional $10 million in capital investments made for restoration efforts. Approximately $182 million of the operation and maintenance expenses are deferred in Regulatory assets within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets as of September 30, 2019. The balance of operation and maintenance expenses are included in Operation, maintenance and other on the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2019. 2018 South Carolina Rate Case On November 8, 2018, Duke Energy Progress filed an application with the PSCSC for a rate increase for retail customers of approximately $59 million , which represents an approximate 10.3% increase in annual base revenues. The request for rate increase was driven by capital investments and environmental compliance progress made by Duke Energy Progress since its previous rate case, including the further implementation of Duke Energy Progress’ 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 a decrease resulting from the Tax Act of $17 million to reflect the change in ongoing tax expense, primarily the reduction in the federal income tax rate from 35% to 21%. The request also included $10 million to return EDIT resulting from the federal tax rate change and deferred revenues since January 2018 related to the change (EDIT Rider) and a $12 million increase due to the expiration of EDITs related to reductions in North Carolina state income taxes allocable to South Carolina. Duke Energy Progress also requested approval of its proposed GIP, approval of a Prepaid Advantage Program and a variety of accounting orders related to ongoing costs for environmental compliance, including recovery over a five -year period of $51 million of deferred coal ash related compliance costs, AMI deployment, grid investments between rate changes and regulatory asset treatment related to the retirement of a generating plant located in Asheville, North Carolina. Finally, Duke Energy Progress sought approval to establish a reserve and accrual for end-of-life nuclear costs for materials and supplies and nuclear fuel. 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 Progress. Subsequently, on March 12, 2019, the ORS and Duke Energy Carolinas executed a Stipulation resolving the ORS’s motion, and Duke Energy Progress agreed to the Stipulation, as did other parties in the rate case. The Stipulation provides that costs incurred for the GIP after January 1, 2019, will be deferred with a return, with all costs subject to evaluation in a future rate proceeding, and that Duke Energy Progress will refile for consideration of the GIP in a new docket for resolution by January 1, 2020. The Stipulation was approved by the PSCSC on June 19, 2019. After hearings in April 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 recovery of $4 million of coal ash costs over a five-year period with a return at Duke Energy Progress' WACC; • Denial of recovery of $65 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 $17 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 $12 million decrease through the EDIT Tax Savings Rider resulting from the federal tax rate change and deferred revenues since January 2018 related to the change, to be returned in accordance with 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 three-year period for the deferred revenues; and • Approval of a $12 million increase due to the expiration of EDIT related to reductions in the North Carolina state income tax rate from 6.9% to 2.5%. As a result of the order, revised customer rates were effective June 1, 2019. On May 31, 2019, Duke Energy Progress filed a Petition for Rehearing or Reconsideration of that order contending substantial rights of Duke Energy Progress 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 Progress' 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, but allowing additional litigation-related costs. As a result of the Directive allowing litigation-related costs, customer rates were revised effective July 1, 2019. An order detailing the commission's decision in the Directive was issued on October 18, 2019. Duke Energy Progress intends to file a notice of appeal within 30 days of the date of the order with the South Carolina Supreme Court. Based on legal analysis and Duke Energy Progress' intention to file such an appeal, Duke Energy Progress has not recorded an adjustment for its deferred coal ash costs. Duke Energy Progress cannot predict the outcome of this matter. Western Carolinas Modernization Plan On November 4, 2015, Duke Energy Progress announced a Western Carolinas Modernization Plan, which included retirement of the existing Asheville coal-fired plant, the construction of two 280‑MW combined-cycle natural gas plants having dual-fuel capability, with the option to build a third natural gas simple cycle unit in 2023 based upon the outcome of initiatives to reduce the region's power demand. The plan also included upgrades to existing transmission lines and substations, installation of solar generation and a pilot battery storage project. These investments will be made within the next seven years. Duke Energy Progress worked with the local natural gas distribution company to upgrade and lease an existing natural gas pipeline to serve the natural gas plant. The lease for the new pipeline became effective on March 2, 2019. On March 28, 2016, the NCUC issued an order approving a CPCN for the new combined-cycle natural gas plants, but is requiring Duke Energy Progress to refile for CPCN approval for the contingent simple cycle unit. On March 28, 2019, Duke Energy Progress filed an annual progress report for the construction of the combined-cycle plants with the NCUC, with an estimated cost of $893 million . Site preparation activities for the combined-cycle plants are complete and construction of these plants began in 2017, with an expected in-service date in late 2019. On October 8, 2018, Duke Energy Progress filed an application with the NCUC for a CPCN to construct the Hot Springs Microgrid Solar and Battery Storage Facility. On March 22, 2019, Duke Energy Progress and the Public Staff filed a Joint Proposed Order. On May 10, 2019, the NCUC issued an Order Granting Certificate of Public Convenience and Necessity with Conditions. The carrying value of the 376 -MW Asheville coal-fired plant, including associated ash basin closure costs, of $234 million and $327 million is included in Generation facilities to be retired, net on Duke Energy Progress' Condensed Consolidated Balance Sheets as of September 30, 2019 , and December 31, 2018 , respectively. Duke Energy Progress' request for a regulatory asset at the time of retirement with amortization over a 10 -year period was approved by the NCUC on February 23, 2018. FERC Return on Equity Complaint On October 11, 2019, North Carolina Eastern Municipal Power Agency (Power Agency) filed a complaint at FERC against Duke Energy Progress pursuant to Section 206 of the Federal Power Act (FPA). The complaint alleges that the return on equity component in the formula rate contained within the Full Requirements Power Purchase Agreement (FRPPA) is unjust and unreasonable. The FRPPA’s return on equity is 11% as applied to the Production Capacity Rate for the full requirements service provided by Duke Energy Progress. The complaint does not definitively propose a replacement return on equity. Under FPA Section 206, the earliest refund effective date that FERC can establish is the date of the filing of the complaint. The complaint could raise risks across the Duke Energy Progress wholesale business because, depending on how FERC treats Power Agency’s complaint, other parties may come forward with similar complaints. Duke Energy Progress cannot predict the outcome of this matter. Duke Energy Florida Storm Restoration Cost Recovery In September 2017, Duke Energy Florida’s service territory suffered significant damage from Hurricane Irma, resulting in approximately 1 million customers experiencing outages. In the fourth quarter of 2017, Duke Energy Florida also incurred preparation costs related to Hurricane Nate. On December 28, 2017, Duke Energy Florida filed a petition with the FPSC to recover incremental storm restoration costs for Hurricane Irma and Hurricane Nate and to replenish the storm reserve. On February 6, 2018, the FPSC approved a stipulation that would apply tax savings resulting from the Tax Act toward storm costs effective January 2018 in lieu of implementing a storm surcharge. On May 31, 2018, Duke Energy Florida filed a petition for approval of actual storm restoration costs and associated recovery process related to Hurricane Irma and Hurricane Nate. The petition sought the approval for the recovery in the amount of $510 million in actual recoverable storm restoration costs, including the replenishment of Duke Energy Florida’s storm reserve of $132 million , and the process for recovering these recoverable storm costs. On August 20, 2018, the FPSC approved Duke Energy Florida's unopposed Motion for Continuance filed August 17, 2018, to allow for an evidentiary hearing in this matter. On January 28, 2019, Duke Energy Florida made a supplemental filing to reduce the total storm cost recovery from $510 million to $508 million . On April 3, 2019, the FPSC issued an Order abating all remaining filing dates. On April 9, 2019, Duke Energy Florida filed an unopposed motion to approve a settlement agreement resolving all outstanding issues in this docket. On June 13, 2019, the FPSC issued its order ap

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES ENVIRONMENTAL The Duke Energy Registrants are subject to federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal, coal ash and other environmental matters. These regulations can be changed from time to time, imposing new obligations on the Duke Energy Registrants. The following environmental matters impact all Duke Energy Registrants. Remediation Activities In addition to AROs recorded as a result of various environmental regulations, 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 on the Condensed 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 Condensed Consolidated Balance Sheets. Nine Months Ended September 30, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 77 $ 11 $ 11 $ 4 $ 6 $ 48 $ 5 $ 2 Provisions/adjustments 30 4 9 3 5 10 — 6 Cash reductions (35 ) (4 ) (3 ) (2 ) (1 ) (28 ) — — Balance at end of period $ 72 $ 11 $ 17 $ 5 $ 10 $ 30 $ 5 $ 8 Nine Months Ended September 30, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 81 $ 10 $ 15 $ 3 $ 12 $ 47 $ 5 $ 2 Provisions/adjustments 7 3 2 3 (1 ) 3 1 — Cash reductions (20 ) (2 ) (5 ) (1 ) (4 ) (12 ) (1 ) — Balance at end of period $ 68 $ 11 $ 12 $ 5 $ 7 $ 38 $ 5 $ 2 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 $ 49 Duke Energy Carolinas 11 Duke Energy Ohio 31 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 and Duke Energy expected to close those sites through a combination of a cap system and a groundwater monitoring system. However, 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 June 14, 2019, NCDEQ filed a motion to dismiss several claims in Duke Energy Carolinas' and Duke Energy Progress' appeals. On August 2, 2019, the court entered an order granting NCDEQ's motion to dismiss several of the claims. Duke Energy has filed a petition with the North Carolina Superior Court seeking review of this order. The lawsuit will proceed on the remaining issues, including whether the NCDEQ's decision was arbitrary and capricious. On September 24, 2019, NCDEQ filed a Motion for Partial Summary Judgment on the issue of whether Duke Energy had notice that NCDEQ was going to make a closure determination on April 1, 2019. On October 28, 2019, the court entered an order granting NCDEQ’s Partial Motion for Summary Judgment. Duke Energy has until November 27, 2019 to file an appeal of that decision. The trial is expected to occur in June 2020. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. Coal Ash Insurance Coverage Litigation In March 2017, Duke Energy Carolinas and Duke Energy Progress filed a civil action in 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. On May 14, 2019, the court granted an extension of stay, until September 15, 2019, to allow the parties to discuss potential resolution. As no resolution was reached, litigation has resumed with fact discovery. The trial is now 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, the 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 of their 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 their remaining 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 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 and the matter is proceeding before the trial court. The court decided to stay any activity in the case and has been holding periodic status conferences while NCDEQ works through the Coal Ash Act process and the ongoing appeal of the April 1 closure decision. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. Federal Citizens Suits On June 13, 2016, the 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 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. The court has not yet ruled on these motions. 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, and the court has not yet ruled on these motions. 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 and shall remain stayed pending further order from the court. 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 and shall remain stayed pending further order from the court. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of these matters. 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 September 30, 2019 , there were 121 asserted claims for non-malignant cases with cumulative relief sought of up to $32 million , and 40 asserted claims for malignant cases with cumulative relief sought of up to $13 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 $592 million at September 30, 2019 , and $630 million at December 31, 2018 . These reserves are classified in Other within Other Noncurrent Liabilities and Other within Current Liabilities on the Condensed Consolidated Balance Sheets. These reserves are based upon Duke Energy Carolinas' best estimate for current and future asbestos claims through 2038 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 2038 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-insured 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 $722 million at September 30, 2019 , and $739 million at December 31, 2018 . These amounts are classified in Other within Other Noncurrent Assets and Receivables within Current Assets on the Condensed 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 2020. 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 combined-cycle natural gas plant in Citrus County, Florida. Fluor filed an amended complaint on February 13, 2019. Fluor’s multicount complaint sought 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 $25 million reduction to a prior-year impairment within Impairment charges on Duke Energy's Condensed Consolidated Statements of Operations in the third quarter of 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 discussed above. Reserves are classified on the Condensed 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. (in millions) September 30, 2019 December 31, 2018 Reserves for Legal Matters Duke Energy $ 62 $ 65 Duke Energy Carolinas 8 9 Progress Energy 52 54 Duke Energy Progress 13 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 Condensed Consolidated Balance Sheets and have unlimited maximum potential payments. However, the Duke Energy Registrants do not believe these guarantees will have a material effect on their results of operations, cash flows or financial position. In addition, the Duke Energy Registrants enter into various fixed-price, noncancelable commitments to purchase or sell power or natural gas, take-or-pay arrangements, transportation, or throughput agreements and other contracts that may or may not be recognized on their respective Condensed Consolidated Balance Sheets. Some of these arrangements may be recognized at fair value on their respective Condensed Consolidated Balance Sheets if such contracts meet the definition of a derivative and the NPNS exception does not apply. In most cases, the Duke Energy Registrants’ purchase obligation contracts contain provisions for price adjustments, minimum purchase levels and other financial commitments.

Leases

Leases	9 Months Ended
	Sep. 30, 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 Condensed 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 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 Condensed 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 $69 million and $205 million for the three and nine months ended September 30, 2019 , respectively. As of September 30, 2019 , renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,347 million and accumulated depreciation of $692 million . These assets are principally classified as nonregulated electric generation and transmission assets. The following tables present the components of lease expense. Three Months Ended September 30, 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) $ 75 $ 13 $ 39 $ 16 $ 23 $ 3 $ 5 $ 1 Short-term lease expense (a) 2 — — — — — 1 — Variable lease expense (a) 27 6 22 21 1 — — — Finance lease expense Amortization of leased assets (b) 28 2 9 1 8 — — — Interest on lease liabilities (c) 7 3 12 10 2 — — — Total finance lease expense 35 5 21 11 10 — — — Total lease expense $ 139 $ 24 $ 82 $ 48 $ 34 $ 3 $ 6 $ 1 Nine Months Ended September 30, 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) $ 220 $ 36 $ 121 $ 52 $ 69 $ 9 $ 15 $ 4 Short-term lease expense (a) 15 4 7 3 4 1 2 — Variable lease expense (a) 48 18 29 24 5 — — — Finance lease expense Amortization of leased assets (b) 84 4 17 3 14 1 — — Interest on lease liabilities (c) 44 10 31 24 7 — 1 — Total finance lease expense 128 14 48 27 21 1 1 — Total lease expense $ 411 $ 72 $ 205 $ 106 $ 99 $ 11 $ 18 $ 4 (a) Included in Operations, maintenance and other or, for barges and railcars, Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations. (b) Included in Depreciation and amortization on the Condensed Consolidated Statements of Operations. (c) Included in Interest Expense on the Condensed Consolidated Statements of Operations. The following table presents rental expense for operating leases, as reported under the old lease standard. These amounts are included in Operation, maintenance and other and Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations. (in millions) Year Ended December 31, 2018 Duke Energy $ 268 Duke Energy Carolinas 49 Progress Energy 143 Duke Energy Progress 75 Duke Energy Florida 68 Duke Energy Ohio 13 Duke Energy Indiana 21 Piedmont 11 The following table presents operating lease maturities and a reconciliation of the undiscounted cash flows to operating lease liabilities. Twelve Months Ended September 30, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 278 $ 32 $ 129 $ 51 $ 78 $ 2 $ 6 $ 5 2021 220 20 100 45 55 2 4 5 2022 201 19 95 40 55 2 4 5 2023 192 18 95 41 54 2 4 5 2024 179 14 95 41 54 2 4 5 Thereafter 1,008 60 480 291 189 22 63 6 Total operating lease payments 2,078 163 994 509 485 32 85 31 Less: present value discount (410 ) (28 ) (185 ) (113 ) (72 ) (10 ) (27 ) (3 ) Total operating lease liabilities (a) $ 1,668 $ 135 $ 809 $ 396 $ 413 $ 22 $ 58 $ 28 (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 old 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. Twelve Months Ended September 30, Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana 2020 $ 179 $ 19 $ 69 $ 44 $ 25 $ 1 2021 184 16 69 44 25 1 2022 177 14 69 44 25 1 2023 173 14 69 44 25 1 2024 149 14 57 44 13 1 Thereafter 827 189 552 539 13 27 Total finance lease payments 1,689 266 885 759 126 32 Less: amounts representing interest (699 ) (160 ) (477 ) (451 ) (26 ) (22 ) Total finance lease liabilities $ 990 $ 106 $ 408 $ 308 $ 100 $ 10 The following table presents future minimum lease payments under finance leases, as reported under the old 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. September 30, 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 $ 1,703 $ 135 $ 814 $ 397 $ 417 $ 22 $ 58 $ 25 Finance Net property, plant and equipment 952 125 448 309 139 — 10 — Total lease assets $ 2,655 $ 260 $ 1,262 $ 706 $ 556 $ 22 $ 68 $ 25 Liabilities Current Operating Other current liabilities $ 212 $ 27 $ 99 $ 36 $ 63 $ 1 $ 3 $ 4 Finance Current maturities of long-term debt 117 6 23 6 17 — — — Noncurrent Operating Operating lease liabilities 1,456 108 710 360 350 21 55 24 Finance Long-Term Debt 873 100 385 302 83 — 10 — Total lease liabilities $ 2,658 $ 241 $ 1,217 $ 704 $ 513 $ 22 $ 68 $ 28 Nine Months Ended September 30, 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 $ 221 $ 26 $ 104 $ 43 $ 61 $ 1 $ 5 $ 6 Operating cash flows from finance leases 44 10 31 24 7 — 1 — Financing cash flows from finance leases 84 4 17 3 14 1 — — Lease assets obtained in exchange for new lease liabilities (non-cash) Operating (b) $ 147 $ 44 $ 30 $ 30 $ — $ — $ — $ 1 Finance 175 — 175 175 — — — — (a) No amounts were classified as investing cash flows from operating leases for the nine months ended September 30, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. September 30, 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 18 18 6 Finance leases 13 18 16 18 11 — 27 — Weighted-average discount rate (a) Operating leases 3.9 % 3.5 % 3.8 % 3.9 % 3.8 % 4.3 % 4.1 % 3.6 % Finance leases 8.0 % 12.9 % 11.8 % 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 Condensed 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 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 Condensed 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 $69 million and $205 million for the three and nine months ended September 30, 2019 , respectively. As of September 30, 2019 , renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,347 million and accumulated depreciation of $692 million . These assets are principally classified as nonregulated electric generation and transmission assets. The following tables present the components of lease expense. Three Months Ended September 30, 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) $ 75 $ 13 $ 39 $ 16 $ 23 $ 3 $ 5 $ 1 Short-term lease expense (a) 2 — — — — — 1 — Variable lease expense (a) 27 6 22 21 1 — — — Finance lease expense Amortization of leased assets (b) 28 2 9 1 8 — — — Interest on lease liabilities (c) 7 3 12 10 2 — — — Total finance lease expense 35 5 21 11 10 — — — Total lease expense $ 139 $ 24 $ 82 $ 48 $ 34 $ 3 $ 6 $ 1 Nine Months Ended September 30, 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) $ 220 $ 36 $ 121 $ 52 $ 69 $ 9 $ 15 $ 4 Short-term lease expense (a) 15 4 7 3 4 1 2 — Variable lease expense (a) 48 18 29 24 5 — — — Finance lease expense Amortization of leased assets (b) 84 4 17 3 14 1 — — Interest on lease liabilities (c) 44 10 31 24 7 — 1 — Total finance lease expense 128 14 48 27 21 1 1 — Total lease expense $ 411 $ 72 $ 205 $ 106 $ 99 $ 11 $ 18 $ 4 (a) Included in Operations, maintenance and other or, for barges and railcars, Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations. (b) Included in Depreciation and amortization on the Condensed Consolidated Statements of Operations. (c) Included in Interest Expense on the Condensed Consolidated Statements of Operations. The following table presents rental expense for operating leases, as reported under the old lease standard. These amounts are included in Operation, maintenance and other and Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations. (in millions) Year Ended December 31, 2018 Duke Energy $ 268 Duke Energy Carolinas 49 Progress Energy 143 Duke Energy Progress 75 Duke Energy Florida 68 Duke Energy Ohio 13 Duke Energy Indiana 21 Piedmont 11 The following table presents operating lease maturities and a reconciliation of the undiscounted cash flows to operating lease liabilities. Twelve Months Ended September 30, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 278 $ 32 $ 129 $ 51 $ 78 $ 2 $ 6 $ 5 2021 220 20 100 45 55 2 4 5 2022 201 19 95 40 55 2 4 5 2023 192 18 95 41 54 2 4 5 2024 179 14 95 41 54 2 4 5 Thereafter 1,008 60 480 291 189 22 63 6 Total operating lease payments 2,078 163 994 509 485 32 85 31 Less: present value discount (410 ) (28 ) (185 ) (113 ) (72 ) (10 ) (27 ) (3 ) Total operating lease liabilities (a) $ 1,668 $ 135 $ 809 $ 396 $ 413 $ 22 $ 58 $ 28 (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 old 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. Twelve Months Ended September 30, Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana 2020 $ 179 $ 19 $ 69 $ 44 $ 25 $ 1 2021 184 16 69 44 25 1 2022 177 14 69 44 25 1 2023 173 14 69 44 25 1 2024 149 14 57 44 13 1 Thereafter 827 189 552 539 13 27 Total finance lease payments 1,689 266 885 759 126 32 Less: amounts representing interest (699 ) (160 ) (477 ) (451 ) (26 ) (22 ) Total finance lease liabilities $ 990 $ 106 $ 408 $ 308 $ 100 $ 10 The following table presents future minimum lease payments under finance leases, as reported under the old 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. September 30, 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 $ 1,703 $ 135 $ 814 $ 397 $ 417 $ 22 $ 58 $ 25 Finance Net property, plant and equipment 952 125 448 309 139 — 10 — Total lease assets $ 2,655 $ 260 $ 1,262 $ 706 $ 556 $ 22 $ 68 $ 25 Liabilities Current Operating Other current liabilities $ 212 $ 27 $ 99 $ 36 $ 63 $ 1 $ 3 $ 4 Finance Current maturities of long-term debt 117 6 23 6 17 — — — Noncurrent Operating Operating lease liabilities 1,456 108 710 360 350 21 55 24 Finance Long-Term Debt 873 100 385 302 83 — 10 — Total lease liabilities $ 2,658 $ 241 $ 1,217 $ 704 $ 513 $ 22 $ 68 $ 28 Nine Months Ended September 30, 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 $ 221 $ 26 $ 104 $ 43 $ 61 $ 1 $ 5 $ 6 Operating cash flows from finance leases 44 10 31 24 7 — 1 — Financing cash flows from finance leases 84 4 17 3 14 1 — — Lease assets obtained in exchange for new lease liabilities (non-cash) Operating (b) $ 147 $ 44 $ 30 $ 30 $ — $ — $ — $ 1 Finance 175 — 175 175 — — — — (a) No amounts were classified as investing cash flows from operating leases for the nine months ended September 30, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. September 30, 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 18 18 6 Finance leases 13 18 16 18 11 — 27 — Weighted-average discount rate (a) Operating leases 3.9 % 3.5 % 3.8 % 3.9 % 3.8 % 4.3 % 4.1 % 3.6 % Finance leases 8.0 % 12.9 % 11.8 % 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	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt And Credit Facilities	DEBT AND CREDIT FACILITIES SUMMARY OF SIGNIFICANT DEBT ISSUANCES The following table summarizes significant debt issuances (in millions). Nine Months Ended September 30, 2019 Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Ohio Indiana Piedmont Unsecured Debt March 2019 (a) March 2022 2.788 % (b) $ 300 $ 300 $ — $ — $ — $ — $ — March 2019 (a) March 2022 3.227 % 300 300 — — — — — May 2019 (e) June 2029 3.500 % 600 — — — — — 600 June 2019 (a) June 2029 3.400 % 600 600 — — — — — June 2019 (a) June 2049 4.200 % 600 600 — — — — — July 2019 (g) July 2049 4.320 % 40 — — — 40 — — September 2019 (g) October 2025 3.230 % 95 — — — 95 — — September 2019 (g) October 2029 3.560 % 75 — — — 75 — — First Mortgage Bonds January 2019 (c) February 2029 3.650 % 400 — — — 400 — — January 2019 (c) February 2049 4.300 % 400 — — — 400 — — March 2019 (d) March 2029 3.450 % 600 — — 600 — — — August 2019 (a) August 2029 2.450 % 450 — 450 — — — — August 2019 (a) August 2049 3.200 % 350 — 350 — — — — September 2019 (f) October 2049 3.250 % 500 — — — — 500 — Total issuances $ 5,310 $ 1,800 $ 800 $ 600 $ 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. CURRENT MATURITIES OF LONG-TERM DEBT The following table shows the significant components of Current Maturities of Long-Term Debt on the Condensed 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 September 30, 2019 Unsecured Debt Duke Energy Kentucky October 2019 4.650 % $ 100 Progress Energy December 2019 4.875 % 350 Duke Energy (Parent) June 2020 2.100 % 330 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 2.282 % (a) 300 Other (b) 566 Current maturities of long-term debt $ 3,096 (a) Debt issuance has a floating interest rate. (b) Includes finance lease obligations, amortizing debt and small bullet maturities. AVAILABLE CREDIT FACILITIES Master Credit Facility 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 (Parent), 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 the Master Credit Facility. September 30, 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 $ 1,750 $ 1,250 $ 800 $ 450 $ 600 $ 500 Reduction to backstop issuances Commercial paper (b) (1,971 ) (627 ) (338 ) (211 ) (277 ) (164 ) (150 ) (204 ) Outstanding letters of credit (51 ) (43 ) (4 ) (2 ) — — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity under the Master Credit Facility $ 5,397 $ 1,980 $ 1,158 $ 787 $ 523 $ 286 $ 369 $ 294 (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 on the Condensed Consolidated Balance Sheets. Other Credit Facilities September 30, 2019 (in millions) Facility size Amount drawn Duke Energy (Parent) Three-Year Revolving Credit Facility (a) $ 1,000 $ 500 Duke Energy Progress Term Loan Facility 700 700 (a) In May 2019, Duke Energy (Parent) extended the termination date to May 2022. In May 2019, the $350 million Piedmont term loan was paid off in full with proceeds from the $600 million Piedmont debt offering.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2019
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS The Duke Energy Registrants record AROs when there is a legal obligation to incur retirement costs associated with the retirement of a long-lived asset and the obligation can be reasonably estimated. Actual closure costs incurred could be materially different from current estimates that form the basis of the recorded AROs. The following table presents the AROs recorded on the Condensed Consolidated Balance Sheets. September 30, 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) $ 5,789 $ 2,435 $ 3,295 $ 2,769 $ 526 $ — $ — $ — Closure of ash impoundments 6,486 2,917 2,722 2,707 15 43 804 — Other 326 46 71 38 33 42 20 20 Total ARO $ 12,601 $ 5,398 $ 6,088 $ 5,514 $ 574 $ 85 $ 824 $ 20 Less: current portion 861 214 478 476 2 3 165 — Total noncurrent ARO $ 11,740 $ 5,184 $ 5,610 $ 5,038 $ 572 $ 82 $ 659 $ 20 (a) Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy. ARO Liability Rollforward The following table presents the change in liability associated with AROs for the Duke Energy Registrants. 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 (a) $ 10,467 $ 3,949 $ 5,411 $ 4,820 $ 591 $ 93 $ 722 $ 19 Accretion expense (b) 377 173 190 171 19 3 21 1 Liabilities settled (c) (691 ) (276 ) (375 ) (341 ) (34 ) (9 ) (32 ) — Revisions in estimates of cash flows (d) 2,448 1,552 862 864 (2 ) (2 ) 113 — Balance at September 30, 2019 $ 12,601 $ 5,398 $ 6,088 $ 5,514 $ 574 $ 85 $ 824 $ 20 (a) Primarily relates to decommissioning nuclear power facilities, closure of ash impoundments, asbestos removal, closure of landfills at fossil generation facilities, retirement of natural gas mains and removal of renewable energy generation assets. (b) For the nine months ended September 30, 2019 , substantially all accretion expense relates to Duke Energy's regulated operations and has been deferred in accordance with regulatory accounting treatment. (c) Primarily relates to ash impoundment closures. (d) Primarily relates to increases in closure estimates for certain ash impoundments as a result of the NCDEQ's April 1 Order. See Note 4 for more information. The incremental amount recorded represents the discounted cash flows for estimated closure costs based upon the probability weightings of the potential closure methods as evaluated on a site-by-site basis. Asset retirement costs associated with the AROs for operating plants and retired plants are included in Net property, plant and equipment and Regulatory assets within Other Noncurrent Assets, respectively, on the Condensed Consolidated Balance Sheets. 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 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 12 for additional information related to the fair value of the Duke Energy Registrants' NDTFs. (in millions) September 30, 2019 December 31, 2018 Duke Energy $ 6,403 $ 5,579 Duke Energy Carolinas 3,614 3,133 Duke Energy Progress 2,789 2,446

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL Duke Energy The following table presents the goodwill by reportable segment included on Duke Energy's Condensed Consolidated Balance Sheets at September 30, 2019 , and December 31, 2018 . Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill balance $ 17,379 $ 1,924 $ 122 $ 19,425 Accumulated impairment charges — — (122 ) (122 ) Goodwill, adjusted for accumulated impairment charges $ 17,379 $ 1,924 $ — $ 19,303 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 Condensed Consolidated Balance Sheets at September 30, 2019 , and December 31, 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. 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 the third quarter of 2019.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Subsidiary Registrants engage in related party transactions in accordance with applicable state and federal commission regulations. Refer to the Condensed 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 on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 197 $ 214 $ 606 $ 647 Indemnification coverages (b) 5 6 15 17 JDA revenue (c) 12 13 52 66 JDA expense (c) 32 61 145 134 Intercompany natural gas purchases (d) — 3 7 11 Progress Energy Corporate governance and shared service expenses (a) $ 194 $ 216 $ 553 $ 613 Indemnification coverages (b) 8 8 27 25 JDA revenue (c) 32 61 145 134 JDA expense (c) 12 13 52 66 Intercompany natural gas purchases (d) 19 20 57 58 Duke Energy Progress Corporate governance and shared service expenses (a) $ 114 $ 138 $ 328 $ 382 Indemnification coverages (b) 3 3 11 9 JDA revenue (c) 32 61 145 134 JDA expense (c) 12 13 52 66 Intercompany natural gas purchases (d) 19 20 57 58 Duke Energy Florida Corporate governance and shared service expenses (a) $ 80 $ 78 $ 225 $ 231 Indemnification coverages (b) 5 5 16 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 90 $ 85 $ 258 $ 264 Indemnification coverages (b) 1 1 3 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 109 $ 105 $ 299 $ 302 Indemnification coverages (b) 2 2 5 6 Piedmont Corporate governance and shared service expenses (a) $ 33 $ 39 $ 102 $ 115 Indemnification coverages (b) 1 1 2 2 Intercompany natural gas sales (d) 19 23 64 69 Natural gas storage and transportation costs (e) 6 6 17 18 (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 Condensed 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 Condensed 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 Condensed 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 Condensed Consolidated Statements of Operations and Comprehensive Income. (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 Condensed 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. These transactions of the Subsidiary Registrants are incurred in the ordinary course of business and are eliminated in consolidation. As discussed in Note 13 , 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 September 30, 2019 Intercompany income tax receivable $ — $ 178 $ 60 $ 10 $ 14 $ 3 $ 85 Intercompany income tax payable 71 — — — — — — December 31, 2018 Intercompany income tax receivable $ 52 $ 47 $ 29 $ — $ — $ 8 $ — Intercompany income tax payable — — — 16 3 — 45

Derivatives and Hedging

Derivatives and Hedging	9 Months Ended
	Sep. 30, 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 Condensed Consolidated Balance Sheets. Cash collateral related to derivative instruments executed under master netting arrangements is offset against the collateralized derivatives on the Condensed Consolidated Balance Sheets. The cash impacts of settled derivatives are recorded as operating activities on the Condensed 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 three and nine months ended September 30, 2019 , and 2018 , 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 Condensed Consolidated Statements of Operations and Comprehensive Income. The following table shows notional amounts of outstanding derivatives related to interest rate risk. September 30, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 1,031 $ — $ — $ — $ — $ — Undesignated contracts 1,577 450 1,100 250 850 27 Total notional amount (a) $ 2,608 $ 450 $ 1,100 $ 250 $ 850 $ 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 $ 923 $ — $ — $ — $ — $ — Undesignated contracts 1,721 300 1,200 650 550 27 Total notional amount (a) $ 2,644 $ 300 $ 1,200 $ 650 $ 550 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $731 million in cash flow hedges as of September 30, 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 natural gas costs 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. September 30, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 25,658 — — — — 2,774 22,884 — Natural gas (millions of dekatherms) 729 130 175 175 — — 4 420 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 dekatherms) 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 3 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 September 30, 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 ON THE CONDENSED 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 Condensed 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 September 30, 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 $ 23 $ — $ — $ — $ — $ 5 $ 16 $ 2 Total Derivative Assets – Commodity Contracts $ 23 $ — $ — $ — $ — $ 5 $ 16 $ 2 Interest Rate Contracts Designated as Hedging Instruments Current $ 3 $ — $ — $ — $ — $ — $ — $ — Total Derivative Assets – Interest Rate Contracts $ 3 $ — $ — $ — $ — $ — $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 5 — 5 — 5 — — — Total Derivative Assets – Equity Securities Contracts $ 5 $ — $ 5 $ — $ 5 $ — $ — $ — Total Derivative Assets $ 31 $ — $ 5 $ — $ 5 $ 5 $ 16 $ 2 Derivative Liabilities September 30, 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 $ 66 $ 33 $ 24 $ 24 $ — $ — $ — $ 9 Noncurrent 147 12 34 18 — — — 102 Total Derivative Liabilities – Commodity Contracts $ 213 $ 45 $ 58 $ 42 $ — $ — $ — $ 111 Interest Rate Contracts Designated as Hedging Instruments Current $ 2 $ — $ — $ — $ — $ — $ — $ — Noncurrent 56 — — — — — — — Not Designated as Hedging Instruments Current 64 22 42 1 41 1 — — Noncurrent 8 — 3 — 3 5 — — Total Derivative Liabilities – Interest Rate Contracts $ 130 $ 22 $ 45 $ 1 $ 44 $ 6 $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 10 — 10 — 10 — — — Total Derivative Liabilities – Equity Securities Contracts $ 10 $ — $ 10 $ — $ 10 $ — $ — $ — Total Derivative Liabilities $ 353 $ 67 $ 113 $ 43 $ 54 $ 6 $ — $ 111 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 Condensed 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 September 30, 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 $ 31 $ — $ 5 $ — $ 5 $ 5 $ 16 $ 2 Gross amounts offset (5 ) — (5 ) — (5 ) — — — Net amounts presented in Current Assets: Other $ 26 $ — $ — $ — $ — $ 5 $ 16 $ 2 Derivative Liabilities September 30, 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 $ 142 $ 55 $ 76 $ 25 $ 51 $ 1 $ — $ 9 Gross amounts offset (10 ) — (10 ) — (10 ) — — — Net amounts presented in Current Liabilities: Other $ 132 $ 55 $ 66 $ 25 $ 41 $ 1 $ — $ 9 Noncurrent Gross amounts recognized $ 211 $ 12 $ 37 $ 18 $ 3 $ 5 $ — $ 102 Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 211 $ 12 $ 37 $ 18 $ 3 $ 5 $ — $ 102 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. September 30, 2019 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 82 $ 40 $ 42 $ 42 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 82 40 42 42 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	9 Months Ended
	Sep. 30, 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 through 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 September 30, 2019 , and December 31, 2018 . Other Investments amounts are recorded in Other within Other Noncurrent Assets on the Condensed 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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 114 $ — $ — $ 88 Equity securities 3,118 63 5,222 2,402 95 4,475 Corporate debt securities 40 1 633 4 13 566 Municipal bonds 14 — 370 1 4 353 U.S. government bonds 39 — 1,217 14 12 1,076 Other debt securities 4 — 142 — 2 148 Total NDTF Investments $ 3,215 $ 64 $ 7,698 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 53 $ — $ — $ 22 Equity securities 48 — 112 36 1 99 Corporate debt securities 2 — 72 — 2 60 Municipal bonds 5 — 94 — 1 85 U.S. government bonds 3 — 40 1 — 45 Other debt securities 1 — 65 — 1 58 Total Other Investments $ 59 $ — $ 436 $ 37 $ 5 $ 369 Total Investments $ 3,274 $ 64 $ 8,134 $ 2,458 $ 131 $ 7,075 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 60 $ 19 $ 161 $ 85 Realized losses 43 16 136 60 AFS: Realized gains 53 4 110 14 Realized losses 36 7 83 32 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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 36 $ — $ — $ 29 Equity securities 1,680 15 2,901 1,309 54 2,484 Corporate debt securities 24 1 409 2 9 341 Municipal bonds 4 — 96 — 1 81 U.S. government bonds 19 — 517 5 8 475 Other debt securities 4 — 137 — 2 143 Total NDTF Investments $ 1,731 $ 16 $ 4,096 $ 1,316 $ 74 $ 3,553 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 34 $ 11 $ 101 $ 47 Realized losses 26 8 95 30 AFS: Realized gains 21 4 46 13 Realized losses 13 6 34 24 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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 78 $ — $ — $ 59 Equity securities 1,438 48 2,321 1,093 41 1,991 Corporate debt securities 16 — 224 2 4 225 Municipal bonds 10 — 274 1 3 272 U.S. government bonds 20 — 700 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,484 $ 48 $ 3,602 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 49 $ — $ — $ 17 Municipal bonds 4 — 52 — — 47 Total Other Investments $ 4 $ — $ 101 $ — $ — $ 64 Total Investments $ 1,488 $ 48 $ 3,703 $ 1,105 $ 52 $ 3,217 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 26 $ 8 $ 60 $ 38 Realized losses 17 8 41 30 AFS: Realized gains 31 — 62 1 Realized losses 23 1 49 8 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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 46 Equity securities 1,107 30 1,907 833 30 1,588 Corporate debt securities 16 — 224 2 3 171 Municipal bonds 10 — 274 1 3 271 U.S. government bonds 19 — 420 6 3 415 Other debt securities — — 5 — — 3 Total NDTF Investments $ 1,152 $ 30 $ 2,882 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Total Other Investments $ — $ — $ 2 $ — $ — $ 6 Total Investments $ 1,152 $ 30 $ 2,884 $ 842 $ 39 $ 2,500 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 10 $ 7 $ 27 $ 32 Realized losses 9 7 24 27 AFS: Realized gains 2 — 4 1 Realized losses — 1 2 6 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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 26 $ — $ — $ 13 Equity securities 331 18 414 260 11 403 Corporate debt securities — — — — 1 54 Municipal bonds — — — — — 1 U.S. government bonds 1 — 280 3 1 186 Other debt securities — — — — — 2 Total NDTF Investments (a) $ 332 $ 18 $ 720 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 1 Municipal bonds 4 — 52 — — 47 Total Other Investments $ 4 $ — $ 56 $ — $ — $ 48 Total Investments $ 336 $ 18 $ 776 $ 263 $ 13 $ 707 (a) During the nine months ended September 30, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of Crystal River Unit 3. Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 16 $ 1 $ 33 $ 6 Realized losses 8 1 17 3 AFS: Realized gains 29 — 58 — Realized losses 23 — 47 2 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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value Investments Equity securities $ 37 $ — $ 74 $ 29 $ — $ 67 Corporate debt securities — — 6 — — 8 Municipal bonds 1 — 36 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 38 $ — $ 117 $ 29 $ 1 $ 108 Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2019 , and 2018, were insignificant. DEBT SECURITY MATURITIES The table below summarizes the maturity date for debt securities. September 30, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Due in one year or less $ 400 $ 65 $ 328 $ 48 $ 280 $ 4 Due after one through five years 524 220 253 243 10 15 Due after five through 10 years 450 187 209 201 8 5 Due after 10 years 1,259 687 465 431 34 19 Total $ 2,633 $ 1,159 $ 1,255 $ 923 $ 332 $ 43

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 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 NAV 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. Transfers between levels represent assets or liabilities that were previously (i) categorized at a higher level for which the inputs to the estimate became less observable or (ii) classified at a lower level for which the inputs became more observable during the period. The Duke Energy Registrant’s policy is to recognize transfers between levels of the fair value hierarchy at the end of the period. There were no transfers between levels during the nine months ended September 30, 2019 , and 2018 . 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 New York Stock Exchange 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. Other commodity derivatives, including Piedmont's natural gas supply contracts, are primarily valued using internally developed discounted cash flow models that incorporate forward price, adjustments for liquidity (bid-ask spread) and credit or non-performance risk (after reflecting credit enhancements such as collateral), and are discounted to present value. Pricing inputs are derived from published exchange transaction prices and other observable data sources. In the absence of an active market, the last available price may be used. 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 11 in Duke Energy's Annual Report on Form 10-K for the year ended December 31, 2018, 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 Condensed Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type for the Duke Energy Registrants. September 30, 2019 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 5,222 $ 5,168 $ — $ — $ 54 NDTF debt securities 2,476 804 1,672 — — Other equity securities 112 112 — — — Other debt securities 324 92 232 — — Derivative assets 31 2 8 21 — Total assets 8,165 6,178 1,912 21 54 Derivative liabilities (353 ) (25 ) (217 ) (111 ) — Net assets (liabilities) $ 7,812 $ 6,153 $ 1,695 $ (90 ) $ 54 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 tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ (79 ) $ (97 ) $ (113 ) $ (114 ) Purchases, sales, issuances and settlements: Purchases — — 38 56 Settlements (9 ) (14 ) (32 ) (43 ) Total (losses) gains included on the Condensed Consolidated Balance Sheet (2 ) (5 ) 17 (15 ) Balance at end of period $ (90 ) $ (116 ) $ (90 ) $ (116 ) DUKE ENERGY CAROLINAS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. September 30, 2019 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 2,901 $ 2,847 $ — $ 54 NDTF debt securities 1,195 189 1,006 — Total assets 4,096 3,036 1,006 54 Derivative liabilities (67 ) — (67 ) — Net assets $ 4,029 $ 3,036 $ 939 $ 54 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 tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,321 $ 2,321 $ — $ 1,991 $ 1,991 $ — NDTF debt securities 1,281 615 666 1,162 427 735 Other debt securities 101 49 52 64 17 47 Derivative assets 5 — 5 4 — 4 Total assets 3,708 2,985 723 3,221 2,435 786 Derivative liabilities (113 ) — (113 ) (44 ) — (44 ) Net assets $ 3,595 $ 2,985 $ 610 $ 3,177 $ 2,435 $ 742 DUKE ENERGY PROGRESS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,907 $ 1,907 $ — $ 1,588 $ 1,588 $ — NDTF debt securities 975 309 666 906 294 612 Other debt securities 2 2 — 6 6 — Derivative assets — — — 4 — 4 Total assets 2,884 2,218 666 2,504 1,888 616 Derivative liabilities (43 ) — (43 ) (27 ) — (27 ) Net assets $ 2,841 $ 2,218 $ 623 $ 2,477 $ 1,888 $ 589 DUKE ENERGY FLORIDA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 414 $ 414 $ — $ 403 $ 403 $ — NDTF debt securities 306 306 — 256 133 123 Other debt securities 56 4 52 48 1 47 Derivative assets 5 — 5 — — — Total assets 781 724 57 707 537 170 Derivative liabilities (54 ) — (54 ) (9 ) — (9 ) Net assets $ 727 $ 724 $ 3 $ 698 $ 537 $ 161 DUKE ENERGY OHIO The recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets were not material at September 30, 2019 , and December 31, 2018 . DUKE ENERGY INDIANA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. September 30, 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 $ 74 $ 74 $ — $ — $ 67 $ 67 $ — $ — Other debt securities 43 — 43 — 41 — 41 — Derivative assets 16 — — 16 23 1 — 22 Total assets $ 133 $ 74 $ 43 $ 16 $ 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) Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ 28 $ 44 $ 22 $ 27 Purchases, sales, issuances and settlements: Purchases — — 29 49 Settlements (7 ) (13 ) (26 ) (41 ) Total losses included on the Condensed Consolidated Balance Sheet (5 ) (2 ) (9 ) (6 ) Balance at end of period $ 16 $ 29 $ 16 $ 29 PIEDMONT The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 3 Total Fair Value Level 1 Level 3 Derivative assets $ 2 $ 2 $ — $ 3 $ 3 $ — Derivative liabilities (111 ) — (111 ) (141 ) — (141 ) Net (liabilities) assets $ (109 ) $ 2 $ (111 ) $ (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) Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ (114 ) $ (150 ) $ (141 ) $ (142 ) Total gains (losses) and settlements 3 (3 ) 30 (11 ) Balance at end of period $ (111 ) $ (153 ) $ (111 ) $ (153 ) QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. September 30, 2019 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 5 RTO auction pricing FTR price – per MWh $ 0.57 - $ 3.38 Duke Energy Indiana FTRs 16 RTO auction pricing FTR price – per MWh (0.52 ) - 6.85 Piedmont Natural gas contracts (111 ) Discounted cash flow Forward natural gas curves – price per MMBtu 1.85 - 2.99 Duke Energy Total Level 3 derivatives $ (90 ) 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. September 30, 2019 December 31, 2018 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy (a) $ 57,914 $ 63,276 $ 54,529 $ 54,534 Duke Energy Carolinas 11,758 13,462 10,939 11,471 Progress Energy 19,119 21,952 18,911 19,885 Duke Energy Progress 9,049 9,995 8,204 8,300 Duke Energy Florida 7,132 8,356 7,321 7,742 Duke Energy Ohio 2,719 3,096 2,165 2,239 Duke Energy Indiana 4,208 5,018 3,782 4,158 Piedmont 2,384 2,664 2,138 2,180 (a) Book value of long-term debt includes $1.5 billion as of September 30, 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 September 30, 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	9 Months Ended
	Sep. 30, 2019
Variable Interest Entities [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES 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 nine months ended September 30, 2019 , and the year ended December 31, 2018 , 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 limited liability companies 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 Condensed 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 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 Condensed 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 are not performed 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 December 2020 December 2020 February 2021 April 2021 Credit facility amount $ 350 $ 475 $ 325 $ 250 Amounts borrowed at September 30, 2019 350 475 325 250 Amounts borrowed at December 31, 2018 325 450 300 225 Restricted Receivables at September 30, 2019 505 775 564 471 Restricted Receivables at December 31, 2018 564 699 547 357 Nuclear Asset-Recovery Bonds – 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 June 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 Condensed Consolidated Balance Sheets. (in millions) September 30, 2019 December 31, 2018 Receivables of VIEs $ 7 $ 5 Regulatory Assets: Current 52 52 Current Assets: Other 16 39 Other Noncurrent Assets: Regulatory assets 1,002 1,041 Current Liabilities: Other 2 10 Current maturities of long-term debt 54 53 Long-Term Debt 1,056 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 solar energy systems 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 Condensed Consolidated Balance Sheets related to Commercial Renewables VIEs. (in millions) September 30, 2019 December 31, 2018 Current Assets: Other $ 172 $ 123 Property, Plant and Equipment: Cost 5,160 4,007 Accumulated depreciation and amortization (996 ) (698 ) Other Noncurrent Assets: Other 63 261 Current maturities of long-term debt 177 174 Long-Term Debt 1,604 1,587 Other Noncurrent Liabilities: Asset retirement obligations 125 106 Other Noncurrent Liabilities: Other 218 212 NON-CONSOLIDATED VIEs The following tables summarize the impact of non-consolidated VIEs on the Condensed Consolidated Balance Sheets. September 30, 2019 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 48 $ 76 Investments in equity method unconsolidated affiliates 1,152 235 55 1,442 — — Total assets $ 1,152 $ 235 $ 55 $ 1,442 $ 48 $ 76 Taxes accrued (2 ) — — (2 ) — — Other current liabilities — — 3 3 — — Deferred income taxes 57 — — 57 — — Other noncurrent liabilities — — 11 11 — — Total liabilities $ 55 $ — $ 14 $ 69 $ — $ — Net assets $ 1,097 $ 235 $ 41 $ 1,373 $ 48 $ 76 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 $802 million , which represents 47% of the outstanding borrowings under the credit facility as of September 30, 2019 . For more information on various guarantees, refer to Note 4 . 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 September 30, December 31, Entity Name Interest 2019 2018 ACP (a) 47 % $ 1,127 $ 797 Constitution 24 % 25 25 Total $ 1,152 $ 822 (a) Duke Energy evaluated this investment for impairment as of September 30, 2019 , and December 31, 2018 , and determined that fair value approximated carrying value and therefore no impairment was necessary. 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. Pioneer Duke Energy holds a 50% equity interest in Pioneer. During the nine months ended September 30, 2019, Pioneer was considered a VIE due to having insufficient equity to finance its own activities without subordinated financial support. On October 1, 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 $55 million at September 30, 2019. 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 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 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. 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. The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 Receivables sold $ 217 $ 269 $ 326 $ 336 Less: Retained interests 48 93 76 118 Net receivables sold $ 169 $ 176 $ 250 $ 218 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, (in millions) 2019 2018 2019 2018 2019 2018 2019 2018 Sales Receivables sold $ 479 $ 450 $ 1,483 $ 1,478 $ 762 $ 754 $ 2,172 $ 2,140 Loss recognized on sale 4 4 11 10 4 5 13 12 Cash flows Cash proceeds from receivables sold $ 471 $ 449 $ 1,516 $ 1,499 $ 762 $ 743 $ 2,200 $ 2,140 Collection fees received — — 1 1 — — 1 1 Return received on retained interests 1 2 5 5 2 3 7 7 Cash flows from sales of receivables are reflected within Operating Activities on Duke Energy Ohio’s and Duke Energy Indiana’s Condensed Consolidated Statements of Cash Flows.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE 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. 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) 2019 2020 2021 2022 2023 Thereafter Total Progress Energy $ 31 $ 121 $ 86 $ 81 $ 38 $ 41 $ 398 Duke Energy Progress 2 8 8 8 8 8 42 Duke Energy Florida 29 113 78 73 30 33 356 Duke Energy Indiana 2 10 5 — — — 17 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 revenues 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. 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) 2019 2020 2021 2022 2023 Thereafter Total Piedmont $ 17 $ 69 $ 64 $ 64 $ 61 $ 430 $ 705 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. Other The remainder of Duke Energy’s operations is presented as Other, which does not include material revenues from contracts with customers. Disaggregated Revenues Disaggregated revenues are presented as follows: Three Months Ended September 30, 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 $ 2,923 $ 892 $ 1,522 $ 625 $ 897 $ 215 $ 294 $ — General 1,885 687 843 399 444 127 225 — Industrial 869 372 255 189 66 40 204 — Wholesale 617 113 429 368 61 13 63 — Other revenues 198 76 118 70 48 18 22 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 6,492 $ 2,140 $ 3,167 $ 1,651 $ 1,516 $ 413 $ 808 $ — Gas Utilities and Infrastructure Residential $ 113 $ — $ — $ — $ — $ 53 $ — $ 59 Commercial 68 — — — — 21 — 47 Industrial 26 — — — — 4 — 25 Power Generation — — — — — — — 13 Other revenues 16 — — — — 3 — 13 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 223 $ — $ — $ — $ — $ 81 $ — $ 157 Commercial Renewables Revenue from contracts with customers $ 69 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 8 $ — $ — $ — $ — $ — $ — $ — Total revenue from contracts with customers $ 6,792 $ 2,140 $ 3,167 $ 1,651 $ 1,516 $ 494 $ 808 $ 157 Other revenue sources (a) $ 148 $ 22 $ 75 $ 37 $ 32 $ (5 ) $ (1 ) $ 11 Total revenues $ 6,940 $ 2,162 $ 3,242 $ 1,688 $ 1,548 $ 489 $ 807 $ 168 (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. Three Months Ended September 30, 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 $ 2,729 $ 823 $ 1,425 $ 572 $ 853 $ 203 $ 279 $ — General 1,763 635 800 373 427 112 218 — Industrial 835 352 246 177 69 33 202 — Wholesale 589 132 372 335 37 3 81 — Other revenues 225 109 134 90 44 20 29 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 6,141 $ 2,051 $ 2,977 $ 1,547 $ 1,430 $ 371 $ 809 $ — Gas Utilities and Infrastructure Residential $ 116 $ — $ — $ — $ — $ 59 $ — $ 57 Commercial 66 — — — — 20 — 46 Industrial 28 — — — — 3 — 24 Power Generation — — — — — — — 13 Other revenues 23 — — — — 1 — 22 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 233 $ — $ — $ — $ — $ 83 $ — $ 162 Commercial Renewables Revenue from contracts with customers $ 61 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 16 $ — $ — $ — $ — $ 12 $ — $ — Total revenue from contracts with customers $ 6,451 $ 2,051 $ 2,977 $ 1,547 $ 1,430 $ 466 $ 809 $ 162 Other revenue sources (a) $ 177 $ 39 $ 68 $ 35 $ 32 $ 3 $ 10 $ 10 Total revenues $ 6,628 $ 2,090 $ 3,045 $ 1,582 $ 1,462 $ 469 $ 819 $ 172 (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. Nine Months Ended September 30, 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 $ 7,597 $ 2,331 $ 3,879 $ 1,657 $ 2,222 $ 563 $ 825 $ — General 4,896 1,714 2,225 1,044 1,181 335 619 — Industrial 2,339 927 708 514 194 109 595 — Wholesale 1,685 341 1,133 992 141 36 176 — Other revenues 557 222 389 239 150 59 66 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 17,074 $ 5,535 $ 8,334 $ 4,446 $ 3,888 $ 1,102 $ 2,281 $ — Gas Utilities and Infrastructure Residential $ 673 $ — $ — $ — $ — $ 229 $ — $ 443 Commercial 359 — — — — 96 — 263 Industrial 103 — — — — 14 — 91 Power Generation — — — — — — — 39 Other revenues 101 — — — — 13 — 88 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,236 $ — $ — $ — $ — $ 352 $ — $ 924 Commercial Renewables Revenue from contracts with customers $ 157 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 18 $ — $ — $ — $ — $ — $ — $ — Total Revenue from contracts with customers $ 18,485 $ 5,535 $ 8,334 $ 4,446 $ 3,888 $ 1,454 $ 2,281 $ 924 Other revenue sources (a) $ 491 $ 84 $ 224 $ 113 $ 99 $ (1 ) $ 8 $ 32 Total revenues $ 18,976 $ 5,619 $ 8,558 $ 4,559 $ 3,987 $ 1,453 $ 2,289 $ 956 (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. Nine Months Ended September 30, 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 $ 7,264 $ 2,263 $ 3,636 $ 1,540 $ 2,096 $ 564 $ 802 $ — General 4,619 1,608 2,109 972 1,137 318 584 — Industrial 2,235 893 678 481 197 96 567 — Wholesale 1,737 366 1,140 1,019 121 5 226 — Other revenues 558 261 359 222 137 57 66 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 16,413 $ 5,391 $ 7,922 $ 4,234 $ 3,688 $ 1,040 $ 2,245 $ — Gas Utilities and Infrastructure Residential $ 682 $ — $ — $ — $ — $ 236 $ — $ 446 Commercial 354 — — — — 97 — 257 Industrial 107 — — — — 13 — 93 Power Generation — — — — — — — 40 Other revenues 101 — — — — 13 — 88 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,244 $ — $ — $ — $ — $ 359 $ — $ 924 Commercial Renewables Revenue from contracts with customers $ 141 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 47 $ — $ — $ — $ — $ 36 $ — $ — Total Revenue from contracts with customers $ 17,845 $ 5,391 $ 7,922 $ 4,234 $ 3,688 $ 1,435 $ 2,245 $ 924 Other revenue sources (a) $ 561 $ 134 $ 197 $ 99 $ 92 $ 17 $ 43 $ 16 Total revenues $ 18,406 $ 5,525 $ 8,119 $ 4,333 $ 3,780 $ 1,452 $ 2,288 $ 940 (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. 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 Condensed Consolidated Balance Sheets as shown in the following table. (in millions) September 30, 2019 December 31, 2018 Duke Energy $ 831 $ 896 Duke Energy Carolinas 312 313 Progress Energy 265 244 Duke Energy Progress 141 148 Duke Energy Florida 124 96 Duke Energy Ohio 2 2 Duke Energy Indiana 19 23 Piedmont 2 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 Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 13 for further information. These receivables for unbilled revenues are shown in the table below. (in millions) September 30, 2019 December 31, 2018 Duke Energy Ohio $ 74 $ 86 Duke Energy Indiana 124 128

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS' EQUITY Basic EPS is computed by dividing net income attributable 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 attributable 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 restricted stock units that are entitled to dividends declared on Duke Energy common stock during the restricted stock unit’s vesting periods. Dividends declared on preferred stock are recorded on the income statement as a reduction of net income to arrive at net income attributable 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. Three Months Ended September 30, Nine Months Ended September 30, (in millions, except per-share amounts) 2019 2018 2019 2018 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 1,324 $ 1,077 $ 3,041 $ 2,199 Weighted average common shares outstanding – basic 729 713 728 705 Equity Forwards — 1 — 1 Weighted average common shares outstanding – diluted 729 714 728 706 EPS from continuing operations attributable to Duke Energy common stockholders Basic $ 1.82 $ 1.51 $ 4.18 $ 3.12 Diluted $ 1.82 $ 1.51 $ 4.18 $ 3.11 Potentially dilutive items excluded from the calculation (a) 2 2 2 2 Dividends declared per common share $ 0.945 $ 0.9275 $ 2.800 $ 2.7075 Dividends declared on Series A preferred stock per depositary share $ 0.359 $ — $ 0.667 $ — (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 On February 20, 2018, Duke Energy filed a prospectus supplement and executed an 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. The EDA was entered into with the Agents. Under the terms of the EDA, Duke Energy was allowed to issue and sell, through any of the Agents, shares of common stock. The existing ATM offering program expired on September 23, 2019. Duke Energy expects to reestablish an ATM offering program during November 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 . Separately, 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 2018, Duke Energy also issued 2.2 million shares through its DRIP with an increase in additional paid-in capital of approximately $174 million . For the nine months ended September 30, 2019 , Duke Energy issued 1.4 million shares through its DRIP with an increase in additional paid-in capital of approximately $120 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 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 agreements or net settle in whole or in part through the delivery or receipt of cash or shares. The settlement alternative is at Duke Energy's election. No amounts have or will be recorded in Duke Energy's Condensed Consolidated Financial Statements with respect to these ATM offerings until settlements of the equity forwards occur, which is expected by December 31, 2019. The initial forward sale price will be subject to adjustment based on a floating interest rate factor and other fixed amounts specified in the relevant forward sale agreements. Until settlement of the equity forwards, EPS dilution resulting from the agreements, if any, will be determined under the treasury stock method. 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 $990 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 semiannual 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 Duke Energy 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 of 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 or 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 Duke Energy Board of Directors.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 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 and non-qualified, non-contributory defined benefit retirement plans. 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. The following table includes information related to the Duke Energy Registrants' contributions to its qualified defined benefit pension plans. Nine Months Ended September 30, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Contributions made $ 77 $ 7 $ 57 $ 4 $ 53 $ 2 $ 2 $ 1 Duke Energy uses a December 31 measurement date for its qualified non-contributory defined benefit retirement plan assets and obligations. However, because Duke Energy believed it was probable in 2019 that total lump-sum benefit payments would exceed the settlement threshold, which is defined as the sum of the service cost and interest cost on projected benefit obligation components of net periodic pension costs, Duke Energy remeasured the plan assets and plan obligations associated with one of its qualified pension plans as of June 30, 2019, and September 30, 2019, (total lump-sum benefit payments exceeded the settlement threshold as of September 30, 2019). The discount rate used for the remeasurements was 3.5% and 3.2% as of June 30, 2019, and September 30, 2019, respectively. The cash balance interest crediting rate was 4.0% as of June 30, 2019, and September 30, 2019. All other assumptions used for the June 30, 2019, and September 30, 2019, remeasurements were consistent with the measurement as of December 31, 2018. As a result of the June 30, 2019, remeasurement, Duke Energy recognized a remeasurement gain of $18 million , which was recorded in Other within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets as of June 30, 2019. The remeasurement gain, which represents an increase in funded status, reflects an increase of $275 million in the fair value of plan assets and an increase of $257 million in the projected benefit obligation. As a result of the September 30, 2019, remeasurement, Duke Energy recognized a remeasurement loss of $136 million , which was recorded in Other within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets as of September 30, 2019. The remeasurement loss, which represents a decrease in funded status, reflects a decrease of $10 million in the fair value of plan assets and an increase of $126 million in the projected benefit obligation. As the result of settlement accounting, Duke Energy recognized settlement charges of $69 million and $16 million , primarily as a regulatory asset within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets as of June 30, 2019, and September 30, 2019, respectively (an immaterial amount was recorded in Other income and expenses, net within the Condensed Consolidated Statement of Operations). Settlement charges recognized by the Subsidiary Registrants as of June 30, 2019, were $43 million for Duke Energy Carolinas, $16 million for Duke Energy Progress, $3 million for Duke Energy Florida, $3 million for Duke Energy Indiana, $1 million for Duke Energy Ohio and $3 million for Piedmont. Settlement charges recognized by the Subsidiary Registrants as of September 30, 2019 were $6 million for Duke Energy Carolinas, $3 million for Duke Energy Progress, $2 million for Duke Energy Florida, $1 million for Duke Energy Indiana and $3 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 benefits payments as of September 30, 2019. QUALIFIED PENSION PLANS The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended September 30, 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 $ 42 $ 13 $ 13 $ 7 $ 5 $ 1 $ 2 $ 1 Interest cost on projected benefit obligation 77 17 24 10 14 5 6 2 Expected return on plan assets (140 ) (36 ) (45 ) (22 ) (22 ) (7 ) (11 ) (5 ) Amortization of actuarial loss 28 6 10 4 6 2 3 2 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (2 ) Net periodic pension costs $ (1 ) $ (2 ) $ 1 $ (1 ) $ 3 $ 1 $ — $ (2 ) Three Months Ended September 30, 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 $ 47 $ 15 $ 13 $ 7 $ 5 $ 2 $ 2 $ 2 Interest cost on projected benefit obligation 74 18 24 10 13 4 6 3 Expected return on plan assets (140 ) (37 ) (45 ) (21 ) (23 ) (7 ) (10 ) (6 ) Amortization of actuarial loss 33 7 11 6 6 1 2 3 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (3 ) Net periodic pension costs $ 6 $ 1 $ 2 $ 2 $ 1 $ — $ — $ (1 ) Nine Months Ended September 30, 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 $ 116 $ 37 $ 34 $ 19 $ 15 $ 3 $ 6 $ 4 Interest cost on projected benefit obligation 242 58 76 34 41 14 19 8 Expected return on plan assets (426 ) (111 ) (134 ) (66 ) (66 ) (21 ) (32 ) (16 ) Amortization of actuarial loss 77 17 28 10 18 3 6 5 Amortization of prior service credit (24 ) (6 ) (2 ) (1 ) (1 ) — (1 ) (7 ) Net periodic pension costs $ (15 ) $ (5 ) $ 2 $ (4 ) $ 7 $ (1 ) $ (2 ) $ (6 ) Nine Months Ended September 30, 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 $ 137 $ 45 $ 39 $ 22 $ 16 $ 4 $ 7 $ 6 Interest cost on projected benefit obligation 224 54 70 31 38 13 18 9 Expected return on plan assets (420 ) (111 ) (133 ) (63 ) (69 ) (21 ) (31 ) (18 ) Amortization of actuarial loss 99 21 33 16 18 3 6 9 Amortization of prior service credit (24 ) (6 ) (3 ) (1 ) (1 ) — — (9 ) Net periodic pension costs $ 16 $ 3 $ 6 $ 5 $ 2 $ (1 ) $ — $ (3 ) NON-QUALIFIED PENSION PLANS Net periodic pension costs for non-qualified pension plans were not material for the three and nine months ended September 30, 2019, and 2018. OTHER POST-RETIREMENT BENEFIT PLANS Net periodic costs for OPEB plans were not material for the three and nine months ended September 30, 2019, and 2018.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES EFFECTIVE TAX RATES The ETRs from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Duke Energy 12.4 % 13.7 % 12.5 % 17.0 % Duke Energy Carolinas 16.7 % 22.6 % 17.7 % 22.3 % Progress Energy 15.3 % 18.8 % 16.2 % 17.0 % Duke Energy Progress 14.7 % 20.6 % 16.1 % 18.4 % Duke Energy Florida 16.5 % 15.0 % 18.0 % 16.3 % Duke Energy Ohio 12.9 % 16.0 % 15.2 % 16.0 % Duke Energy Indiana 23.2 % 22.7 % 23.7 % 24.7 % Piedmont 35.7 % 34.4 % 18.5 % 20.6 % The decrease in the ETR for Duke Energy for the three months ended September 30, 2019, was primarily due to an increase in the amortization of excess deferred taxes. The decrease in the ETR for Duke Energy for the nine months ended September 30, 2019 , was primarily due to a one-time valuation allowance charge in the prior year, an adjustment related to the income tax recognition for equity method investments recorded in the first quarter of 2019 and an increase in the amortization of excess deferred taxes. The equity method investment adjustment was immaterial and relates to prior years. The decrease in the ETR for Duke Energy Carolinas for the three and nine months ended September 30, 2019 , was primarily due to an increase in the amortization of excess deferred taxes. The decrease in the ETR for Progress Energy for the three months ended September 30, 2019 , was primarily due to an increase in the amortization of excess deferred taxes and favorable tax return true ups partially offset by a decrease in AFUDC equity in the current year. The decrease in the ETR for Duke Energy Progress for the three and nine months ended September 30, 2019 , was primarily due to an increase in the amortization of excess deferred taxes and favorable tax return true ups. The increase in the ETR for Duke Energy Florida for the three and nine months ended September 30, 2019 , was primarily due to a decrease in AFUDC equity in the current year. The decrease in the ETR for Duke Energy Ohio for the three months ended September 30, 2019 , was primarily due to an increase in the amortization of excess deferred taxes. The increase in the ETR, in relation to pretax losses, for Piedmont for the three months ended September 30, 2019 , was primarily due to an increase in the amortization of excess deferred taxes and partially offset by a decrease in favorable tax return true ups. The decrease in the ETR for the nine months ended September 30, 2019 , was primarily due to an increase in the amortization of excess deferred taxes and partially offset by a decrease in favorable tax return true ups. OTHER TAX MATTERS On October 23, 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.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on subsequent events related to regulatory matters, stockholders' equity and income taxes, see Notes 3, 15 and 17, respectively.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Policy)	9 Months Ended
	Sep. 30, 2019
Policy Text Block [Line Items]
Basis of Presentation	BASIS OF PRESENTATION These Condensed Consolidated Financial Statements have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all information and notes required by GAAP for annual financial statements and should be read in conjunction with the Consolidated Financial Statements in the Duke Energy Registrants’ combined Annual Report on Form 10-K for the year ended December 31, 2018 . The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants make any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. These Condensed Consolidated Financial Statements, in the opinion of the respective companies’ management, reflect all normal recurring adjustments necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors. In preparing financial statements that conform to GAAP, management 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.
Basis of Consolidation and Noncontrolling Interest	BASIS OF CONSOLIDATION These Condensed 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 13 for additional information on VIEs. These Condensed Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. 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 Condensed Consolidated Balance Sheet. Several operating agreements of Duke Energy's subsidiaries with noncontrolling interest are subject to allocations of earnings, 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 book profit 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 profit or loss allocated to each owner for the reporting period. Duke Energy’s North Rosamond solar farm commenced commercial operations resulting in the allocation of losses to the noncontrolling tax equity members of $12 million and $86 million for the three and nine months ended September 30, 2019 , respectively, utilizing the HLBV method. 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 a 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.
Cash, Cash Equivalents, and Restricted Cash	CASH, CASH EQUIVALENTS AND RESTRICTED CASH Duke Energy, Progress Energy and Duke Energy Florida have restricted cash balances related primarily to collateral assets, escrow deposits and VIEs. See Note 13
New Accounting Standards	NEW ACCOUNTING STANDARDS Except as noted below, the new accounting standards adopted for 2018 and 2019 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 September 30, 2019 , and an immaterial impact to the Duke Energy Registrants' results of operations for the three and nine months ended September 30, 2019 , and cash flows for the nine months ended September 30, 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 has 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 5 for further information. The following new accounting standard has been issued but not yet adopted by the Duke Energy Registrants as of September 30, 2019 . Credit Losses. In June 2016, the FASB issued new accounting guidance for credit losses. This guidance establishes the new CECL 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.
Environmental Costs	Costs are typically expensed as Operation, maintenance and other on the Condensed Consolidated Statements of Operations unless regulatory recovery of the costs is deemed probable.Liabilities are recorded when losses become probable and are reasonably estimable.
Derivatives	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 Condensed Consolidated Statements of Operations and Comprehensive Income.
Investments	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.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.
Revenue from Contract with Customer	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.
Earnings Per Share	Basic EPS is computed by dividing net income attributable 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 attributable 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 restricted stock units that are entitled to dividends declared on Duke Energy common stock during the restricted stock unit’s vesting periods. Dividends declared on preferred stock are recorded on the income statement as a reduction of net income to arrive at net income attributable 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.

Organization and Basis of Pre_3

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2019
Organization And Basis Of Presentation [Line Items]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table presents the components of cash, cash equivalents and restricted cash included in the Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 379 $ 82 $ 24 $ 442 $ 67 $ 36 Other 163 16 16 141 39 39 Other Noncurrent Assets Other 40 38 — 8 6 — Total cash, cash equivalents and restricted cash $ 582 $ 136 $ 40 $ 591 $ 112 $ 75
Schedule of Utility Inventory	The components of inventory are presented in the tables below. September 30, 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 $ 2,284 $ 749 $ 1,056 $ 710 $ 346 $ 75 $ 325 $ 4 Coal 490 153 172 118 54 12 152 — Natural gas, oil and other fuel 333 41 206 111 95 41 1 43 Total inventory $ 3,107 $ 943 $ 1,434 $ 939 $ 495 $ 128 $ 478 $ 47 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 fuel 355 42 218 114 103 28 1 68 Total inventory $ 3,084 $ 948 $ 1,459 $ 954 $ 504 $ 126 $ 422 $ 70
Schedule of New Accounting Pronouncements	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 September 30, 2019 , and an immaterial impact to the Duke Energy Registrants' results of operations for the three and nine months ended September 30, 2019 , and cash flows for the nine months ended September 30, 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 has 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).

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting Information [Line Items]
Business Segment Data	Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Three Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 6,569 $ 225 $ 138 $ 6,932 $ 8 $ — $ 6,940 Intersegment revenues 8 24 — 32 17 (49 ) — Total revenues $ 6,577 $ 249 $ 138 $ 6,964 $ 25 $ (49 ) $ 6,940 Segment income (loss) (a) $ 1,385 $ 26 $ 40 $ 1,451 $ (124 ) $ — $ 1,327 Add back noncontrolling interests (b) (19 ) Add back preferred stock dividend 15 Net income $ 1,323 Segment assets $ 133,296 $ 13,424 $ 5,278 $ 151,998 $ 3,734 $ 185 $ 155,917 Three Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 6,253 $ 232 $ 127 $ 6,612 $ 16 $ — $ 6,628 Intersegment revenues 7 24 — 31 18 (49 ) — Total revenues $ 6,260 $ 256 $ 127 $ 6,643 $ 34 $ (49 ) $ 6,628 Segment income (loss) (c)(d)(e) $ 1,167 $ 17 $ (62 ) $ 1,122 $ (44 ) $ — $ 1,078 Add back noncontrolling interests (16 ) Loss from discontinued operations, net of tax 4 Net income $ 1,066 Nine Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 17,357 $ 1,239 $ 362 $ 18,958 $ 18 $ — $ 18,976 Intersegment revenues 24 72 — 96 53 (149 ) — Total revenues $ 17,381 $ 1,311 $ 362 $ 19,054 $ 71 $ (149 ) $ 18,976 Segment income (loss) (a) $ 2,944 $ 292 $ 139 $ 3,375 $ (328 ) $ — $ 3,047 Add back noncontrolling interests (b) (110 ) Add back preferred stock dividend 27 Net income $ 2,964 Nine Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 16,783 $ 1,229 $ 347 $ 18,359 $ 47 $ — $ 18,406 Intersegment revenues 23 72 — 95 54 (149 ) — Total revenues $ 16,806 $ 1,301 $ 347 $ 18,454 $ 101 $ (149 ) $ 18,406 Segment income (loss) (c)(d)(e)(f)(g)(h) $ 2,492 $ 161 $ (4 ) $ 2,649 $ (446 ) $ — $ 2,203 Add back noncontrolling interests (12 ) Loss from discontinued operations, net of tax (1 ) Net income $ 2,190 (a) Electric Utilities and Infrastructure includes a reduction of a prior year impairment at Citrus County CC related to the plant's cost cap. See Note 3 for additional information. (b) Includes the allocation of losses to noncontrolling tax equity members. See Note 1 for additional information. (c) All segments include adjustments of prior year tax estimates related to the Tax Act. (d) Commercial Renewables includes an impairment charge related to goodwill. (e) Other includes costs to achieve the Piedmont acquisition. (f) Electric Utilities and Infrastructure includes regulatory and legislative charges related to rate case orders, settlements or other actions of regulators or legislative bodies. See Note 3 for additional information. (g) Gas Utilities and Infrastructure includes an impairment of the investment in Constitution. See Note 3 for additional information. (h) Other includes the loss on the sale of Beckjord described below and a valuation allowance recorded against the AMT credits.
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data	Three Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 408 $ 81 $ 489 $ — $ — $ 489 Segment income/Net (loss) income $ 62 $ 13 $ 75 $ (1 ) $ — $ 74 Segment assets $ 6,107 $ 3,049 $ 9,156 $ 30 $ (3 ) $ 9,183 Three Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 373 $ 84 $ 457 $ 12 $ 469 Segment income/Net income $ 85 $ 12 $ 97 $ 3 $ 100 Nine Months Ended September 30, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 1,099 $ 354 $ 1,453 $ — $ 1,453 Segment income/Net (loss) income $ 129 $ 65 $ 194 $ (4 ) $ 190 Nine Months Ended September 30, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 1,055 $ 361 $ 1,416 $ 36 $ 1,452 Segment income/Net (loss) income (a) $ 157 $ 64 $ 221 $ (100 ) $ 121 (a) Other includes the loss on the sale of Beckjord described above.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2019
Regulated Operations [Abstract]
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 Condensed Consolidated Balance Sheets as of September 30, 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 $ 154 Duke Energy Indiana Gallagher Units 2 and 4 (b) 280 116 Gibson Units 1-5 (c) 3,132 1,949 Cayuga Units 1-2 (c) 1,005 974 Total Duke Energy 5,002 $ 3,193 (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.

Commitments and Contingencies (

Commitments and Contingencies (Table)	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
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 $ 49 Duke Energy Carolinas 11 Duke Energy Ohio 31 Piedmont 2
Schedule of Reserves	The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos-related reserves discussed above. Reserves are classified on the Condensed 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. (in millions) September 30, 2019 December 31, 2018 Reserves for Legal Matters Duke Energy $ 62 $ 65 Duke Energy Carolinas 8 9 Progress Energy 52 54 Duke Energy Progress 13 12 Duke Energy Florida 22 24 Piedmont 1 1 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 Condensed Consolidated Balance Sheets. Nine Months Ended September 30, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 77 $ 11 $ 11 $ 4 $ 6 $ 48 $ 5 $ 2 Provisions/adjustments 30 4 9 3 5 10 — 6 Cash reductions (35 ) (4 ) (3 ) (2 ) (1 ) (28 ) — — Balance at end of period $ 72 $ 11 $ 17 $ 5 $ 10 $ 30 $ 5 $ 8 Nine Months Ended September 30, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 81 $ 10 $ 15 $ 3 $ 12 $ 47 $ 5 $ 2 Provisions/adjustments 7 3 2 3 (1 ) 3 1 — Cash reductions (20 ) (2 ) (5 ) (1 ) (4 ) (12 ) (1 ) — Balance at end of period $ 68 $ 11 $ 12 $ 5 $ 7 $ 38 $ 5 $ 2

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 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. September 30, 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 $ 1,703 $ 135 $ 814 $ 397 $ 417 $ 22 $ 58 $ 25 Finance Net property, plant and equipment 952 125 448 309 139 — 10 — Total lease assets $ 2,655 $ 260 $ 1,262 $ 706 $ 556 $ 22 $ 68 $ 25 Liabilities Current Operating Other current liabilities $ 212 $ 27 $ 99 $ 36 $ 63 $ 1 $ 3 $ 4 Finance Current maturities of long-term debt 117 6 23 6 17 — — — Noncurrent Operating Operating lease liabilities 1,456 108 710 360 350 21 55 24 Finance Long-Term Debt 873 100 385 302 83 — 10 — Total lease liabilities $ 2,658 $ 241 $ 1,217 $ 704 $ 513 $ 22 $ 68 $ 28
Lease Costs and Cash Flows Information	The following tables present the components of lease expense. Three Months Ended September 30, 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) $ 75 $ 13 $ 39 $ 16 $ 23 $ 3 $ 5 $ 1 Short-term lease expense (a) 2 — — — — — 1 — Variable lease expense (a) 27 6 22 21 1 — — — Finance lease expense Amortization of leased assets (b) 28 2 9 1 8 — — — Interest on lease liabilities (c) 7 3 12 10 2 — — — Total finance lease expense 35 5 21 11 10 — — — Total lease expense $ 139 $ 24 $ 82 $ 48 $ 34 $ 3 $ 6 $ 1 Nine Months Ended September 30, 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) $ 220 $ 36 $ 121 $ 52 $ 69 $ 9 $ 15 $ 4 Short-term lease expense (a) 15 4 7 3 4 1 2 — Variable lease expense (a) 48 18 29 24 5 — — — Finance lease expense Amortization of leased assets (b) 84 4 17 3 14 1 — — Interest on lease liabilities (c) 44 10 31 24 7 — 1 — Total finance lease expense 128 14 48 27 21 1 1 — Total lease expense $ 411 $ 72 $ 205 $ 106 $ 99 $ 11 $ 18 $ 4 (a) Included in Operations, maintenance and other or, for barges and railcars, Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations. (b) Included in Depreciation and amortization on the Condensed Consolidated Statements of Operations. (c) Included in Interest Expense on the Condensed Consolidated Statements of Operations. Nine Months Ended September 30, 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 $ 221 $ 26 $ 104 $ 43 $ 61 $ 1 $ 5 $ 6 Operating cash flows from finance leases 44 10 31 24 7 — 1 — Financing cash flows from finance leases 84 4 17 3 14 1 — — Lease assets obtained in exchange for new lease liabilities (non-cash) Operating (b) $ 147 $ 44 $ 30 $ 30 $ — $ — $ — $ 1 Finance 175 — 175 175 — — — — (a) No amounts were classified as investing cash flows from operating leases for the nine months ended September 30, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard.
Schedule of Rent Expense	The following table presents rental expense for operating leases, as reported under the old lease standard. These amounts are included in Operation, maintenance and other and Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations. (in millions) Year Ended December 31, 2018 Duke Energy $ 268 Duke Energy Carolinas 49 Progress Energy 143 Duke Energy Progress 75 Duke Energy Florida 68 Duke Energy Ohio 13 Duke Energy Indiana 21 Piedmont 11
Lessee, Operating Lease, Liability, Maturity	The following table presents operating lease maturities and a reconciliation of the undiscounted cash flows to operating lease liabilities. Twelve Months Ended September 30, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 278 $ 32 $ 129 $ 51 $ 78 $ 2 $ 6 $ 5 2021 220 20 100 45 55 2 4 5 2022 201 19 95 40 55 2 4 5 2023 192 18 95 41 54 2 4 5 2024 179 14 95 41 54 2 4 5 Thereafter 1,008 60 480 291 189 22 63 6 Total operating lease payments 2,078 163 994 509 485 32 85 31 Less: present value discount (410 ) (28 ) (185 ) (113 ) (72 ) (10 ) (27 ) (3 ) Total operating lease liabilities (a) $ 1,668 $ 135 $ 809 $ 396 $ 413 $ 22 $ 58 $ 28 (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 old 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. Twelve Months Ended September 30, Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana 2020 $ 179 $ 19 $ 69 $ 44 $ 25 $ 1 2021 184 16 69 44 25 1 2022 177 14 69 44 25 1 2023 173 14 69 44 25 1 2024 149 14 57 44 13 1 Thereafter 827 189 552 539 13 27 Total finance lease payments 1,689 266 885 759 126 32 Less: amounts representing interest (699 ) (160 ) (477 ) (451 ) (26 ) (22 ) Total finance lease liabilities $ 990 $ 106 $ 408 $ 308 $ 100 $ 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 old 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
Lessee, Lease, Supplemental Information	September 30, 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 18 18 6 Finance leases 13 18 16 18 11 — 27 — Weighted-average discount rate (a) Operating leases 3.9 % 3.5 % 3.8 % 3.9 % 3.8 % 4.3 % 4.1 % 3.6 % Finance leases 8.0 % 12.9 % 11.8 % 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)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table shows the significant components of Current Maturities of Long-Term Debt on the Condensed 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 September 30, 2019 Unsecured Debt Duke Energy Kentucky October 2019 4.650 % $ 100 Progress Energy December 2019 4.875 % 350 Duke Energy (Parent) June 2020 2.100 % 330 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 2.282 % (a) 300 Other (b) 566 Current maturities of long-term debt $ 3,096 (a) Debt issuance has a floating interest rate. (b) Includes finance lease obligations, amortizing debt and small bullet maturities. The following table summarizes significant debt issuances (in millions). Nine Months Ended September 30, 2019 Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Ohio Indiana Piedmont Unsecured Debt March 2019 (a) March 2022 2.788 % (b) $ 300 $ 300 $ — $ — $ — $ — $ — March 2019 (a) March 2022 3.227 % 300 300 — — — — — May 2019 (e) June 2029 3.500 % 600 — — — — — 600 June 2019 (a) June 2029 3.400 % 600 600 — — — — — June 2019 (a) June 2049 4.200 % 600 600 — — — — — July 2019 (g) July 2049 4.320 % 40 — — — 40 — — September 2019 (g) October 2025 3.230 % 95 — — — 95 — — September 2019 (g) October 2029 3.560 % 75 — — — 75 — — First Mortgage Bonds January 2019 (c) February 2029 3.650 % 400 — — — 400 — — January 2019 (c) February 2049 4.300 % 400 — — — 400 — — March 2019 (d) March 2029 3.450 % 600 — — 600 — — — August 2019 (a) August 2029 2.450 % 450 — 450 — — — — August 2019 (a) August 2049 3.200 % 350 — 350 — — — — September 2019 (f) October 2049 3.250 % 500 — — — — 500 — Total issuances $ 5,310 $ 1,800 $ 800 $ 600 $ 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.
Schedule Of Line Of Credit Facilities	Other Credit Facilities September 30, 2019 (in millions) Facility size Amount drawn Duke Energy (Parent) Three-Year Revolving Credit Facility (a) $ 1,000 $ 500 Duke Energy Progress Term Loan Facility 700 700 (a) In May 2019, Duke Energy (Parent) extended the termination date to May 2022. September 30, 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 $ 1,750 $ 1,250 $ 800 $ 450 $ 600 $ 500 Reduction to backstop issuances Commercial paper (b) (1,971 ) (627 ) (338 ) (211 ) (277 ) (164 ) (150 ) (204 ) Outstanding letters of credit (51 ) (43 ) (4 ) (2 ) — — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity under the Master Credit Facility $ 5,397 $ 1,980 $ 1,158 $ 787 $ 523 $ 286 $ 369 $ 294 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2019
Asset Retirement Obligation [Abstract]
Schedule of Asset Retirement Obligations	The following table presents the AROs recorded on the Condensed Consolidated Balance Sheets. September 30, 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) $ 5,789 $ 2,435 $ 3,295 $ 2,769 $ 526 $ — $ — $ — Closure of ash impoundments 6,486 2,917 2,722 2,707 15 43 804 — Other 326 46 71 38 33 42 20 20 Total ARO $ 12,601 $ 5,398 $ 6,088 $ 5,514 $ 574 $ 85 $ 824 $ 20 Less: current portion 861 214 478 476 2 3 165 — Total noncurrent ARO $ 11,740 $ 5,184 $ 5,610 $ 5,038 $ 572 $ 82 $ 659 $ 20 (a) Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy.
Schedule of Change in Asset Retirement Obligation	The following table presents the change in liability associated with AROs for the Duke Energy Registrants. 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 (a) $ 10,467 $ 3,949 $ 5,411 $ 4,820 $ 591 $ 93 $ 722 $ 19 Accretion expense (b) 377 173 190 171 19 3 21 1 Liabilities settled (c) (691 ) (276 ) (375 ) (341 ) (34 ) (9 ) (32 ) — Revisions in estimates of cash flows (d) 2,448 1,552 862 864 (2 ) (2 ) 113 — Balance at September 30, 2019 $ 12,601 $ 5,398 $ 6,088 $ 5,514 $ 574 $ 85 $ 824 $ 20 (a) Primarily relates to decommissioning nuclear power facilities, closure of ash impoundments, asbestos removal, closure of landfills at fossil generation facilities, retirement of natural gas mains and removal of renewable energy generation assets. (b) For the nine months ended September 30, 2019 , substantially all accretion expense relates to Duke Energy's regulated operations and has been deferred in accordance with regulatory accounting treatment. (c) Primarily relates to ash impoundment closures. (d) Primarily relates to increases in closure estimates for certain ash impoundments as a result of the NCDEQ's April 1 Order. See Note 4 for more information. The incremental amount recorded represents the discounted cash flows for estimated closure costs based upon the probability weightings of the potential closure methods as evaluated on a site-by-site basis.
Public Utilities General Disclosures	(in millions) September 30, 2019 December 31, 2018 Duke Energy $ 6,403 $ 5,579 Duke Energy Carolinas 3,614 3,133 Duke Energy Progress 2,789 2,446

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill By Reportable Operating Segment	The following table presents the goodwill by reportable segment included on Duke Energy's Condensed Consolidated Balance Sheets at September 30, 2019 , and December 31, 2018 . Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill balance $ 17,379 $ 1,924 $ 122 $ 19,425 Accumulated impairment charges — — (122 ) (122 ) Goodwill, adjusted for accumulated impairment charges $ 17,379 $ 1,924 $ — $ 19,303

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2019
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	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 September 30, 2019 Intercompany income tax receivable $ — $ 178 $ 60 $ 10 $ 14 $ 3 $ 85 Intercompany income tax payable 71 — — — — — — December 31, 2018 Intercompany income tax receivable $ 52 $ 47 $ 29 $ — $ — $ 8 $ — Intercompany income tax payable — — — 16 3 — 45 Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 197 $ 214 $ 606 $ 647 Indemnification coverages (b) 5 6 15 17 JDA revenue (c) 12 13 52 66 JDA expense (c) 32 61 145 134 Intercompany natural gas purchases (d) — 3 7 11 Progress Energy Corporate governance and shared service expenses (a) $ 194 $ 216 $ 553 $ 613 Indemnification coverages (b) 8 8 27 25 JDA revenue (c) 32 61 145 134 JDA expense (c) 12 13 52 66 Intercompany natural gas purchases (d) 19 20 57 58 Duke Energy Progress Corporate governance and shared service expenses (a) $ 114 $ 138 $ 328 $ 382 Indemnification coverages (b) 3 3 11 9 JDA revenue (c) 32 61 145 134 JDA expense (c) 12 13 52 66 Intercompany natural gas purchases (d) 19 20 57 58 Duke Energy Florida Corporate governance and shared service expenses (a) $ 80 $ 78 $ 225 $ 231 Indemnification coverages (b) 5 5 16 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 90 $ 85 $ 258 $ 264 Indemnification coverages (b) 1 1 3 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 109 $ 105 $ 299 $ 302 Indemnification coverages (b) 2 2 5 6 Piedmont Corporate governance and shared service expenses (a) $ 33 $ 39 $ 102 $ 115 Indemnification coverages (b) 1 1 2 2 Intercompany natural gas sales (d) 19 23 64 69 Natural gas storage and transportation costs (e) 6 6 17 18 (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 Condensed 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 Condensed 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 Condensed 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 Condensed Consolidated Statements of Operations and Comprehensive Income. (e)

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	The following table shows notional amounts of outstanding derivatives related to interest rate risk. September 30, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 1,031 $ — $ — $ — $ — $ — Undesignated contracts 1,577 450 1,100 250 850 27 Total notional amount (a) $ 2,608 $ 450 $ 1,100 $ 250 $ 850 $ 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 $ 923 $ — $ — $ — $ — $ — Undesignated contracts 1,721 300 1,200 650 550 27 Total notional amount (a) $ 2,644 $ 300 $ 1,200 $ 650 $ 550 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $731 million in cash flow hedges as of September 30, 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. September 30, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 25,658 — — — — 2,774 22,884 — Natural gas (millions of dekatherms) 729 130 175 175 — — 4 420 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 dekatherms) 739 121 169 166 3 — 1 448
Location And Fair Value Of Derivatives Recognized in the Condensed 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 Condensed 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 September 30, 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 $ 23 $ — $ — $ — $ — $ 5 $ 16 $ 2 Total Derivative Assets – Commodity Contracts $ 23 $ — $ — $ — $ — $ 5 $ 16 $ 2 Interest Rate Contracts Designated as Hedging Instruments Current $ 3 $ — $ — $ — $ — $ — $ — $ — Total Derivative Assets – Interest Rate Contracts $ 3 $ — $ — $ — $ — $ — $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 5 — 5 — 5 — — — Total Derivative Assets – Equity Securities Contracts $ 5 $ — $ 5 $ — $ 5 $ — $ — $ — Total Derivative Assets $ 31 $ — $ 5 $ — $ 5 $ 5 $ 16 $ 2 Derivative Liabilities September 30, 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 $ 66 $ 33 $ 24 $ 24 $ — $ — $ — $ 9 Noncurrent 147 12 34 18 — — — 102 Total Derivative Liabilities – Commodity Contracts $ 213 $ 45 $ 58 $ 42 $ — $ — $ — $ 111 Interest Rate Contracts Designated as Hedging Instruments Current $ 2 $ — $ — $ — $ — $ — $ — $ — Noncurrent 56 — — — — — — — Not Designated as Hedging Instruments Current 64 22 42 1 41 1 — — Noncurrent 8 — 3 — 3 5 — — Total Derivative Liabilities – Interest Rate Contracts $ 130 $ 22 $ 45 $ 1 $ 44 $ 6 $ — $ — Equity Securities Contracts Not Designated as Hedging Instruments Current 10 — 10 — 10 — — — Total Derivative Liabilities – Equity Securities Contracts $ 10 $ — $ 10 $ — $ 10 $ — $ — $ — Total Derivative Liabilities $ 353 $ 67 $ 113 $ 43 $ 54 $ 6 $ — $ 111 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 Condensed 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 September 30, 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 $ 31 $ — $ 5 $ — $ 5 $ 5 $ 16 $ 2 Gross amounts offset (5 ) — (5 ) — (5 ) — — — Net amounts presented in Current Assets: Other $ 26 $ — $ — $ — $ — $ 5 $ 16 $ 2 Derivative Liabilities September 30, 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 $ 142 $ 55 $ 76 $ 25 $ 51 $ 1 $ — $ 9 Gross amounts offset (10 ) — (10 ) — (10 ) — — — Net amounts presented in Current Liabilities: Other $ 132 $ 55 $ 66 $ 25 $ 41 $ 1 $ — $ 9 Noncurrent Gross amounts recognized $ 211 $ 12 $ 37 $ 18 $ 3 $ 5 $ — $ 102 Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 211 $ 12 $ 37 $ 18 $ 3 $ 5 $ — $ 102 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
Offsetting Liabilities	Derivative Assets September 30, 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 $ 31 $ — $ 5 $ — $ 5 $ 5 $ 16 $ 2 Gross amounts offset (5 ) — (5 ) — (5 ) — — — Net amounts presented in Current Assets: Other $ 26 $ — $ — $ — $ — $ 5 $ 16 $ 2 Derivative Liabilities September 30, 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 $ 142 $ 55 $ 76 $ 25 $ 51 $ 1 $ — $ 9 Gross amounts offset (10 ) — (10 ) — (10 ) — — — Net amounts presented in Current Liabilities: Other $ 132 $ 55 $ 66 $ 25 $ 41 $ 1 $ — $ 9 Noncurrent Gross amounts recognized $ 211 $ 12 $ 37 $ 18 $ 3 $ 5 $ — $ 102 Gross amounts offset — — — — — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 211 $ 12 $ 37 $ 18 $ 3 $ 5 $ — $ 102 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
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. September 30, 2019 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 82 $ 40 $ 42 $ 42 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 82 40 42 42 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

Investments in Debt and Equit_2

Investments in Debt and Equity Securities (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Trading, and Equity Securities, FV-NI	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 114 $ — $ — $ 88 Equity securities 3,118 63 5,222 2,402 95 4,475 Corporate debt securities 40 1 633 4 13 566 Municipal bonds 14 — 370 1 4 353 U.S. government bonds 39 — 1,217 14 12 1,076 Other debt securities 4 — 142 — 2 148 Total NDTF Investments $ 3,215 $ 64 $ 7,698 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 53 $ — $ — $ 22 Equity securities 48 — 112 36 1 99 Corporate debt securities 2 — 72 — 2 60 Municipal bonds 5 — 94 — 1 85 U.S. government bonds 3 — 40 1 — 45 Other debt securities 1 — 65 — 1 58 Total Other Investments $ 59 $ — $ 436 $ 37 $ 5 $ 369 Total Investments $ 3,274 $ 64 $ 8,134 $ 2,458 $ 131 $ 7,075
Debt Securities, Available-for-sale	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 114 $ — $ — $ 88 Equity securities 3,118 63 5,222 2,402 95 4,475 Corporate debt securities 40 1 633 4 13 566 Municipal bonds 14 — 370 1 4 353 U.S. government bonds 39 — 1,217 14 12 1,076 Other debt securities 4 — 142 — 2 148 Total NDTF Investments $ 3,215 $ 64 $ 7,698 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 53 $ — $ — $ 22 Equity securities 48 — 112 36 1 99 Corporate debt securities 2 — 72 — 2 60 Municipal bonds 5 — 94 — 1 85 U.S. government bonds 3 — 40 1 — 45 Other debt securities 1 — 65 — 1 58 Total Other Investments $ 59 $ — $ 436 $ 37 $ 5 $ 369 Total Investments $ 3,274 $ 64 $ 8,134 $ 2,458 $ 131 $ 7,075
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. September 30, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Due in one year or less $ 400 $ 65 $ 328 $ 48 $ 280 $ 4 Due after one through five years 524 220 253 243 10 15 Due after five through 10 years 450 187 209 201 8 5 Due after 10 years 1,259 687 465 431 34 19 Total $ 2,633 $ 1,159 $ 1,255 $ 923 $ 332 $ 43
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 three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 60 $ 19 $ 161 $ 85 Realized losses 43 16 136 60 AFS: Realized gains 53 4 110 14 Realized losses 36 7 83 32
Duke Energy Carolinas [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Trading, and Equity Securities, FV-NI	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 36 $ — $ — $ 29 Equity securities 1,680 15 2,901 1,309 54 2,484 Corporate debt securities 24 1 409 2 9 341 Municipal bonds 4 — 96 — 1 81 U.S. government bonds 19 — 517 5 8 475 Other debt securities 4 — 137 — 2 143 Total NDTF Investments $ 1,731 $ 16 $ 4,096 $ 1,316 $ 74 $ 3,553
Debt Securities, Available-for-sale	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 36 $ — $ — $ 29 Equity securities 1,680 15 2,901 1,309 54 2,484 Corporate debt securities 24 1 409 2 9 341 Municipal bonds 4 — 96 — 1 81 U.S. government bonds 19 — 517 5 8 475 Other debt securities 4 — 137 — 2 143 Total NDTF Investments $ 1,731 $ 16 $ 4,096 $ 1,316 $ 74 $ 3,553
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 three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 34 $ 11 $ 101 $ 47 Realized losses 26 8 95 30 AFS: Realized gains 21 4 46 13 Realized losses 13 6 34 24
Progress Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Trading, and Equity Securities, FV-NI	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 78 $ — $ — $ 59 Equity securities 1,438 48 2,321 1,093 41 1,991 Corporate debt securities 16 — 224 2 4 225 Municipal bonds 10 — 274 1 3 272 U.S. government bonds 20 — 700 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,484 $ 48 $ 3,602 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 49 $ — $ — $ 17 Municipal bonds 4 — 52 — — 47 Total Other Investments $ 4 $ — $ 101 $ — $ — $ 64 Total Investments $ 1,488 $ 48 $ 3,703 $ 1,105 $ 52 $ 3,217
Debt Securities, Available-for-sale	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 78 $ — $ — $ 59 Equity securities 1,438 48 2,321 1,093 41 1,991 Corporate debt securities 16 — 224 2 4 225 Municipal bonds 10 — 274 1 3 272 U.S. government bonds 20 — 700 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,484 $ 48 $ 3,602 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 49 $ — $ — $ 17 Municipal bonds 4 — 52 — — 47 Total Other Investments $ 4 $ — $ 101 $ — $ — $ 64 Total Investments $ 1,488 $ 48 $ 3,703 $ 1,105 $ 52 $ 3,217
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 three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 26 $ 8 $ 60 $ 38 Realized losses 17 8 41 30 AFS: Realized gains 31 — 62 1 Realized losses 23 1 49 8
Duke Energy Progress [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Trading, and Equity Securities, FV-NI	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 46 Equity securities 1,107 30 1,907 833 30 1,588 Corporate debt securities 16 — 224 2 3 171 Municipal bonds 10 — 274 1 3 271 U.S. government bonds 19 — 420 6 3 415 Other debt securities — — 5 — — 3 Total NDTF Investments $ 1,152 $ 30 $ 2,882 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Total Other Investments $ — $ — $ 2 $ — $ — $ 6 Total Investments $ 1,152 $ 30 $ 2,884 $ 842 $ 39 $ 2,500
Debt Securities, Available-for-sale	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 46 Equity securities 1,107 30 1,907 833 30 1,588 Corporate debt securities 16 — 224 2 3 171 Municipal bonds 10 — 274 1 3 271 U.S. government bonds 19 — 420 6 3 415 Other debt securities — — 5 — — 3 Total NDTF Investments $ 1,152 $ 30 $ 2,882 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Total Other Investments $ — $ — $ 2 $ — $ — $ 6 Total Investments $ 1,152 $ 30 $ 2,884 $ 842 $ 39 $ 2,500
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 three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 10 $ 7 $ 27 $ 32 Realized losses 9 7 24 27 AFS: Realized gains 2 — 4 1 Realized losses — 1 2 6
Duke Energy Florida [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Trading, and Equity Securities, FV-NI	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 26 $ — $ — $ 13 Equity securities 331 18 414 260 11 403 Corporate debt securities — — — — 1 54 Municipal bonds — — — — — 1 U.S. government bonds 1 — 280 3 1 186 Other debt securities — — — — — 2 Total NDTF Investments (a) $ 332 $ 18 $ 720 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 1 Municipal bonds 4 — 52 — — 47 Total Other Investments $ 4 $ — $ 56 $ — $ — $ 48 Total Investments $ 336 $ 18 $ 776 $ 263 $ 13 $ 707 (a) During the nine months ended September 30, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of Crystal River Unit 3.
Debt Securities, Available-for-sale	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 26 $ — $ — $ 13 Equity securities 331 18 414 260 11 403 Corporate debt securities — — — — 1 54 Municipal bonds — — — — — 1 U.S. government bonds 1 — 280 3 1 186 Other debt securities — — — — — 2 Total NDTF Investments (a) $ 332 $ 18 $ 720 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 1 Municipal bonds 4 — 52 — — 47 Total Other Investments $ 4 $ — $ 56 $ — $ — $ 48 Total Investments $ 336 $ 18 $ 776 $ 263 $ 13 $ 707 (a) During the nine months ended September 30, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of Crystal River Unit 3.
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 three and nine months ended September 30, 2019 , and 2018, were as follows. Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 FV-NI: Realized gains $ 16 $ 1 $ 33 $ 6 Realized losses 8 1 17 3 AFS: Realized gains 29 — 58 — Realized losses 23 — 47 2
Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Trading, and Equity Securities, FV-NI	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value Investments Equity securities $ 37 $ — $ 74 $ 29 $ — $ 67 Corporate debt securities — — 6 — — 8 Municipal bonds 1 — 36 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 38 $ — $ 117 $ 29 $ 1 $ 108
Debt Securities, Available-for-sale	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. September 30, 2019 December 31, 2018 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value Investments Equity securities $ 37 $ — $ 74 $ 29 $ — $ 67 Corporate debt securities — — 6 — — 8 Municipal bonds 1 — 36 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 38 $ — $ 117 $ 29 $ 1 $ 108

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 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 Condensed Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type for the Duke Energy Registrants. September 30, 2019 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 5,222 $ 5,168 $ — $ — $ 54 NDTF debt securities 2,476 804 1,672 — — Other equity securities 112 112 — — — Other debt securities 324 92 232 — — Derivative assets 31 2 8 21 — Total assets 8,165 6,178 1,912 21 54 Derivative liabilities (353 ) (25 ) (217 ) (111 ) — Net assets (liabilities) $ 7,812 $ 6,153 $ 1,695 $ (90 ) $ 54 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 tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ (79 ) $ (97 ) $ (113 ) $ (114 ) Purchases, sales, issuances and settlements: Purchases — — 38 56 Settlements (9 ) (14 ) (32 ) (43 ) Total (losses) gains included on the Condensed Consolidated Balance Sheet (2 ) (5 ) 17 (15 ) Balance at end of period $ (90 ) $ (116 ) $ (90 ) $ (116 )
Quantitative Information Table - Level 3	The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. September 30, 2019 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 5 RTO auction pricing FTR price – per MWh $ 0.57 - $ 3.38 Duke Energy Indiana FTRs 16 RTO auction pricing FTR price – per MWh (0.52 ) - 6.85 Piedmont Natural gas contracts (111 ) Discounted cash flow Forward natural gas curves – price per MMBtu 1.85 - 2.99 Duke Energy Total Level 3 derivatives $ (90 ) 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. September 30, 2019 December 31, 2018 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy (a) $ 57,914 $ 63,276 $ 54,529 $ 54,534 Duke Energy Carolinas 11,758 13,462 10,939 11,471 Progress Energy 19,119 21,952 18,911 19,885 Duke Energy Progress 9,049 9,995 8,204 8,300 Duke Energy Florida 7,132 8,356 7,321 7,742 Duke Energy Ohio 2,719 3,096 2,165 2,239 Duke Energy Indiana 4,208 5,018 3,782 4,158 Piedmont 2,384 2,664 2,138 2,180 (a) Book value of long-term debt includes $1.5 billion as of September 30, 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 [Member]
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 Condensed Consolidated Balance Sheets. September 30, 2019 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 2,901 $ 2,847 $ — $ 54 NDTF debt securities 1,195 189 1,006 — Total assets 4,096 3,036 1,006 54 Derivative liabilities (67 ) — (67 ) — Net assets $ 4,029 $ 3,036 $ 939 $ 54 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 [Member]
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 Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,321 $ 2,321 $ — $ 1,991 $ 1,991 $ — NDTF debt securities 1,281 615 666 1,162 427 735 Other debt securities 101 49 52 64 17 47 Derivative assets 5 — 5 4 — 4 Total assets 3,708 2,985 723 3,221 2,435 786 Derivative liabilities (113 ) — (113 ) (44 ) — (44 ) Net assets $ 3,595 $ 2,985 $ 610 $ 3,177 $ 2,435 $ 742
Duke Energy Progress [Member]
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 Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,907 $ 1,907 $ — $ 1,588 $ 1,588 $ — NDTF debt securities 975 309 666 906 294 612 Other debt securities 2 2 — 6 6 — Derivative assets — — — 4 — 4 Total assets 2,884 2,218 666 2,504 1,888 616 Derivative liabilities (43 ) — (43 ) (27 ) — (27 ) Net assets $ 2,841 $ 2,218 $ 623 $ 2,477 $ 1,888 $ 589
Duke Energy Florida [Member]
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 Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 414 $ 414 $ — $ 403 $ 403 $ — NDTF debt securities 306 306 — 256 133 123 Other debt securities 56 4 52 48 1 47 Derivative assets 5 — 5 — — — Total assets 781 724 57 707 537 170 Derivative liabilities (54 ) — (54 ) (9 ) — (9 ) Net assets $ 727 $ 724 $ 3 $ 698 $ 537 $ 161
Duke Energy Ohio [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets were not material at September 30, 2019 , and December 31, 2018 .
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs
Duke Energy Indiana [Member]
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 Condensed Consolidated Balance Sheets. September 30, 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 $ 74 $ 74 $ — $ — $ 67 $ 67 $ — $ — Other debt securities 43 — 43 — 41 — 41 — Derivative assets 16 — — 16 23 1 — 22 Total assets $ 133 $ 74 $ 43 $ 16 $ 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) Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ 28 $ 44 $ 22 $ 27 Purchases, sales, issuances and settlements: Purchases — — 29 49 Settlements (7 ) (13 ) (26 ) (41 ) Total losses included on the Condensed Consolidated Balance Sheet (5 ) (2 ) (9 ) (6 ) Balance at end of period $ 16 $ 29 $ 16 $ 29
Piedmont Natural Gas [Member]
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 Condensed Consolidated Balance Sheets. September 30, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 3 Total Fair Value Level 1 Level 3 Derivative assets $ 2 $ 2 $ — $ 3 $ 3 $ — Derivative liabilities (111 ) — (111 ) (141 ) — (141 ) Net (liabilities) assets $ (109 ) $ 2 $ (111 ) $ (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) Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ (114 ) $ (150 ) $ (141 ) $ (142 ) Total gains (losses) and settlements 3 (3 ) 30 (11 ) Balance at end of period $ (111 ) $ (153 ) $ (111 ) $ (153 )

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2019
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [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 December 2020 December 2020 February 2021 April 2021 Credit facility amount $ 350 $ 475 $ 325 $ 250 Amounts borrowed at September 30, 2019 350 475 325 250 Amounts borrowed at December 31, 2018 325 450 300 225 Restricted Receivables at September 30, 2019 505 775 564 471 Restricted Receivables at December 31, 2018 564 699 547 357
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following tables summarize the impact of non-consolidated VIEs on the Condensed Consolidated Balance Sheets. September 30, 2019 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 48 $ 76 Investments in equity method unconsolidated affiliates 1,152 235 55 1,442 — — Total assets $ 1,152 $ 235 $ 55 $ 1,442 $ 48 $ 76 Taxes accrued (2 ) — — (2 ) — — Other current liabilities — — 3 3 — — Deferred income taxes 57 — — 57 — — Other noncurrent liabilities — — 11 11 — — Total liabilities $ 55 $ — $ 14 $ 69 $ — $ — Net assets $ 1,097 $ 235 $ 41 $ 1,373 $ 48 $ 76 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
DEFPF [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following table summarizes the impact of DEFPF on Duke Energy Florida's Condensed Consolidated Balance Sheets. (in millions) September 30, 2019 December 31, 2018 Receivables of VIEs $ 7 $ 5 Regulatory Assets: Current 52 52 Current Assets: Other 16 39 Other Noncurrent Assets: Regulatory assets 1,002 1,041 Current Liabilities: Other 2 10 Current maturities of long-term debt 54 53 Long-Term Debt 1,056 1,111
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The table below presents material balances reported on Duke Energy's Condensed Consolidated Balance Sheets related to Commercial Renewables VIEs. (in millions) September 30, 2019 December 31, 2018 Current Assets: Other $ 172 $ 123 Property, Plant and Equipment: Cost 5,160 4,007 Accumulated depreciation and amortization (996 ) (698 ) Other Noncurrent Assets: Other 63 261 Current maturities of long-term debt 177 174 Long-Term Debt 1,604 1,587 Other Noncurrent Liabilities: Asset retirement obligations 125 106 Other Noncurrent Liabilities: Other 218 212
Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 Receivables sold $ 217 $ 269 $ 326 $ 336 Less: Retained interests 48 93 76 118 Net receivables sold $ 169 $ 176 $ 250 $ 218 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, (in millions) 2019 2018 2019 2018 2019 2018 2019 2018 Sales Receivables sold $ 479 $ 450 $ 1,483 $ 1,478 $ 762 $ 754 $ 2,172 $ 2,140 Loss recognized on sale 4 4 11 10 4 5 13 12 Cash flows Cash proceeds from receivables sold $ 471 $ 449 $ 1,516 $ 1,499 $ 762 $ 743 $ 2,200 $ 2,140 Collection fees received — — 1 1 — — 1 1 Return received on retained interests 1 2 5 5 2 3 7 7
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [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 September 30, December 31, Entity Name Interest 2019 2018 ACP (a) 47 % $ 1,127 $ 797 Constitution 24 % 25 25 Total $ 1,152 $ 822 (a) Duke Energy evaluated this investment for impairment as of September 30, 2019 , and December 31, 2018 , and determined that fair value approximated carrying value and therefore no impairment was necessary.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	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) 2019 2020 2021 2022 2023 Thereafter Total Progress Energy $ 31 $ 121 $ 86 $ 81 $ 38 $ 41 $ 398 Duke Energy Progress 2 8 8 8 8 8 42 Duke Energy Florida 29 113 78 73 30 33 356 Duke Energy Indiana 2 10 5 — — — 17 Remaining Performance Obligations (in millions) 2019 2020 2021 2022 2023 Thereafter Total Piedmont $ 17 $ 69 $ 64 $ 64 $ 61 $ 430 $ 705
Disaggregation of Revenue	Disaggregated revenues are presented as follows: Three Months Ended September 30, 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 $ 2,923 $ 892 $ 1,522 $ 625 $ 897 $ 215 $ 294 $ — General 1,885 687 843 399 444 127 225 — Industrial 869 372 255 189 66 40 204 — Wholesale 617 113 429 368 61 13 63 — Other revenues 198 76 118 70 48 18 22 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 6,492 $ 2,140 $ 3,167 $ 1,651 $ 1,516 $ 413 $ 808 $ — Gas Utilities and Infrastructure Residential $ 113 $ — $ — $ — $ — $ 53 $ — $ 59 Commercial 68 — — — — 21 — 47 Industrial 26 — — — — 4 — 25 Power Generation — — — — — — — 13 Other revenues 16 — — — — 3 — 13 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 223 $ — $ — $ — $ — $ 81 $ — $ 157 Commercial Renewables Revenue from contracts with customers $ 69 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 8 $ — $ — $ — $ — $ — $ — $ — Total revenue from contracts with customers $ 6,792 $ 2,140 $ 3,167 $ 1,651 $ 1,516 $ 494 $ 808 $ 157 Other revenue sources (a) $ 148 $ 22 $ 75 $ 37 $ 32 $ (5 ) $ (1 ) $ 11 Total revenues $ 6,940 $ 2,162 $ 3,242 $ 1,688 $ 1,548 $ 489 $ 807 $ 168 (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. Three Months Ended September 30, 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 $ 2,729 $ 823 $ 1,425 $ 572 $ 853 $ 203 $ 279 $ — General 1,763 635 800 373 427 112 218 — Industrial 835 352 246 177 69 33 202 — Wholesale 589 132 372 335 37 3 81 — Other revenues 225 109 134 90 44 20 29 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 6,141 $ 2,051 $ 2,977 $ 1,547 $ 1,430 $ 371 $ 809 $ — Gas Utilities and Infrastructure Residential $ 116 $ — $ — $ — $ — $ 59 $ — $ 57 Commercial 66 — — — — 20 — 46 Industrial 28 — — — — 3 — 24 Power Generation — — — — — — — 13 Other revenues 23 — — — — 1 — 22 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 233 $ — $ — $ — $ — $ 83 $ — $ 162 Commercial Renewables Revenue from contracts with customers $ 61 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 16 $ — $ — $ — $ — $ 12 $ — $ — Total revenue from contracts with customers $ 6,451 $ 2,051 $ 2,977 $ 1,547 $ 1,430 $ 466 $ 809 $ 162 Other revenue sources (a) $ 177 $ 39 $ 68 $ 35 $ 32 $ 3 $ 10 $ 10 Total revenues $ 6,628 $ 2,090 $ 3,045 $ 1,582 $ 1,462 $ 469 $ 819 $ 172 (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. Nine Months Ended September 30, 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 $ 7,597 $ 2,331 $ 3,879 $ 1,657 $ 2,222 $ 563 $ 825 $ — General 4,896 1,714 2,225 1,044 1,181 335 619 — Industrial 2,339 927 708 514 194 109 595 — Wholesale 1,685 341 1,133 992 141 36 176 — Other revenues 557 222 389 239 150 59 66 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 17,074 $ 5,535 $ 8,334 $ 4,446 $ 3,888 $ 1,102 $ 2,281 $ — Gas Utilities and Infrastructure Residential $ 673 $ — $ — $ — $ — $ 229 $ — $ 443 Commercial 359 — — — — 96 — 263 Industrial 103 — — — — 14 — 91 Power Generation — — — — — — — 39 Other revenues 101 — — — — 13 — 88 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,236 $ — $ — $ — $ — $ 352 $ — $ 924 Commercial Renewables Revenue from contracts with customers $ 157 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 18 $ — $ — $ — $ — $ — $ — $ — Total Revenue from contracts with customers $ 18,485 $ 5,535 $ 8,334 $ 4,446 $ 3,888 $ 1,454 $ 2,281 $ 924 Other revenue sources (a) $ 491 $ 84 $ 224 $ 113 $ 99 $ (1 ) $ 8 $ 32 Total revenues $ 18,976 $ 5,619 $ 8,558 $ 4,559 $ 3,987 $ 1,453 $ 2,289 $ 956 (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. Nine Months Ended September 30, 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 $ 7,264 $ 2,263 $ 3,636 $ 1,540 $ 2,096 $ 564 $ 802 $ — General 4,619 1,608 2,109 972 1,137 318 584 — Industrial 2,235 893 678 481 197 96 567 — Wholesale 1,737 366 1,140 1,019 121 5 226 — Other revenues 558 261 359 222 137 57 66 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 16,413 $ 5,391 $ 7,922 $ 4,234 $ 3,688 $ 1,040 $ 2,245 $ — Gas Utilities and Infrastructure Residential $ 682 $ — $ — $ — $ — $ 236 $ — $ 446 Commercial 354 — — — — 97 — 257 Industrial 107 — — — — 13 — 93 Power Generation — — — — — — — 40 Other revenues 101 — — — — 13 — 88 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 1,244 $ — $ — $ — $ — $ 359 $ — $ 924 Commercial Renewables Revenue from contracts with customers $ 141 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 47 $ — $ — $ — $ — $ 36 $ — $ — Total Revenue from contracts with customers $ 17,845 $ 5,391 $ 7,922 $ 4,234 $ 3,688 $ 1,435 $ 2,245 $ 924 Other revenue sources (a) $ 561 $ 134 $ 197 $ 99 $ 92 $ 17 $ 43 $ 16 Total revenues $ 18,406 $ 5,525 $ 8,119 $ 4,333 $ 3,780 $ 1,452 $ 2,288 $ 940 (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 Condensed Consolidated Balance Sheets as shown in the following table. (in millions) September 30, 2019 December 31, 2018 Duke Energy $ 831 $ 896 Duke Energy Carolinas 312 313 Progress Energy 265 244 Duke Energy Progress 141 148 Duke Energy Florida 124 96 Duke Energy Ohio 2 2 Duke Energy Indiana 19 23 Piedmont 2 73 (in millions) September 30, 2019 December 31, 2018 Duke Energy Ohio $ 74 $ 86 Duke Energy Indiana 124 128

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 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. Three Months Ended September 30, Nine Months Ended September 30, (in millions, except per-share amounts) 2019 2018 2019 2018 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 1,324 $ 1,077 $ 3,041 $ 2,199 Weighted average common shares outstanding – basic 729 713 728 705 Equity Forwards — 1 — 1 Weighted average common shares outstanding – diluted 729 714 728 706 EPS from continuing operations attributable to Duke Energy common stockholders Basic $ 1.82 $ 1.51 $ 4.18 $ 3.12 Diluted $ 1.82 $ 1.51 $ 4.18 $ 3.11 Potentially dilutive items excluded from the calculation (a) 2 2 2 2 Dividends declared per common share $ 0.945 $ 0.9275 $ 2.800 $ 2.7075 Dividends declared on Series A preferred stock per depositary share $ 0.359 $ — $ 0.667 $ — (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables) - Qualified Pension Plan [Member]	9 Months Ended
	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Summary of Defined Benefit Plan Contributions	The following table includes information related to the Duke Energy Registrants' contributions to its qualified defined benefit pension plans. Nine Months Ended September 30, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Contributions made $ 77 $ 7 $ 57 $ 4 $ 53 $ 2 $ 2 $ 1
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended September 30, 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 $ 42 $ 13 $ 13 $ 7 $ 5 $ 1 $ 2 $ 1 Interest cost on projected benefit obligation 77 17 24 10 14 5 6 2 Expected return on plan assets (140 ) (36 ) (45 ) (22 ) (22 ) (7 ) (11 ) (5 ) Amortization of actuarial loss 28 6 10 4 6 2 3 2 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (2 ) Net periodic pension costs $ (1 ) $ (2 ) $ 1 $ (1 ) $ 3 $ 1 $ — $ (2 ) Three Months Ended September 30, 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 $ 47 $ 15 $ 13 $ 7 $ 5 $ 2 $ 2 $ 2 Interest cost on projected benefit obligation 74 18 24 10 13 4 6 3 Expected return on plan assets (140 ) (37 ) (45 ) (21 ) (23 ) (7 ) (10 ) (6 ) Amortization of actuarial loss 33 7 11 6 6 1 2 3 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (3 ) Net periodic pension costs $ 6 $ 1 $ 2 $ 2 $ 1 $ — $ — $ (1 ) Nine Months Ended September 30, 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 $ 116 $ 37 $ 34 $ 19 $ 15 $ 3 $ 6 $ 4 Interest cost on projected benefit obligation 242 58 76 34 41 14 19 8 Expected return on plan assets (426 ) (111 ) (134 ) (66 ) (66 ) (21 ) (32 ) (16 ) Amortization of actuarial loss 77 17 28 10 18 3 6 5 Amortization of prior service credit (24 ) (6 ) (2 ) (1 ) (1 ) — (1 ) (7 ) Net periodic pension costs $ (15 ) $ (5 ) $ 2 $ (4 ) $ 7 $ (1 ) $ (2 ) $ (6 ) Nine Months Ended September 30, 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 $ 137 $ 45 $ 39 $ 22 $ 16 $ 4 $ 7 $ 6 Interest cost on projected benefit obligation 224 54 70 31 38 13 18 9 Expected return on plan assets (420 ) (111 ) (133 ) (63 ) (69 ) (21 ) (31 ) (18 ) Amortization of actuarial loss 99 21 33 16 18 3 6 9 Amortization of prior service credit (24 ) (6 ) (3 ) (1 ) (1 ) — — (9 ) Net periodic pension costs $ 16 $ 3 $ 6 $ 5 $ 2 $ (1 ) $ — $ (3 )

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Summary of Effective Tax Rates	The ETRs from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Duke Energy 12.4 % 13.7 % 12.5 % 17.0 % Duke Energy Carolinas 16.7 % 22.6 % 17.7 % 22.3 % Progress Energy 15.3 % 18.8 % 16.2 % 17.0 % Duke Energy Progress 14.7 % 20.6 % 16.1 % 18.4 % Duke Energy Florida 16.5 % 15.0 % 18.0 % 16.3 % Duke Energy Ohio 12.9 % 16.0 % 15.2 % 16.0 % Duke Energy Indiana 23.2 % 22.7 % 23.7 % 24.7 % Piedmont 35.7 % 34.4 % 18.5 % 20.6 %

Organization and Basis of Pre_4

Organization and Basis of Presentation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Allocation of losses to noncontrolling interest	$ (19)	$ (16)	$ (110)	$ (12)
North Rosamond Solar Farm [Member]
Noncontrolling Interest [Line Items]
Allocation of losses to noncontrolling interest	12		86
Current Assets, Other [Member] | Piedmont Natural Gas [Member]
Noncontrolling Interest [Line Items]
Income taxes receivable	90		90		$ 11
Prepaid assets	$ 30		$ 30		$ 5

Organization and Basis of Pre_5

Organization and Basis of Presentation (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 379	$ 442
Other	163	141
Other Noncurrent Assets
Other	40	8
Total cash, cash equivalents and restricted cash	582	591	$ 449	$ 505
Progress Energy [Member]
Current Assets
Cash and cash equivalents	82	67
Other	16	39
Other Noncurrent Assets
Other	38	6
Total cash, cash equivalents and restricted cash	136	112	63	87
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	24	36
Other	16	39
Other Noncurrent Assets
Total cash, cash equivalents and restricted cash	$ 40	$ 75	$ 34	$ 53

Organization and Basis of Pre_6

Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Public Utilities, Inventory [Line Items]
Inventory	$ 3,107	$ 3,084
Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2,284	2,238
Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	490	491
Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	333	355
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Inventory	943	948
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	749	731
Duke Energy Carolinas [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	153	175
Duke Energy Carolinas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	41	42
Progress Energy [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,434	1,459
Progress Energy [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,056	1,049
Progress Energy [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	172	192
Progress Energy [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	206	218
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Inventory	939	954
Duke Energy Progress [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	710	734
Duke Energy Progress [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	118	106
Duke Energy Progress [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	111	114
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Inventory	495	504
Duke Energy Florida [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	346	315
Duke Energy Florida [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	54	86
Duke Energy Florida [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	95	103
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Inventory	128	126
Duke Energy Ohio [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	75	84
Duke Energy Ohio [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	12	14
Duke Energy Ohio [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	41	28
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Inventory	478	422
Duke Energy Indiana [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	325	312
Duke Energy Indiana [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	152	109
Duke Energy Indiana [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	1	1
Piedmont Natural Gas [Member]
Public Utilities, Inventory [Line Items]
Inventory	47	70
Piedmont Natural Gas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	4	2
Piedmont Natural Gas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	$ 43	$ 68

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	Sep. 06, 2019USD ($)asset	Sep. 30, 2019USD ($)		Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)segment		Sep. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Sale of noncontrolling interest	$ 465	$ (408)	[1]		$ (408)	[1]
Sale of noncontrolling interest, tax benefit	8
Pretax (gain) loss on disposal				$ (10)			$ 87
Operation, maintenance and other		1,484		1,584	4,337		4,592
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Pretax (gain) loss on disposal							106
Operation, maintenance and other		123		$ 76	$ 378		337
Number of reportable segments | segment					2
Beckjord [Member]
Segment Reporting Information [Line Items]
Pretax (gain) loss on disposal							(106)
Operation, maintenance and other							$ 1
Certain Renewable Assets [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Net proceeds from the sales of other assets	$ 415
Operating Wind, Solar and Battery Storage Assets [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Ownership percent divested	49.00%
Assets divested | asset	37
Operating Solar assets [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Ownership percent divested	33.00%
Assets divested | asset	11
Renewable Merchant Plants [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net		$ 160			$ 160
[1]	See Note 2 for additional discussion of the transaction.

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Income (Loss) From Discontinued Operations, net of tax		$ 4		$ (1)
Operating revenues	$ 6,940	6,628	$ 18,976	18,406
Segment income (loss)	1,327	1,078	3,047	2,203
Add back noncontrolling interests(b)	(19)	(16)	(110)	(12)
Add back preferred stock dividend	15		27
Net Income	1,323	1,066	2,964	2,190
Net income (attributable to parent)	1,327	1,082	3,047	2,202
Segment assets	155,917		155,917		$ 145,392
Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,569	6,253	17,357	16,783
Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	225	232	1,239	1,229
Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	138	127	362	347
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,932	6,612	18,958	18,359
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	16	18	47
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	1,451	1,122	3,375	2,649
Segment assets	151,998		151,998
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,577	6,260	17,381	16,806
Segment income (loss)	1,385	1,167	2,944	2,492
Segment assets	133,296		133,296
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	249	256	1,311	1,301
Segment income (loss)	26	17	292	161
Segment assets	13,424		13,424
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	138	127	362	347
Segment income (loss)	40	(62)	139	(4)
Segment assets	5,278		5,278
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,964	6,643	19,054	18,454
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(49)	(149)	(149)
Segment assets	185		185
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	7	24	23
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	24	24	72	72
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	32	31	96	95
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	17	18	53	54
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	(124)	(44)	(328)	(446)
Segment assets	3,734		3,734
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	25	34	71	101
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	489	469	1,453	1,452
Segment income (loss)	74	100	190	121
Net income (attributable to parent)	74	100	190	121
Segment assets	9,183		9,183		$ 8,555
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	408	373	1,099	1,055
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	81	84	354	361
Duke Energy Ohio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	489	457	1,453	1,416
Segment income (loss)	75	97	194	221
Segment assets	9,156		9,156
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	62	85	129	157
Segment assets	6,107		6,107
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	13	12	65	64
Segment assets	3,049		3,049
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment assets	(3)		(3)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues		12		36
Segment income (loss)	(1)	$ 3	(4)	$ (100)
Segment assets	$ 30		$ 30

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions	Oct. 31, 2019USD ($)	Oct. 30, 2019USD ($)	Oct. 11, 2019	Sep. 30, 2019USD ($)customer	Sep. 09, 2019USD ($)	Sep. 03, 2019USD ($)	Aug. 13, 2019USD ($)	Jul. 02, 2019USD ($)	Jun. 13, 2019USD ($)	May 29, 2019USD ($)	May 21, 2019USD ($)	Apr. 02, 2019USD ($)	Apr. 01, 2019USD ($)	Mar. 25, 2019USD ($)	Jan. 30, 2019USD ($)	Dec. 27, 2018USD ($)	Nov. 08, 2018USD ($)	Oct. 30, 2018USD ($)	Aug. 31, 2018USD ($)	Jul. 31, 2018USD ($)	Jun. 22, 2018USD ($)	May 31, 2018USD ($)	Apr. 13, 2018USD ($)	Feb. 28, 2018	Feb. 15, 2018USD ($)	Nov. 22, 2017	Sep. 27, 2017USD ($)	Sep. 26, 2017USD ($)	Aug. 25, 2017USD ($)	Jun. 01, 2017USD ($)	Jun. 30, 2016	Dec. 22, 2015	Jan. 05, 2015	Sep. 02, 2014	Sep. 30, 2019USD ($)customer	Nov. 30, 2018USD ($)	May 31, 2018USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2019USD ($)customer	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Sep. 30, 2019USD ($)customerMW	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Aug. 16, 2019USD ($)	Jul. 12, 2019USD ($)	Apr. 30, 2019USD ($)	Mar. 28, 2019USD ($)	Jan. 28, 2019USD ($)	Oct. 31, 2018customer	Sep. 28, 2018USD ($)	Sep. 30, 2017customer	Oct. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								$ 1,484		$ 1,584		$ 4,337	$ 4,592
Loss before income taxes																																								(1,511)		(1,230)		(3,388)	(2,640)
Generation facilities to be retired, net				$ 267																															$ 267					267	$ 362			267
Public utilities, property, plant and equipment, net				98,912																															98,912					98,912	91,694			98,912
Regulated operating revenue, electric, non-nuclear																																								6,515		6,216		17,223	16,678
Impairment charges																																								(20)		124		$ (16)	339
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW																																												5,002
Public utilities, property, plant and equipment, net				3,193																															3,193					3,193				$ 3,193
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																																		47.00%
Long-term purchase commitment, period																																		20 years
Investment amount				$ 1,100																															$ 1,100					$ 1,100				$ 1,100
Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage				24.00%																															24.00%					24.00%				24.00%
Estimated contributions				$ 229																															$ 229					$ 229				$ 229
Equity method investment, OTTI																																													55
Dominion Resources [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																																		48.00%
Southern Company Gas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																																		5.00%
Williams Partners L.P. [Member] | Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage				41.00%																															41.00%					41.00%				41.00%
Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost				$ 7,300																															$ 7,300					$ 7,300				$ 7,300
Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost				$ 7,800																															$ 7,800					$ 7,800				$ 7,800
Hurricane Florence, Hurricane Michael And Winter Storm Diego Damages [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other												$ 553
Estimated capital cost												96
Credit Facility [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Percentage of outstanding borrowings				47.00%																															47.00%					47.00%				47.00%
Atlantic Coast Pipeline [Member] | Financial Guarantee [Member]
Public Utilities, General Disclosures [Line Items]
Maximum potential amount of future payments associated with guarantees				$ 802																															$ 802					$ 802				$ 802
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								443		514		1,324	1,464
Loss before income taxes																																								(708)		(641)		(1,439)	(1,204)
Public utilities, property, plant and equipment, net				31,456																															31,456					31,456	29,245			31,456
Impairment charges																																								6		1		11	191
Duke Energy Carolinas [Member] | Generation Facilities Evaluated For Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net				732																															732					732				732
Duke Energy Carolinas [Member] | Hurricane Florence, Hurricane Michael And Winter Storm Diego Damages [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other												171
Estimated capital cost												20
Duke Energy Carolinas [Member] | 2017 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																											$ 4
Utilities operating expense																					$ 150
Penalty assessed																					70
Reduction of annual recovery of deferred coal ash costs																					$ 14
Requested rate increase (decrease), amount																													$ 647
Requested rate increase, percentage																													13.60%
Requested return on equity, percent																								9.90%
Public utilities, requested equity capital structure, percentage																								52.00%
Public utilities, requested debt capital structure, percentage																								48.00%
Regulatory asset, amortization period																					5 years
Loss before income taxes																																											14
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																	$ 168
Requested rate increase, percentage																	10.00%
Public utilities, approved equity capital structure, percentage											53.00%
Public utilities, approved debt capital structure, percentage											47.00%
Approved return on equity percentage											9.50%
Change in tax rate, deferred tax liability, income tax benefit											$ 66						$ 66
Measurement period adjustment, income tax expense (benefit)											45						46
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Recovery costs denied											115
Regulatory assets											$ 96						$ 242
Regulatory asset, amortization period											5 years						5 years
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member] | Deferred Project Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets											$ 125
Regulatory asset, amortization period											12 years
Duke Energy Carolinas [Member] | FERC Formula Rate Matter [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Customer refundable fees, refund payments																									$ 25
Duke Energy Carolinas [Member] | 2018 Sale of Hydro Plants [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																															$ 32
Estimated loss on asset sale																																					$ 40
Duke Energy Carolinas [Member] | 2019 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				$ 291
Requested rate increase, percentage				6.00%
Requested rate increase (decrease), gross amount				$ 445
Requested rate increase (decrease), rider reduction				154
Duke Energy Carolinas [Member] | State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
State and local taxes, increase (reduction), amount											$ (17)						$ (17)
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								378		431		1,070	1,187
Loss before income taxes																																								(326)		(272)		(775)	(652)
Generation facilities to be retired, net				267																															267					267	362			267
Public utilities, property, plant and equipment, net				22,100																															22,100					22,100	20,398			22,100
Impairment charges																																													33
Duke Energy Progress [Member] | Generation Facilities Evaluated For Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net				1,200																															1,200					1,200				$ 1,200
Duke Energy Progress [Member] | Asheville Plant [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW																																												376
Generation facilities to be retired, net				234																															234					234	327			$ 234
Duke Energy Progress [Member] | Hurricane Florence, Hurricane Michael And Winter Storm Diego Damages [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other												382
Estimated capital cost												$ 76
Duke Energy Progress [Member] | 2017 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																														$ 477
Requested rate increase, percentage																														14.90%
Requested return on equity, percent																										9.90%
Public utilities, requested equity capital structure, percentage																										52.00%
Public utilities, requested debt capital structure, percentage																										48.00%
Requested rate increase (decrease), amended amount																														$ 420
Requested rate increase (decrease) amended, percentage																														13.00%
Loss before income taxes																																											$ 68
Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																	$ 59
Requested rate increase, percentage																	10.30%
Public utilities, approved equity capital structure, percentage											53.00%
Public utilities, approved debt capital structure, percentage											47.00%
Approved return on equity percentage											9.50%
Change in tax rate, deferred tax liability, income tax benefit											$ 17						$ 17
Measurement period adjustment, income tax expense (benefit)											12						10
Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Recovery costs denied											65
Regulatory assets											$ 4						$ 51
Regulatory asset, amortization period											5 years						5 years
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																																																		$ 893
Regulatory asset, amortization period																																												10 years
Duke Energy Progress [Member] | Hurricane Dorian Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - O&M				208																															208					208				$ 208
Estimated storm costs - capital investments				10																															10					10				10
Duke Energy Progress [Member] | Hurricane Dorian Storm Damage [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				$ 182																															$ 182					$ 182				$ 182
Duke Energy Progress [Member] | State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
State and local taxes, increase (reduction), amount											$ 12						$ 12
Duke Energy Progress [Member] | Subsequent Event [Member] | FERC Complaint [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Agreement return on equity			11.00%
Duke Energy Progress [Member] | Subsequent Event [Member] | 2019 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount		$ 464
Requested rate increase, percentage		12.30%
Requested rate increase (decrease), gross amount		$ 586
Requested rate increase (decrease), rider reduction		120
Requested rate increase (decrease), rider reduction, TCJA and return deferred revenue		$ 122
Duke Energy Progress [Member] | North Carolina [Member] | Hurricane Dorian Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer				270,000																															270,000					270,000				270,000
Duke Energy Progress [Member] | South Carolina [Member] | Hurricane Dorian Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer				30,000																															30,000					30,000				30,000
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								$ 256		245		$ 730	719
Loss before income taxes																																								(346)		(286)		(715)	(614)
Public utilities, property, plant and equipment, net				$ 14,739																															$ 14,739					14,739	13,824			14,739
Impairment charges																																								(25)		1		(25)	1
Duke Energy Florida [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				80																															80					80	217			80
Duke Energy Florida [Member] | Citrus County Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital costs																																									1,600														$ 1,500
Impairment charges																																									60
Reversal of impairment charges																																			25
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer																																																						1,000,000
Operation, maintenance and other									$ 6
Decrease in storm reserve									24
Allowed storm reserve																						$ 132															132
Property, plant and equipment, net									$ 18
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - capital and operation maintenance																						510															510														$ 508
Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer																																																				72,000
Estimated storm costs - capital and operation maintenance				360																															360					360				360					$ 221
Property, plant and equipment, net				85																															85					85	35			85
Duke Energy Florida [Member] | Hurricane Dorian Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - capital and operation maintenance				153																															153					153				153
Duke Energy Florida [Member] | Federal Tax Act Impacts [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Tax act annual savings																$ 4						134
Tax act excess deferred tax amortization requested rate decrease, amount																71						67
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																						201
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | FPSC [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																$ 155						151															151
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | Crystal River Units 3 and 4 [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net																						$ 50															$ 50
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Hamilton Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount																		$ 15
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Columbia Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																				$ 14
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Trenton Generation Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount														$ 13
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Lake Placid Generation Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount														8
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | DeBary Solar Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount														$ 11
Duke Energy Florida [Member] | Noncurrent Assets, Other [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - capital and operation maintenance				220																															220					220	165			220
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								123		76		378	337
Loss before income taxes																																								(85)		(119)		(224)	(144)
Public utilities, property, plant and equipment, net				7,208																															7,208					7,208	6,643			7,208
Regulated operating revenue, electric, non-nuclear																																								408		373		1,099	1,055
Duke Energy Ohio [Member] | Ohio Base Rate Case 2017 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																																						$ 15
Requested return on equity, percent																																						10.40%
Public utilities, requested equity capital structure, percentage																							50.75%
Public utilities, requested debt capital structure, percentage																							49.25%
Approved rate increase (decrease), amount																							$ (20)
Requested rate increase (decrease), amended amount																							$ (19)
Requested rate increase (decrease) amended, percentage																							9.84%
Duke Energy Ohio [Member] | Ohio Base Rate Case 2017 [Member] | PUCO [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																												$ (18)
Requested return on equity, percent																												9.22%
Duke Energy Ohio [Member] | Ohio Base Rate Case 2017 [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																												$ (29)
Requested return on equity, percent																												10.24%
Requested Rider Revenue Increase																							$ 10
Duke Energy Ohio [Member] | Energy Efficiency Cost Recovery [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulated operating revenue, electric, non-nuclear																																							$ 20
Duke Energy Ohio [Member] | Energy Efficiency Cost Recovery [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount																											$ 38
Approved rate increase (decrease), one-time waiver amount																																														$ 56
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | OPSB [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost excluding AFUDC				163																															163					163				163
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | OPSB [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost excluding AFUDC				245																															245					245				245
Duke Energy Ohio [Member] | MGP Cost Recovery - 2009 Through 2012 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				55																															55					55				55
Duke Energy Ohio [Member] | MGP Cost Recovery - 2013 Through 2017 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																																					$ 26
Duke Energy Ohio [Member] | MGP Cost Recovery - 2013 Through 2017 [Member] | PUCO [Member] | MGP Costs - Regulatory Disallowance [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																																					$ 12
Duke Energy Ohio [Member] | MGP Cost Recovery - 2018 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				20																															20					20				20
Duke Energy Ohio [Member] | MGP Cost Recovery - 2018 [Member] | PUCO [Member] | MGP Costs - Regulatory Disallowance [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																																$ 11
Duke Energy Kentucky [Member] | Duke Energy Kentucky Gas Base Rate Case [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																			$ 11
Requested rate increase, percentage																			11.10%
Approved rate increase (decrease), amount															$ 7
Requested rate increase (decrease), amended amount																			$ (5)
Approved return on equity percentage															9.70%
Duke Energy Kentucky [Member] | Duke Energy Kentucky Electric Base Rate Case [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						$ 46
Requested rate increase, percentage						12.50%
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								192		198		569	576
Loss before income taxes																																								(203)		(154)		(476)	(421)
Public utilities, property, plant and equipment, net				10,937																															10,937					10,937	10,529			$ 10,937
Impairment charges																																										30			30
Duke Energy Indiana [Member] | 2019 Indiana Rate Case [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					$ 395			$ 395
Requested rate increase, percentage								15.00%
Requested rate increase, percentage, net of tax								17.00%
Rate base																																									10,200
Requested rate increase (decrease), amended amount					393
Amount reduced from initial request					$ 2
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage																																												12.38%
Approved return on equity percentage adder																																	0.50%
Duke Energy Indiana [Member] | FERC Complaint [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Requested return on equity, percent																																												8.67%
Duke Energy Indiana [Member] | FERC Complaint 1 [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage																																10.32%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Requested return on equity, percent																															9.70%
Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																								78		85		$ 241	252
Loss before income taxes																																								28		$ 32		(119)	$ (102)
Public utilities, property, plant and equipment, net				$ 6,582																															$ 6,582					$ 6,582	$ 5,911			$ 6,582
Piedmont Natural Gas [Member] | North Carolina Integrity Management Rider Filing [Member] | TPUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount										$ 9
Piedmont Natural Gas [Member] | Tennessee Integrity Management Rider Filing November 2018 [Member] | TPUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount																																				$ 3
Piedmont Natural Gas [Member] | 2019 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							$ 83						$ 83
Requested rate increase, percentage													9.00%
Requested rate increase (decrease), gross amount							$ 109
Requested return on equity, percent							9.70%
Public utilities, requested equity capital structure, percentage							52.00%
Public utilities, requested debt capital structure, percentage							48.00%
Change in tax rate, deferred tax liability, income tax benefit							$ 37
Measurement period adjustment, income tax expense (benefit)							23
Piedmont Natural Gas [Member] | 2019 North Carolina Rate Case [Member] | NCUC [Member] | Distribution Integrity Management Program [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets							11
Piedmont Natural Gas [Member] | State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | 2019 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
State and local taxes, increase (reduction), amount							$ (21)
Piedmont Natural Gas [Member] | Subsequent Event [Member] | North Carolina Integrity Management Rider Filing [Member] | TPUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 11

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)MW	Dec. 31, 2018USD ($)
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	$ 98,912	$ 91,694
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	31,456	29,245
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	$ 10,937	$ 10,529
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	5,002
Public utilities, property, plant and equipment, net	$ 3,193
Allen Steam Station Units 1-3 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	585
Public utilities, property, plant and equipment, net	$ 154
Gallagher Units 2 and 4 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Public utilities, property, plant and equipment, net	$ 116
Gibson Units 1-5 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	3,132
Public utilities, property, plant and equipment, net	$ 1,949
Cayuga Units 1-2 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,005
Public utilities, property, plant and equipment, net	$ 974

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Details) $ in Millions	Jun. 18, 2018USD ($)	Sep. 30, 2019USD ($)plantclaim	Sep. 30, 2019USD ($)plantclaim	Dec. 31, 2018USD ($)	Dec. 31, 2016plant
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual		$ 62	$ 62	$ 65
Coal Ash Insurance Coverage Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Number of NC and SC plants with ash basins | plant		15	15
NCDEQ State Enforcement Actions [Member]
Valuation and Qualifying Accounts [Abstract]
Number of plants with no disputed facts | plant					7
Number of NC plants with ash basins | plant					14
Number of plants with disputed facts | plant					7
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual		$ 8	$ 8	9
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves		592	592	630
Reinsurance retention policy, excess retention, amount reinsured			747
Probable insurance recoveries		$ 722	$ 722	739
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member] | Non-Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim		121	121
Asbestos-related injuries and damages reserves		$ 32	$ 32
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim		40	40
Asbestos-related injuries and damages reserves		$ 13	$ 13
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual		52	52	54
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual		13	13	12
Duke Energy Progress [Member] | Spent Nuclear Fuel Matters [Member]
Valuation and Qualifying Accounts [Abstract]
Pending litigation, damages sought	$ 100
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual		22	22	$ 24
Duke Energy Florida [Member] | Spent Nuclear Fuel Matters [Member]
Valuation and Qualifying Accounts [Abstract]
Pending litigation, damages sought	$ 203
Fluor Letter Of Credit [Member] | Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Drawings on credit facility			$ 67
Citrus County Station [Member] | Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Reversal of impairment charges		$ 25

Commitments and Contingencies_3

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	$ 77	$ 81
Provisions/adjustments	30	7
Cash reductions	(35)	(20)
Balance at end of period	72	68
Environmental exit costs, reasonably possible additional loss	49
Duke Energy Carolinas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	11	10
Provisions/adjustments	4	3
Cash reductions	(4)	(2)
Balance at end of period	11	11
Environmental exit costs, reasonably possible additional loss	11
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	11	15
Provisions/adjustments	9	2
Cash reductions	(3)	(5)
Balance at end of period	17	12
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	4	3
Provisions/adjustments	3	3
Cash reductions	(2)	(1)
Balance at end of period	5	5
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	6	12
Provisions/adjustments	5	(1)
Cash reductions	(1)	(4)
Balance at end of period	10	7
Duke Energy Ohio [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	48	47
Provisions/adjustments	10	3
Cash reductions	(28)	(12)
Balance at end of period	30	38
Environmental exit costs, reasonably possible additional loss	31
Duke Energy Indiana [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	5	5
Provisions/adjustments		1
Cash reductions	0	(1)
Balance at end of period	5	5
Piedmont Natural Gas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	2	2
Provisions/adjustments	6
Cash reductions	0
Balance at end of period	8	$ 2
Environmental exit costs, reasonably possible additional loss	$ 2

Commitments and Contingencies_4

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Reserves for legal matters	$ 62	$ 65
Duke Energy Carolinas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	8	9
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	52	54
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	13	12
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	22	24
Piedmont Natural Gas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$ 1	$ 1

Leases (Operating Lease Right-o

Leases (Operating Lease Right-of-use Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
ROU assets	$ 1,703	$ 1,750
Operating lease liabilities – current	212	205
Operating lease liabilities – noncurrent	1,456	1,504
Duke Energy Carolinas [Member]
Lessee, Lease, Description [Line Items]
ROU assets	135	153
Operating lease liabilities – current	27	28
Operating lease liabilities – noncurrent	108	127
Progress Energy [Member]
Lessee, Lease, Description [Line Items]
ROU assets	814	863
Operating lease liabilities – current	99	96
Operating lease liabilities – noncurrent	710	766
Duke Energy Progress [Member]
Lessee, Lease, Description [Line Items]
ROU assets	397	407
Operating lease liabilities – current	36	35
Operating lease liabilities – noncurrent	360	371
Duke Energy Florida [Member]
Lessee, Lease, Description [Line Items]
ROU assets	417	456
Operating lease liabilities – current	63	61
Operating lease liabilities – noncurrent	350	395
Duke Energy Ohio [Member]
Lessee, Lease, Description [Line Items]
ROU assets	22	23
Operating lease liabilities – current	1	1
Operating lease liabilities – noncurrent	21	22
Duke Energy Indiana [Member]
Lessee, Lease, Description [Line Items]
ROU assets	58	61
Operating lease liabilities – current	3	4
Operating lease liabilities – noncurrent	55	58
Piedmont Natural Gas [Member]
Lessee, Lease, Description [Line Items]
ROU assets	25	26
Operating lease liabilities – current	4	4
Operating lease liabilities – noncurrent	$ 24	$ 25

Leases (Lease Costs) (Details)

Leases (Lease Costs) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		$ 221
Operating lease expense	$ 75	220
Short-term lease expense	2	15
Variable lease expense	27	48
Finance lease expense
Amortization of leased assets	28	84
Interest on lease liabilities	7	44
Total finance lease expense	35	128
Total lease expense	139	411
Operating cash flows from finance leases		44
Financing cash flows from finance leases		84
Finance		175
Operating, lease assets obtained		147
Duke Energy Carolinas [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		26
Operating lease expense	13	36
Short-term lease expense		4
Variable lease expense	6	18
Finance lease expense
Amortization of leased assets	2	4
Interest on lease liabilities	3	10
Total finance lease expense	5	14
Total lease expense	24	72
Operating cash flows from finance leases		10
Financing cash flows from finance leases		4
Operating, lease assets obtained		44
Progress Energy [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		104
Operating lease expense	39	121
Short-term lease expense		7
Variable lease expense	22	29
Finance lease expense
Amortization of leased assets	9	17
Interest on lease liabilities	12	31
Total finance lease expense	21	48
Total lease expense	82	205
Operating cash flows from finance leases		31
Financing cash flows from finance leases		17
Finance		175
Operating, lease assets obtained		30
Duke Energy Progress [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		43
Operating lease expense	16	52
Short-term lease expense		3
Variable lease expense	21	24
Finance lease expense
Amortization of leased assets	1	3
Interest on lease liabilities	10	24
Total finance lease expense	11	27
Total lease expense	48	106
Operating cash flows from finance leases		24
Financing cash flows from finance leases		3
Finance		175
Operating, lease assets obtained		30
Duke Energy Florida [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		61
Operating lease expense	23	69
Short-term lease expense		4
Variable lease expense	1	5
Finance lease expense
Amortization of leased assets	8	14
Interest on lease liabilities	2	7
Total finance lease expense	10	21
Total lease expense	34	99
Operating cash flows from finance leases		7
Financing cash flows from finance leases		14
Duke Energy Ohio [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		1
Operating lease expense	3	9
Short-term lease expense		1
Finance lease expense
Amortization of leased assets		1
Total finance lease expense		1
Total lease expense	3	11
Financing cash flows from finance leases		1
Duke Energy Indiana [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		5
Operating lease expense	5	15
Short-term lease expense	1	2
Finance lease expense
Interest on lease liabilities		1
Total finance lease expense		1
Total lease expense	6	18
Operating cash flows from finance leases		1
Piedmont Natural Gas [Member]
Lessee, Lease, Description [Line Items]
Operating cash flows from operating leases		6
Operating lease expense	1	4
Finance lease expense
Total lease expense	$ 1	4
Operating, lease assets obtained		$ 1

Leases (Rent Expense) (Details)

Leases (Rent Expense) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Operating Leased Assets [Line Items]
Rent expense	$ 268
Duke Energy Carolinas [Member]
Operating Leased Assets [Line Items]
Rent expense	49
Progress Energy [Member]
Operating Leased Assets [Line Items]
Rent expense	143
Duke Energy Progress [Member]
Operating Leased Assets [Line Items]
Rent expense	75
Duke Energy Florida [Member]
Operating Leased Assets [Line Items]
Rent expense	68
Duke Energy Ohio [Member]
Operating Leased Assets [Line Items]
Rent expense	13
Duke Energy Indiana [Member]
Operating Leased Assets [Line Items]
Rent expense	21
Piedmont Natural Gas [Member]
Operating Leased Assets [Line Items]
Rent expense	$ 11

Leases (Operating Lease Maturit

Leases (Operating Lease Maturities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due (Topic 842)
2020	$ 278
2021	220
2022	201
2023	192
2024	179
Thereafter	1,008
Total operating lease payments	2,078
Less: present value discount	(410)
Total operating lease liabilities	1,668
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	32
2021	20
2022	19
2023	18
2024	14
Thereafter	60
Total operating lease payments	163
Less: present value discount	(28)
Total operating lease liabilities	135
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	129
2021	100
2022	95
2023	95
2024	95
Thereafter	480
Total operating lease payments	994
Less: present value discount	(185)
Total operating lease liabilities	809
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	51
2021	45
2022	40
2023	41
2024	41
Thereafter	291
Total operating lease payments	509
Less: present value discount	(113)
Total operating lease liabilities	396
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	78
2021	55
2022	55
2023	54
2024	54
Thereafter	189
Total operating lease payments	485
Less: present value discount	(72)
Total operating lease liabilities	413
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	2
2021	2
2022	2
2023	2
2024	2
Thereafter	22
Total operating lease payments	32
Less: present value discount	(10)
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	6
2021	4
2022	4
2023	4
2024	4
Thereafter	63
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 Natural Gas [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	5
2021	5
2022	5
2023	5
2024	5
Thereafter	6
Total operating lease payments	31
Less: present value discount	(3)
Total operating lease liabilities	$ 28
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	Sep. 30, 2019	Dec. 31, 2018
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	$ 179
2021	184
2022	177
2023	173
2024	149
Thereafter	827
Total finance lease payments	1,689
Less: amounts representing interest	(699)
Total finance lease liabilities	990
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 [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	19
2021	16
2022	14
2023	14
2024	14
Thereafter	189
Total finance lease payments	266
Less: amounts representing interest	(160)
Total finance lease liabilities	106
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 [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	69
2021	69
2022	69
2023	69
2024	57
Thereafter	552
Total finance lease payments	885
Less: amounts representing interest	(477)
Total finance lease liabilities	408
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 [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	44
2021	44
2022	44
2023	44
2024	44
Thereafter	539
Total finance lease payments	759
Less: amounts representing interest	(451)
Total finance lease liabilities	308
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 [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	25
2021	25
2022	25
2023	25
2024	13
Thereafter	13
Total finance lease payments	126
Less: amounts representing interest	(26)
Total finance lease liabilities	100
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 [Member]
Finance Lease Liabilities, Payments Due (Topic 840)
2019		2
Minimum annual payments		2
Total		2
Duke Energy Indiana [Member]
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	9 Months Ended
	Sep. 30, 2019	Jan. 01, 2019
Assets
Operating	$ 1,703	$ 1,750
Finance	952
Total lease assets	2,655
Current
Operating	212	205
Finance	117
Noncurrent
Operating	1,456	1,504
Finance	873
Total lease liabilities	2,658
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	221
Operating cash flows from finance leases	44
Financing cash flows from finance leases	84
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	147
Finance	$ 175
Weighted-average remaining lease term (years)
Operating leases	11 years
Finance leases	13 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	8.00%
Duke Energy Carolinas [Member]
Assets
Operating	$ 135	153
Finance	125
Total lease assets	260
Current
Operating	27	28
Finance	6
Noncurrent
Operating	108	127
Finance	100
Total lease liabilities	241
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	26
Operating cash flows from finance leases	10
Financing cash flows from finance leases	4
Lease assets obtained in exchange for new lease liabilities (non-cash)
Operating, lease assets obtained	$ 44
Weighted-average remaining lease term (years)
Operating leases	9 years
Finance leases	18 years
Weighted-average discount rate
Operating leases	3.50%
Finance leases	12.90%
Progress Energy [Member]
Assets
Operating	$ 814	863
Finance	448
Total lease assets	1,262
Current
Operating	99	96
Finance	23
Noncurrent
Operating	710	766
Finance	385
Total lease liabilities	1,217
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	104
Operating cash flows from finance leases	31
Financing cash flows from finance leases	17
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	11.80%
Duke Energy Progress [Member]
Assets
Operating	$ 397	407
Finance	309
Total lease assets	706
Current
Operating	36	35
Finance	6
Noncurrent
Operating	360	371
Finance	302
Total lease liabilities	704
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	43
Operating cash flows from finance leases	24
Financing cash flows from finance leases	3
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 [Member]
Assets
Operating	$ 417	456
Finance	139
Total lease assets	556
Current
Operating	63	61
Finance	17
Noncurrent
Operating	350	395
Finance	83
Total lease liabilities	513
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	61
Operating cash flows from finance leases	7
Financing cash flows from finance leases	$ 14
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 [Member]
Assets
Operating	$ 22	23
Total lease assets	22
Current
Operating	1	1
Noncurrent
Operating	21	22
Total lease liabilities	22
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	1
Financing cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	18 years
Finance leases	0 years
Weighted-average discount rate
Operating leases	4.30%
Duke Energy Indiana [Member]
Assets
Operating	$ 58	61
Finance	10
Total lease assets	68
Current
Operating	3	4
Noncurrent
Operating	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	5
Operating cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	18 years
Finance leases	27 years
Weighted-average discount rate
Operating leases	4.10%
Finance leases	11.90%
Piedmont Natural Gas [Member]
Assets
Operating	$ 25	26
Total lease assets	25
Current
Operating	4	4
Noncurrent
Operating	24	$ 25
Total lease liabilities	28
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	6
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
Finance leases	0 years
Weighted-average discount rate
Operating leases	3.60%

Leases (Narrative) (Details)

Leases (Narrative) (Details) - Renewable Energy Projects [Member] $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Contingent lease payments	$ 69	$ 205
Operating lease assets, cost basis	3,347	3,347
Operating lease assets, accumulated depreciation	$ 692	$ 692

Debt and Credit Facilities (Nar

Debt and Credit Facilities (Narrative) (Details) - USD ($)	1 Months Ended
	May 31, 2019	Sep. 30, 2019
Debt Instrument [Line Items]
Debt issuances		$ 5,310,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		8,000,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances		800,000,000
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		1,750,000,000
Duke Energy Carolinas [Member] | USDOJ [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum master credit facility balance required		250,000,000
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances		600,000,000
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		1,250,000,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Debt	$ 600,000,000
Debt issuances		600,000,000
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		$ 500,000,000
Term Loan [Member] | Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 350,000,000

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Debt issuances	$ 5,310,000,000
Repayments of long-term debt	2,737,000,000	$ 2,278,000,000
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances	1,800,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances	800,000,000
Repayments of long-term debt	5,000,000	704,000,000
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances	600,000,000
Repayments of long-term debt	603,000,000	2,000,000
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	210,000,000	717,000,000
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances	1,010,000,000
Repayments of long-term debt	451,000,000	3,000,000
Duke Energy Ohio [Member] | April 2019 First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	450,000,000
Duke Energy Ohio [Member] | Debentures Due October 2019 [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	100,000,000
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Debt issuances	500,000,000
Repayments of long-term debt	60,000,000	$ 1,000,000
Duke Energy Indiana [Member] | Pollution Control Bonds [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	150,000,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Debt issuances	600,000,000
Repayments of long-term debt	350,000,000
Piedmont Natural Gas [Member] | Senior Unsecured Term Loan Facility Due September 2019 [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	350,000,000
Unsecured Debt [Member] | March 2019 Debt Issuance 3.250% Coupon Due 2022 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 300,000,000
Interest rate	2.788%
Unsecured Debt [Member] | March 2019 Debt Issuance 3.227% Coupon Due 2022 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 300,000,000
Interest rate	3.227%
Unsecured Debt [Member] | May 2019 Debt Issuance 3.500% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600,000,000
Interest rate	3.50%
Unsecured Debt [Member] | June 2019 Debt Issuance 3.400% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600,000,000
Interest rate	3.40%
Unsecured Debt [Member] | June 2019 Debt Issuance 4.200% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600,000,000
Interest rate	4.20%
Unsecured Debt [Member] | July 2019 Debt Issuance 4.320% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 40,000,000
Interest rate	4.32%
Unsecured Debt [Member] | September 2019 Debt Issuance 3.230% Coupon Due 2025 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 95,000,000
Interest rate	3.23%
Unsecured Debt [Member] | September 2019 Debt Issuance 3.560% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 75,000,000
Interest rate	3.56%
Unsecured Debt [Member] | Parent Company [Member] | March 2019 Debt Issuance 3.250% Coupon Due 2022 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 300,000,000
Unsecured Debt [Member] | Parent Company [Member] | March 2019 Debt Issuance 3.227% Coupon Due 2022 [Member]
Debt Instrument [Line Items]
Debt issuances	300,000,000
Unsecured Debt [Member] | Parent Company [Member] | June 2019 Debt Issuance 3.400% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	600,000,000
Unsecured Debt [Member] | Parent Company [Member] | June 2019 Debt Issuance 4.200% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	600,000,000
Unsecured Debt [Member] | Duke Energy Ohio [Member] | July 2019 Debt Issuance 4.320% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	40,000,000
Unsecured Debt [Member] | Duke Energy Ohio [Member] | September 2019 Debt Issuance 3.230% Coupon Due 2025 [Member]
Debt Instrument [Line Items]
Debt issuances	95,000,000
Unsecured Debt [Member] | Duke Energy Ohio [Member] | September 2019 Debt Issuance 3.560% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	75,000,000
Unsecured Debt [Member] | Piedmont Natural Gas [Member] | May 2019 Debt Issuance 3.500% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	600,000,000
First Mortgage [Member] | January 2019 Debt Issuance 3.650% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 400,000,000
Interest rate	3.65%
First Mortgage [Member] | January 2019 Debt Issuance 4.300% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 400,000,000
Interest rate	4.30%
First Mortgage [Member] | March 2019 Debt Issuance 3.450% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600,000,000
Interest rate	3.45%
First Mortgage [Member] | August 2019 Debt Issuance 2.450% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 450,000,000
Interest rate	2.45%
First Mortgage [Member] | August 2019 Debt Issuance 3.200% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 350,000,000
Interest rate	3.20%
First Mortgage [Member] | September 2019 Debt Issuance 3.250% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500,000,000
Interest rate	3.25%
First Mortgage [Member] | Duke Energy Carolinas [Member] | August 2019 Debt Issuance 2.450% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 450,000,000
First Mortgage [Member] | Duke Energy Carolinas [Member] | August 2019 Debt Issuance 3.200% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	350,000,000
First Mortgage [Member] | Duke Energy Progress [Member] | March 2019 Debt Issuance 3.450% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	600,000,000
First Mortgage [Member] | Duke Energy Ohio [Member] | January 2019 Debt Issuance 3.650% Coupon Due 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	400,000,000
First Mortgage [Member] | Duke Energy Ohio [Member] | January 2019 Debt Issuance 4.300% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	400,000,000
First Mortgage [Member] | Duke Energy Indiana [Member] | September 2019 Debt Issuance 3.250% Coupon Due 2049 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500,000,000

Debt and Credit Facilities (S_2

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 3,096	$ 3,406
Other debt obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	566
Parent Company [Member] | Unsecured Debt [Member] | Debt Maturing September 2019, 5.050% Coupon [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 500
Parent Company [Member] | Unsecured Debt [Member] | Debt Maturing June 2020, 2.100% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	2.10%
Current maturities of long-term debt	$ 330
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt		350
Duke Energy Kentucky [Member] | Secured Debt [Member] | Debt Maturing October 2019, 4.650% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.65%
Current maturities of long-term debt	$ 100
Progress Energy [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 1,276	1,672
Progress Energy [Member] | Secured Debt [Member] | Debt Maturing December 2019, 4.875% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.875%
Current maturities of long-term debt	$ 350
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 621	270
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | Bonds Maturing January 2020, 1.850% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	1.85%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | Bonds Maturing April 2020, 4.550% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.55%
Current maturities of long-term debt	$ 250
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 457	6
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | Bonds Maturing June 2020, 4.300% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.30%
Current maturities of long-term debt	$ 450
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 651	63
Duke Energy Indiana [Member] | First Mortgage Bonds [Member] | Bonds Maturing July 2020, 3.750% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	3.75%
Current maturities of long-term debt	$ 500
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 306	$ 603
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | Bonds Maturing September 2020, 2.282% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	2.282%
Current maturities of long-term debt	$ 300

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - Revolving Credit Facility [Member]	Sep. 30, 2019USD ($)
Line of Credit Facility [Line Items]
Facility size	$ 8,000,000,000
Commercial paper	(1,971,000,000)
Outstanding letters of credit	(51,000,000)
Tax exempt bonds	(81,000,000)
Coal ash set-aside	(500,000,000)
Available capacity	5,397,000,000
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	2,650,000,000
Commercial paper	(627,000,000)
Outstanding letters of credit	(43,000,000)
Available capacity	1,980,000,000
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility size	1,750,000,000
Commercial paper	(338,000,000)
Outstanding letters of credit	(4,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	1,158,000,000
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,250,000,000
Commercial paper	(211,000,000)
Outstanding letters of credit	(2,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	787,000,000
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	800,000,000
Commercial paper	(277,000,000)
Available capacity	523,000,000
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	450,000,000
Commercial paper	(164,000,000)
Available capacity	286,000,000
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600,000,000
Commercial paper	(150,000,000)
Tax exempt bonds	(81,000,000)
Available capacity	369,000,000
Piedmont Natural Gas [Member]
Line of Credit Facility [Line Items]
Facility size	500,000,000
Commercial paper	(204,000,000)
Outstanding letters of credit	(2,000,000)
Available capacity	294,000,000
Proceeds Loaned To Subsidiary Registrants [Member] | Parent Company [Member]
Line of Credit Facility [Line Items]
Commercial paper	$ (625,000,000)

Debt and Credit Facilities (S_3

Debt and Credit Facilities (Schedule of Other Credit Facilities) (Details)	9 Months Ended
	Sep. 30, 2019USD ($)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	$ 8,000,000,000
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,250,000,000
Duke Energy Progress [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Facility size	700,000,000
Amount drawn	700,000,000
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	$ 500,000,000
Duke Energy (Parent) Three-Year Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Term	3 years
Facility size	$ 1,000,000,000
Amount drawn	$ 500,000,000

Asset Retirement Obligations (A

Asset Retirement Obligations (ARO by Category) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Total ARO	$ 12,601	$ 10,467
Less: current portion	861	919
Total noncurrent ARO	11,740	9,548
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,398	3,949
Less: current portion	214	290
Total noncurrent ARO	5,184	3,659
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,088	5,411
Less: current portion	478	514
Total noncurrent ARO	5,610	4,897
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,514	4,820
Less: current portion	476	509
Total noncurrent ARO	5,038	4,311
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	574	591
Less: current portion	2	5
Total noncurrent ARO	572	586
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	85	93
Less: current portion	3	6
Total noncurrent ARO	82	87
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	824	722
Less: current portion	165	109
Total noncurrent ARO	659	613
Piedmont Natural Gas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	20	19
Total noncurrent ARO	20	$ 19
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,789
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,435
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,295
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,769
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	526
Closure of Ash Impoundments [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,486
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,917
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,722
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,707
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	15
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	43
Closure of Ash Impoundments [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	804
Other [Member]
Asset Retirement Obligations [Line Items]
Total ARO	326
Other [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	46
Other [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	71
Other [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	38
Other [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	33
Other [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	42
Other [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	20
Other [Member] | Piedmont Natural Gas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	$ 20

Asset Retirement Obligations _2

Asset Retirement Obligations (ARO Rollforward) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	$ 10,467
Accretion expense	377
Liabilities settled	(691)
Revision in estimates of cash flows	2,448
Balance at end of period	12,601
Duke Energy Carolinas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	3,949
Accretion expense	173
Liabilities settled	(276)
Revision in estimates of cash flows	1,552
Balance at end of period	5,398
Progress Energy [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	5,411
Accretion expense	190
Liabilities settled	(375)
Revision in estimates of cash flows	862
Balance at end of period	6,088
Duke Energy Progress [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	4,820
Accretion expense	171
Liabilities settled	(341)
Revision in estimates of cash flows	864
Balance at end of period	5,514
Duke Energy Florida [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	591
Accretion expense	19
Liabilities settled	(34)
Revision in estimates of cash flows	(2)
Balance at end of period	574
Duke Energy Ohio [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	93
Accretion expense	3
Liabilities settled	(9)
Revision in estimates of cash flows	(2)
Balance at end of period	85
Duke Energy Indiana [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	722
Accretion expense	21
Liabilities settled	(32)
Revision in estimates of cash flows	113
Balance at end of period	824
Piedmont Natural Gas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	19
Accretion expense	1
Balance at end of period	$ 20

Asset Retirement Obligations (N

Asset Retirement Obligations (NDTF Information) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	$ 6,403	$ 5,579
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	3,614	3,133
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	2,789	2,446
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	$ 2,753	$ 2,446

Goodwill (Rollforward of Goodwi

Goodwill (Rollforward of Goodwill) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill balance	$ 19,425	$ 19,425
Accumulated impairment charges	(122)	(122)
Goodwill balance, adjusted for accumulated impairment charges	19,303	19,303
Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill balance	17,379	17,379
Goodwill balance, adjusted for accumulated impairment charges	17,379	17,379
Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill balance	1,924	1,924
Goodwill balance, adjusted for accumulated impairment charges	1,924	1,924
Commercial Renewables [Member]
Goodwill [Line Items]
Goodwill balance	122	122
Accumulated impairment charges	$ (122)	$ (122)

Goodwill (Narrative) (Details)

Goodwill (Narrative) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill	$ 19,303,000,000	$ 19,303,000,000
Accumulated impairment charges	122,000,000	122,000,000
Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	17,379,000,000	17,379,000,000
Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	1,924,000,000	1,924,000,000
Duke Energy Ohio [Member]
Goodwill [Line Items]
Goodwill	920,000,000	920,000,000
Accumulated impairment charges	216,000,000	216,000,000
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	596,000,000	596,000,000
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	324,000,000	324,000,000
Progress Energy [Member]
Goodwill [Line Items]
Goodwill	3,655,000,000	3,655,000,000
Accumulated impairment charges	0	0
Piedmont Natural Gas [Member]
Goodwill [Line Items]
Goodwill	49,000,000	49,000,000
Accumulated impairment charges	$ 0	$ 0

Related Party Transactions (Oth

Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Duke Energy Carolinas [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 197	$ 214	$ 606	$ 647
Duke Energy Carolinas [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6	15	17
Duke Energy Carolinas [Member] | JDA [Member] | Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	12	13	52	66
Related party transaction, expenses from transactions with related party	32	61	145	134
Duke Energy Carolinas [Member] | Intercompany natural gas transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party		3	7	11
Progress Energy [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	194	216	553	613
Progress Energy [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	8	8	27	25
Progress Energy [Member] | JDA [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	32	61	145	134
Related party transaction, expenses from transactions with related party	12	13	52	66
Progress Energy [Member] | Intercompany natural gas transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19	20	57	58
Duke Energy Progress [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	114	138	328	382
Duke Energy Progress [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	3	3	11	9
Duke Energy Progress [Member] | JDA [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	32	61	145	134
Related party transaction, expenses from transactions with related party	12	13	52	66
Duke Energy Progress [Member] | Intercompany natural gas transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19	20	57	58
Duke Energy Florida [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	80	78	225	231
Duke Energy Florida [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	5	16	16
Duke Energy Ohio [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	90	85	258	264
Duke Energy Ohio [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1	1	3	3
Duke Energy Indiana [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	109	105	299	302
Duke Energy Indiana [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	2	2	5	6
Piedmont Natural Gas [Member] | Corporate governance and shared service expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	33	39	102	115
Piedmont Natural Gas [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1	1	2	2
Piedmont Natural Gas [Member] | Intercompany natural gas transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	19	23	64	69
Piedmont Natural Gas [Member] | Natural gas storage and transportation costs [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 6	$ 6	$ 17	$ 18

Related Party Transactions (Int

Related Party Transactions (Intercompany Income Taxes) (Details) - Affiliated Entity [Member] - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Income taxes receivable		$ 52
Income tax payable	$ 71
Progress Energy [Member]
Related Party Transaction [Line Items]
Income taxes receivable	178	47
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Income taxes receivable	60	29
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Income taxes receivable	10
Income tax payable		16
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Income taxes receivable	14
Income tax payable		3
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Income taxes receivable	3	8
Piedmont Natural Gas [Member]
Related Party Transaction [Line Items]
Income taxes receivable	$ 85
Income tax payable		$ 45

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)GWhMcf	Dec. 31, 2018USD ($)GWhMcf
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	25,658	15,286
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	729	739
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 2,608	$ 2,644
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	1,031	923
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	1,577	1,721
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	731	422
Variable Interest Entity, Primary Beneficiary [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 194	$ 194
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	130	121
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 450	$ 300
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 450	$ 300
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	175	169
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 1,100	$ 1,200
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 1,100	$ 1,200
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	175	166
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	$ 650
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	$ 650
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf		3
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	850	$ 550
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 850	$ 550
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	2,774	1,786
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 27	$ 27
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 27	$ 27
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	22,884	13,500
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	4	1
Piedmont Natural Gas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	420	448

Derivatives and Hedging (Locati

Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 31	$ 57
Location and fair value amounts of derivatives (Liability)	353	242
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	31	38
Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		19
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	142	68
Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	211	174
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	23	39
Location and fair value amounts of derivatives (Liability)	213	191
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	18
Location and fair value amounts of derivatives (Liability)	130	51
Equity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Location and fair value amounts of derivatives (Liability)	10
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	1
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2	12
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	56	6
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	23	35
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	66	33
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	147	158
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		12
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	64	23
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	10
Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	67	33
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	55	23
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	12	10
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	45	24
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	9
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	33	14
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	12	10
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	9
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	4
Location and fair value amounts of derivatives (Liability)	113	44
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Progress Energy [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	76	23
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	21
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	58	25
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	45	19
Progress Energy [Member] | Equity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Location and fair value amounts of derivatives (Liability)	10
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24	10
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	34	15
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	42	13
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	6
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	43	27
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	25	16
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	11
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	42	11
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	16
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24	5
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	6
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	11
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Location and fair value amounts of derivatives (Liability)	54	9
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	51	8
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	1
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	44	3
Duke Energy Florida [Member] | Equity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Location and fair value amounts of derivatives (Liability)	10
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	41	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	1
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	6
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	6
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	4
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	6
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	6
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	4
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	23
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	23
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	23
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	23
Piedmont Natural Gas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Location and fair value amounts of derivatives (Liability)	111	141
Piedmont Natural Gas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Piedmont Natural Gas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	9	8
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	102	133
Piedmont Natural Gas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Location and fair value amounts of derivatives (Liability)	111	141
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	9	8
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 102	$ 133

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 31	$ 57
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	57
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	31	38
Gross amounts offset	(5)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	26	35
Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		19
Gross amounts offset		(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet		16
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		3
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		1
Gross amounts offset		(1)
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	4
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Gross amounts offset	(5)	(2)
Progress Energy [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		4
Net amounts recognized on the Condensed Consolidated Balance Sheet		4
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(5)
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	6
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	23
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	23
Piedmont Natural Gas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	3
Piedmont Natural Gas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 2	$ 3

Derivatives and Hedging (Sche_2

Derivatives and Hedging (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 353	$ 242
Net amounts recognized on the Condensed Consolidated Balance Sheet	353	242
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	142	68
Gross amounts offset	(10)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	132	64
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	211	174
Gross amounts offset		(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	211	171
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	67	33
Net amounts recognized on the Condensed Consolidated Balance Sheet	67	33
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	55	23
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	21
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	10
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	9
Progress Energy [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	113	44
Net amounts recognized on the Condensed Consolidated Balance Sheet	113	44
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	76	23
Gross amounts offset	(10)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	66	21
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	37	21
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	37	19
Duke Energy Progress [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	43	27
Net amounts recognized on the Condensed Consolidated Balance Sheet	43	27
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	25	16
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	14
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	11
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	9
Duke Energy Florida [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	54	9
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	9
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	51	8
Gross amounts offset	(10)
Net amounts recognized on the Condensed Consolidated Balance Sheet	41	8
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	3	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	1
Duke Energy Ohio [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	5
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	4
Piedmont Natural Gas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	111	141
Net amounts recognized on the Condensed Consolidated Balance Sheet	111	141
Piedmont Natural Gas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	9	8
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	8
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	102	133
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 102	$ 133

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	$ 82	$ 44
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	82	44
Duke Energy Carolinas [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	40	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	40	19
Progress Energy [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	42	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	42	25
Duke Energy Progress [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	42	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 42	$ 25

Derivatives and Hedging (Narrat

Derivatives and Hedging (Narrative) (Details)	Sep. 30, 2019shares
Call Option [Member]
Derivative [Line Items]
Aggregate notional amount	305,000
Put Option [Member]
Derivative [Line Items]
Aggregate notional amount	305,000

Investments in Debt and Equit_3

Investments in Debt and Equity Securities (All Debt and Equity Securities Through OCI and FV-NI - ASU 2016-01) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	$ 3,274	$ 2,458
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	64	131
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	8,134	7,075
Debt securities, available-for-sale	2,633
Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	3,118	2,402
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	3,215	2,421
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	64	126
Cash and cash equivalents	114	88
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	7,698	6,706
Equity Securities, FV-NI, Accumulated Unrealized Loss	63	95
Equity securities, FV-NI	5,222	4,475
Debt securities, available-for-sale	2,476	2,231
Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	48	36
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	59	37
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss		5
Cash and cash equivalents	53	22
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	436	369
Equity Securities, FV-NI, Accumulated Unrealized Loss		1
Equity securities, FV-NI	112	99
Debt securities, available-for-sale	324	270
Duke Energy Carolinas [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt securities, available-for-sale	1,159
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,680	1,309
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,731	1,316
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	16	74
Cash and cash equivalents	36	29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	4,096	3,553
Equity Securities, FV-NI, Accumulated Unrealized Loss	15	54
Equity securities, FV-NI	2,901	2,484
Debt securities, available-for-sale	1,195	1,069
Progress Energy [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,488	1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	48	52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,703	3,217
Debt securities, available-for-sale	1,255
Progress Energy [Member] | Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,438	1,093
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,484	1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	48	52
Cash and cash equivalents	78	59
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,602	3,153
Equity Securities, FV-NI, Accumulated Unrealized Loss	48	41
Equity securities, FV-NI	2,321	1,991
Debt securities, available-for-sale	1,281	1,162
Progress Energy [Member] | Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	4
Cash and cash equivalents	49	17
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	101	64
Debt securities, available-for-sale	101	64
Duke Energy Progress [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,152	842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	30	39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,884	2,500
Debt securities, available-for-sale	923
Duke Energy Progress [Member] | Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,107	833
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,152	842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	30	39
Cash and cash equivalents	52	46
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,882	2,494
Equity Securities, FV-NI, Accumulated Unrealized Loss	30	30
Equity securities, FV-NI	1,907	1,588
Debt securities, available-for-sale	975	906
Duke Energy Progress [Member] | Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Cash and cash equivalents	2	6
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2	6
Debt securities, available-for-sale	2	6
Duke Energy Florida [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	336	263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	18	13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	776	707
Debt securities, available-for-sale	332
Duke Energy Florida [Member] | Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	331	260
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	332	263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	18	13
Cash and cash equivalents	26	13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	720	659
Equity Securities, FV-NI, Accumulated Unrealized Loss	18	11
Equity securities, FV-NI	414	403
Debt securities, available-for-sale	306	256
Duke Energy Florida [Member] | Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	4
Cash and cash equivalents	4	1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	56	48
Debt securities, available-for-sale	56	48
Duke Energy Indiana [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	37	29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	38	29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss		1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	117	108
Equity securities, FV-NI	74	67
Debt securities, available-for-sale	43
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity securities, FV-NI	$ 74	$ 67

Investments in Debt and Equit_4

Investments in Debt and Equity Securities (Equity Securities, FV-NI - ASU 2016-01) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	$ 60	$ 19	$ 161	$ 85
Equity securities, FV-NI, realized loss	43	16	136	60
Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	3,118		3,118		$ 2,402
Equity Securities, FV-NI, Accumulated Unrealized Loss	63		63		95
Equity securities, FV-NI	5,222		5,222		4,475
Other Classification [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	48		48		36
Equity Securities, FV-NI, Accumulated Unrealized Loss					1
Equity securities, FV-NI	112		112		99
Duke Energy Carolinas [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	34	11	101	47
Equity securities, FV-NI, realized loss	26	8	95	30
Duke Energy Carolinas [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,680		1,680		1,309
Equity Securities, FV-NI, Accumulated Unrealized Loss	15		15		54
Equity securities, FV-NI	2,901		2,901		2,484
Progress Energy [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	26	8	60	38
Equity securities, FV-NI, realized loss	17	8	41	30
Progress Energy [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,438		1,438		1,093
Equity Securities, FV-NI, Accumulated Unrealized Loss	48		48		41
Equity securities, FV-NI	2,321		2,321		1,991
Duke Energy Progress [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	10	7	27	32
Equity securities, FV-NI, realized loss	9	7	24	27
Duke Energy Progress [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,107		1,107		833
Equity Securities, FV-NI, Accumulated Unrealized Loss	30		30		30
Equity securities, FV-NI	1,907		1,907		1,588
Duke Energy Florida [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	16	1	33	6
Equity securities, FV-NI, realized loss	8	$ 1	17	$ 3
Duke Energy Florida [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	331		331		260
Equity Securities, FV-NI, Accumulated Unrealized Loss	18		18		11
Equity securities, FV-NI	414		414		403
Duke Energy Indiana [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	37		37		29
Equity securities, FV-NI	74		74		67
Duke Energy Indiana [Member] | Other Classification [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity securities, FV-NI	$ 74		$ 74		$ 67

Investments in Debt Securities

Investments in Debt Securities and Equity Securities (Available-for-sale, OCI - ASU 2016-01) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	$ 2,633		$ 2,633
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	53	$ 4	110	$ 14
Debt securities, available-for-sale, realized loss	36	7	83	32
Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	2,476		2,476		$ 2,231
Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	324		324		270
Corporate debt securities [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	40		40		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		1		13
Debt securities, available-for-sale	633		633		566
Corporate debt securities [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	2		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					2
Debt securities, available-for-sale	72		72		60
Municipal bonds [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	14		14		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					4
Debt securities, available-for-sale	370		370		353
Municipal bonds [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	5		5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	94		94		85
US treasury and government [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	39		39		14
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					12
Debt securities, available-for-sale	1,217		1,217		1,076
US treasury and government [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	3		3		1
Debt securities, available-for-sale	40		40		45
Other debt obligations [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					2
Debt securities, available-for-sale	142		142		148
Other debt obligations [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	65		65		58
Duke Energy Carolinas [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,159		1,159
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	21	4	46	13
Debt securities, available-for-sale, realized loss	13	6	34	24
Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,195		1,195		1,069
Duke Energy Carolinas [Member] | Corporate debt securities [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	24		24		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		1		9
Debt securities, available-for-sale	409		409		341
Duke Energy Carolinas [Member] | Municipal bonds [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	96		96		81
Duke Energy Carolinas [Member] | US treasury and government [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	19		19		5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					8
Debt securities, available-for-sale	517		517		475
Duke Energy Carolinas [Member] | Other debt obligations [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					2
Debt securities, available-for-sale	137		137		143
Progress Energy [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,255		1,255
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	31		62	1
Debt securities, available-for-sale, realized loss	23	1	49	8
Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,281		1,281		1,162
Progress Energy [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	101		101		64
Progress Energy [Member] | Corporate debt securities [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	16		16		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					4
Debt securities, available-for-sale	224		224		225
Progress Energy [Member] | Municipal bonds [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	10		10		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	274		274		272
Progress Energy [Member] | Municipal bonds [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale	52		52		47
Progress Energy [Member] | US treasury and government [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	20		20		9
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					4
Debt securities, available-for-sale	700		700		601
Progress Energy [Member] | Other debt obligations [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	5		5		5
Duke Energy Progress [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	923		923
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	2		4	1
Debt securities, available-for-sale, realized loss		$ 1	2	6
Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	975		975		906
Duke Energy Progress [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	2		2		6
Duke Energy Progress [Member] | Corporate debt securities [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	16		16		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	224		224		171
Duke Energy Progress [Member] | Municipal bonds [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	10		10		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	274		274		271
Duke Energy Progress [Member] | US treasury and government [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	19		19		6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	420		420		415
Duke Energy Progress [Member] | Other debt obligations [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	5		5		3
Duke Energy Florida [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	332		332
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	29		58
Debt securities, available-for-sale, realized loss	23		47	$ 2
Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	306		306		256
Duke Energy Florida [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	56		56		48
Duke Energy Florida [Member] | Corporate debt securities [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale					54
Duke Energy Florida [Member] | Municipal bonds [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale					1
Duke Energy Florida [Member] | Municipal bonds [Member] | Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale	52		52		47
Duke Energy Florida [Member] | US treasury and government [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1		1		3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	280		280		186
Duke Energy Florida [Member] | Other debt obligations [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale					2
Duke Energy Indiana [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	43		43
Duke Energy Indiana [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	6		6		8
Duke Energy Indiana [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	36		36		$ 33
Duke Energy Indiana [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	$ 1		$ 1

Investments in Debt and Equit_5

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, realized loss	$ 36	$ 7	$ 83	$ 32
Debt securities, available-for-sale, realized gain	53	4	110	14
Equity securities, FV-NI, realized loss	43	16	136	60
Equity securities, FV-NI, realized gain	60	19	161	85
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	3,274		3,274		$ 2,458
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	64		64		131
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	8,134		8,134		7,075
Debt securities, available-for-sale	2,633		2,633
Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	3,215		3,215		2,421
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	64		64		126
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	7,698		7,698		6,706
Debt securities, available-for-sale	2,476		2,476		2,231
Equity Securities, FV-NI, Accumulated Unrealized Gain	3,118		3,118		2,402
Equity Securities, FV-NI, Accumulated Unrealized Loss	63		63		95
Cash and cash equivalents	114		114		88
Equity securities, FV-NI	5,222		5,222		4,475
Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	59		59		37
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss					5
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	436		436		369
Debt securities, available-for-sale	324		324		270
Equity Securities, FV-NI, Accumulated Unrealized Gain	48		48		36
Equity Securities, FV-NI, Accumulated Unrealized Loss					1
Cash and cash equivalents	53		53		22
Equity securities, FV-NI	112		112		99
Duke Energy Carolinas [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, realized loss	13	6	34	24
Debt securities, available-for-sale, realized gain	21	4	46	13
Equity securities, FV-NI, realized loss	26	8	95	30
Equity securities, FV-NI, realized gain	34	11	101	47
Debt securities, available-for-sale	1,159		1,159
Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,731		1,731		1,316
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	16		16		74
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	4,096		4,096		3,553
Debt securities, available-for-sale	1,195		1,195		1,069
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,680		1,680		1,309
Equity Securities, FV-NI, Accumulated Unrealized Loss	15		15		54
Cash and cash equivalents	36		36		29
Equity securities, FV-NI	2,901		2,901		2,484
Progress Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, realized loss	23	1	49	8
Debt securities, available-for-sale, realized gain	31		62	1
Equity securities, FV-NI, realized loss	17	8	41	30
Equity securities, FV-NI, realized gain	26	8	60	38
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,488		1,488		1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	48		48		52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,703		3,703		3,217
Debt securities, available-for-sale	1,255		1,255
Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,484		1,484		1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	48		48		52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,602		3,602		3,153
Debt securities, available-for-sale	1,281		1,281		1,162
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,438		1,438		1,093
Equity Securities, FV-NI, Accumulated Unrealized Loss	48		48		41
Cash and cash equivalents	78		78		59
Equity securities, FV-NI	2,321		2,321		1,991
Progress Energy [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	4		4
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	101		101		64
Debt securities, available-for-sale	101		101		64
Cash and cash equivalents	49		49		17
Duke Energy Progress [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, realized loss		1	2	6
Debt securities, available-for-sale, realized gain	2		4	1
Equity securities, FV-NI, realized loss	9	7	24	27
Equity securities, FV-NI, realized gain	10	7	27	32
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,152		1,152		842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	30		30		39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,884		2,884		2,500
Debt securities, available-for-sale	923		923
Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,152		1,152		842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	30		30		39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,882		2,882		2,494
Debt securities, available-for-sale	975		975		906
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,107		1,107		833
Equity Securities, FV-NI, Accumulated Unrealized Loss	30		30		30
Cash and cash equivalents	52		52		46
Equity securities, FV-NI	1,907		1,907		1,588
Duke Energy Progress [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2		2		6
Debt securities, available-for-sale	2		2		6
Cash and cash equivalents	2		2		6
Duke Energy Florida [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, realized loss	23		47	2
Debt securities, available-for-sale, realized gain	29		58
Equity securities, FV-NI, realized loss	8	1	17	3
Equity securities, FV-NI, realized gain	16	$ 1	33	$ 6
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	336		336		263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	18		18		13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	776		776		707
Debt securities, available-for-sale	332		332
Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	332		332		263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	18		18		13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	720		720		659
Debt securities, available-for-sale	306		306		256
Equity Securities, FV-NI, Accumulated Unrealized Gain	331		331		260
Equity Securities, FV-NI, Accumulated Unrealized Loss	18		18		11
Cash and cash equivalents	26		26		13
Equity securities, FV-NI	414		414		403
Duke Energy Florida [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	4		4
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	56		56		48
Debt securities, available-for-sale	56		56		48
Cash and cash equivalents	4		4		1
Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	38		38		29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss					1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	117		117		108
Debt securities, available-for-sale	43		43
Equity Securities, FV-NI, Accumulated Unrealized Gain	37		37		29
Equity securities, FV-NI	74		74		67
Duke Energy Indiana [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Equity securities, FV-NI	74		74		67
Corporate debt securities [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	40		40		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		1		13
Debt securities, available-for-sale	633		633		566
Corporate debt securities [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	2		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					2
Debt securities, available-for-sale	72		72		60
Corporate debt securities [Member] | Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	24		24		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		1		9
Debt securities, available-for-sale	409		409		341
Corporate debt securities [Member] | Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	16		16		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					4
Debt securities, available-for-sale	224		224		225
Corporate debt securities [Member] | Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	16		16		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	224		224		171
Corporate debt securities [Member] | Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale					54
Corporate debt securities [Member] | Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	6		6		8
Municipal bonds [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	14		14		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					4
Debt securities, available-for-sale	370		370		353
Municipal bonds [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	5		5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	94		94		85
Municipal bonds [Member] | Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	96		96		81
Municipal bonds [Member] | Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	10		10		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	274		274		272
Municipal bonds [Member] | Progress Energy [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale	52		52		47
Municipal bonds [Member] | Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	10		10		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	274		274		271
Municipal bonds [Member] | Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale					1
Municipal bonds [Member] | Duke Energy Florida [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale	52		52		47
Municipal bonds [Member] | Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	36		36		33
US treasury and government [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	39		39		14
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					12
Debt securities, available-for-sale	1,217		1,217		1,076
US treasury and government [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	3		3		1
Debt securities, available-for-sale	40		40		45
US treasury and government [Member] | Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	19		19		5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					8
Debt securities, available-for-sale	517		517		475
US treasury and government [Member] | Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	20		20		9
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					4
Debt securities, available-for-sale	700		700		601
US treasury and government [Member] | Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	19		19		6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					3
Debt securities, available-for-sale	420		420		415
US treasury and government [Member] | Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1		1		3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	280		280		186
US treasury and government [Member] | Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	1		1
Other debt obligations [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					2
Debt securities, available-for-sale	142		142		148
Other debt obligations [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					1
Debt securities, available-for-sale	65		65		58
Other debt obligations [Member] | Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax					2
Debt securities, available-for-sale	137		137		143
Other debt obligations [Member] | Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	5		5		5
Other debt obligations [Member] | Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	$ 5		$ 5		3
Other debt obligations [Member] | Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale					$ 2

Investments in Debt and Equit_6

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Sep. 30, 2019USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 400
Due after one through five years	524
Due after five through 10 years	450
Due after 10 years	1,259
Total	2,633
Duke Energy Carolinas [Member]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	65
Due after one through five years	220
Due after five through 10 years	187
Due after 10 years	687
Total	1,159
Progress Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	328
Due after one through five years	253
Due after five through 10 years	209
Due after 10 years	465
Total	1,255
Duke Energy Progress [Member]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	48
Due after one through five years	243
Due after five through 10 years	201
Due after 10 years	431
Total	923
Duke Energy Florida [Member]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	280
Due after one through five years	10
Due after five through 10 years	8
Due after 10 years	34
Total	332
Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	4
Due after one through five years	15
Due after five through 10 years	5
Due after 10 years	19
Total	$ 43

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 2,633
Derivative assets	31	$ 57
Total assets	8,165	7,132
Derivative liabilities	(353)	(242)
Net assets (liabilities)	7,812	6,890
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	4
Total assets	6,178	5,156
Derivative liabilities	(25)	(11)
Net assets (liabilities)	6,153	5,145
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	25
Total assets	1,912	1,883
Derivative liabilities	(217)	(90)
Net assets (liabilities)	1,695	1,793
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	21	28
Total assets	21	28
Derivative liabilities	(111)	(141)
Net assets (liabilities)	(90)	(113)
Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	54	65
Net assets (liabilities)	54	65
Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	5,222	4,475
Debt securities, available-for-sale	2,476	2,231
Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	5,168	4,410
Debt securities, available-for-sale	804	576
Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,672	1,655
Ndtf [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	54	65
Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	112	99
Debt securities, available-for-sale	324	270
Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	112	99
Debt securities, available-for-sale	92	67
Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	232	203
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,159
Derivative assets		3
Total assets	4,096	3,556
Derivative liabilities	(67)	(33)
Net assets (liabilities)	4,029	3,523
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3,036	2,568
Net assets (liabilities)	3,036	2,568
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		3
Total assets	1,006	923
Derivative liabilities	(67)	(33)
Net assets (liabilities)	939	890
Duke Energy Carolinas [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	54	65
Net assets (liabilities)	54	65
Duke Energy Carolinas [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,901	2,484
Debt securities, available-for-sale	1,195	1,069
Duke Energy Carolinas [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,847	2,419
Debt securities, available-for-sale	189	149
Duke Energy Carolinas [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,006	920
Duke Energy Carolinas [Member] | Ndtf [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	54	65
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,255
Derivative assets	5	4
Total assets	3,708	3,221
Derivative liabilities	(113)	(44)
Net assets (liabilities)	3,595	3,177
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,985	2,435
Derivative liabilities	0
Net assets (liabilities)	2,985	2,435
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	4
Total assets	723	786
Derivative liabilities	(113)	(44)
Net assets (liabilities)	610	742
Progress Energy [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,321	1,991
Debt securities, available-for-sale	1,281	1,162
Progress Energy [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,321	1,991
Debt securities, available-for-sale	615	427
Progress Energy [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	666	735
Progress Energy [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	101	64
Progress Energy [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	49	17
Progress Energy [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	52	47
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	923
Derivative assets		4
Total assets	2,884	2,504
Derivative liabilities	(43)	(27)
Net assets (liabilities)	2,841	2,477
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,218	1,888
Derivative liabilities	0
Net assets (liabilities)	2,218	1,888
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		4
Total assets	666	616
Derivative liabilities	(43)	(27)
Net assets (liabilities)	623	589
Duke Energy Progress [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	1,907	1,588
Debt securities, available-for-sale	975	906
Duke Energy Progress [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	1,907	1,588
Debt securities, available-for-sale	309	294
Duke Energy Progress [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	666	612
Duke Energy Progress [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	2	6
Duke Energy Progress [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	2	6
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	332
Derivative assets	5
Total assets	781	707
Derivative liabilities	(54)	(9)
Net assets (liabilities)	727	698
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	724	537
Net assets (liabilities)	724	537
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5
Total assets	57	170
Derivative liabilities	(54)	(9)
Net assets (liabilities)	3	161
Duke Energy Florida [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	414	403
Debt securities, available-for-sale	306	256
Duke Energy Florida [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	414	403
Debt securities, available-for-sale	306	133
Duke Energy Florida [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale		123
Duke Energy Florida [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	56	48
Duke Energy Florida [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	4	1
Duke Energy Florida [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	52	47
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	74	67
Debt securities, available-for-sale	43
Derivative assets	16	23
Total assets	133	131
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		1
Total assets	74	68
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	43	41
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	16	22
Total assets	16	22
Duke Energy Indiana [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	74	67
Duke Energy Indiana [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	74	67
Piedmont Natural Gas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	3
Derivative liabilities	(111)	(141)
Net assets (liabilities)	(109)	(138)
Piedmont Natural Gas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	3
Net assets (liabilities)	2	3
Piedmont Natural Gas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(111)	(141)
Net assets (liabilities)	(111)	(141)
Debt Securities [Member] | Duke Energy Indiana [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	43	41
Debt Securities [Member] | Duke Energy Indiana [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 43	$ 41

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 ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement, transfers between activity levels	$ 0	$ 0	$ 0	$ 0
Derivatives (net)
Balance at beginning of period	(79,000,000)	(97,000,000)	(113,000,000)	(114,000,000)
Purchases, sales, issuances and settlements:
Purchases			38,000,000	56,000,000
Settlements	(9,000,000)	(14,000,000)	(32,000,000)	(43,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	(2,000,000)	(5,000,000)	17,000,000	(15,000,000)
Balance at end of period	(90,000,000)	(116,000,000)	(90,000,000)	(116,000,000)
Duke Energy Indiana [Member]
Derivatives (net)
Balance at beginning of period	28,000,000	44,000,000	22,000,000	27,000,000
Purchases, sales, issuances and settlements:
Purchases			29,000,000	49,000,000
Settlements	(7,000,000)	(13,000,000)	(26,000,000)	(41,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	(5,000,000)	(2,000,000)	(9,000,000)	(6,000,000)
Balance at end of period	16,000,000	29,000,000	16,000,000	29,000,000
Piedmont Natural Gas [Member]
Derivatives (net)
Balance at beginning of period	(114,000,000)	(150,000,000)	(141,000,000)	(142,000,000)
Purchases, sales, issuances and settlements:
Total gains (losses) and settlements	3,000,000	(3,000,000)	30,000,000	(11,000,000)
Balance at end of period	$ (111,000,000)	$ (153,000,000)	$ (111,000,000)	$ (153,000,000)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosures) (Details) $ in Millions	Sep. 30, 2019USD ($)$ / MWh$ / MMBTU	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)$ / MWh$ / MMBTU	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ (90)	$ (79)	$ (113)	$ (116)	$ (97)	$ (114)
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ 5		$ 6
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Input measurements (in usd per MWh and usd per MMBtu) | $ / MWh	0.57		1.19
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Input measurements (in usd per MWh and usd per MMBtu) | $ / MWh	3.38		4.59
Duke Energy Indiana [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ 16	28	$ 22	29	44	27
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ 16		$ 22
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Input measurements (in usd per MWh and usd per MMBtu) | $ / MWh	(0.52)		(2.07)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Input measurements (in usd per MWh and usd per MMBtu) | $ / MWh	6.85		8.27
Piedmont Natural Gas [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ (111)	$ (114)	$ (141)	$ (153)	$ (150)	$ (142)
Piedmont Natural Gas [Member] | Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ (111)		$ (141)
Piedmont Natural Gas [Member] | Derivative Financial Instruments, Liabilities [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Fair Value Measurement Inputs and Valuation Techniques
Input measurements (in usd per MWh and usd per MMBtu) | $ / MMBTU	1.85		1.87
Piedmont Natural Gas [Member] | Derivative Financial Instruments, Liabilities [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Fair Value Measurement Inputs and Valuation Techniques
Input measurements (in usd per MWh and usd per MMBtu) | $ / MMBTU	2.99		2.95

Fair Value Measurements (Other

Fair Value Measurements (Other Fair Value Disclosure) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	$ 57,914	$ 54,529
Long-term debt, fair value	63,276	54,534
Piedmont Natural Gas and Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized debt discount (premium), net	1,500	1,600
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	11,758	10,939
Long-term debt, fair value	13,462	11,471
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	19,119	18,911
Long-term debt, fair value	21,952	19,885
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	9,049	8,204
Long-term debt, fair value	9,995	8,300
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	7,132	7,321
Long-term debt, fair value	8,356	7,742
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	2,719	2,165
Long-term debt, fair value	3,096	2,239
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	4,208	3,782
Long-term debt, fair value	5,018	4,158
Piedmont Natural Gas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	2,384	2,138
Long-term debt, fair value	$ 2,664	$ 2,180

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,864,000,000	$ 1,409,000,000
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable interest entity, financial or other support, amount	0	0
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,442,000,000	1,060,000,000
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [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
Pioneer Transmission [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable interest entity ownership interest	50.00%
Investments in equity method unconsolidated affiliates	$ 55,000,000
OVEC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable interest entity ownership interest	9.00%
Atlantic Coast Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,127,000,000	$ 797,000,000
Atlantic Coast Pipeline [Member] | Financial Guarantee [Member]
Variable Interest Entities [Line Items]
Maximum potential amount of future payments associated with guarantees	$ 802,000,000
Percentage of potential amount of future payments associated with guarantees as percent of outstanding borrowings	47.00%

Variable Interest Entities (Sch

Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Long-Term Debt	$ 54,818	$ 51,123
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	11,001	10,633
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	8,593	7,451
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	$ 6,511	7,051
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Dec. 1, 2020
Facility size	$ 350
Long-Term Debt	350	325
Accounts receivable from securitization	$ 505	564
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Dec. 1, 2020
Facility size	$ 475
Long-Term Debt	475	450
Accounts receivable from securitization	$ 775	699
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Feb. 1, 2021
Facility size	$ 325
Long-Term Debt	325	300
Accounts receivable from securitization	$ 564	547
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Apr. 1, 2021
Facility size	$ 250
Long-Term Debt	250	225
Accounts receivable from securitization	$ 471	$ 357

Variable Interest Entities (S_2

Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	$ 1,723	$ 2,005
Other, current assets	1,333	1,049
Regulatory assets, noncurrent	13,916	13,617
Property, plant and equipment, cost	143,794	134,458
Accumulated depreciation and amortization	(45,149)	(43,126)
Other noncurrent assets	2,905	2,935
Current Liabilities: Other	2,074	2,085
Current maturities of long-term debt	3,096	3,406
Long-Term Debt	54,818	51,123
Other Noncurrent Liabilities: Asset retirement obligations	11,740	9,548
Other Noncurrent Liabilities: Other	1,649	1,650
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	573	520
Other, current assets	19	72
Regulatory assets, noncurrent	3,587	3,457
Property, plant and equipment, cost	47,815	44,741
Accumulated depreciation and amortization	(16,359)	(15,496)
Other noncurrent assets	1,061	1,027
Current Liabilities: Other	545	571
Current maturities of long-term debt	457	6
Long-Term Debt	11,001	10,633
Other Noncurrent Liabilities: Asset retirement obligations	5,184	3,659
Other Noncurrent Liabilities: Other	617	671
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	515	703
Other, current assets	95	62
Regulatory assets, noncurrent	4,363	4,111
Property, plant and equipment, cost	33,594	31,459
Accumulated depreciation and amortization	(11,761)	(11,423)
Other noncurrent assets	595	612
Current Liabilities: Other	416	408
Current maturities of long-term debt	306	603
Long-Term Debt	8,593	7,451
Other Noncurrent Liabilities: Asset retirement obligations	5,038	4,311
Other Noncurrent Liabilities: Other	105	106
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	367	434
Other, current assets	42	46
Regulatory assets, noncurrent	2,370	2,454
Property, plant and equipment, cost	19,887	18,792
Accumulated depreciation and amortization	(5,148)	(4,968)
Other noncurrent assets	307	311
Current Liabilities: Other	423	406
Current maturities of long-term debt	621	270
Long-Term Debt	6,511	7,051
Other Noncurrent Liabilities: Asset retirement obligations	572	586
Other Noncurrent Liabilities: Other	102	93
DEFPF [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	7	5
Regulatory assets, current	52	52
Other, current assets	16	39
Regulatory assets, noncurrent	1,002	1,041
Current Liabilities: Other	2	10
Current maturities of long-term debt	54	53
Long-Term Debt	1,056	1,111
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	775	699
Long-Term Debt	475	450
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	564	547
Long-Term Debt	325	300
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	471	357
Long-Term Debt	250	225
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	505	564
Long-Term Debt	350	325
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Other, current assets	172	123
Property, plant and equipment, cost	5,160	4,007
Accumulated depreciation and amortization	(996)	(698)
Other noncurrent assets	63	261
Current maturities of long-term debt	177	174
Long-Term Debt	1,604	1,587
Other Noncurrent Liabilities: Asset retirement obligations	125	106
Other Noncurrent Liabilities: Other	$ 218	$ 212

Variable Interest Entities (S_3

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,864	$ 1,409
Taxes accrued	712	577
Current Liabilities: Other	2,074	2,085
Deferred income taxes	8,776	7,806
Other Noncurrent Liabilities: Other	1,649	1,650
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	1,442	1,060
Total assets	1,442	1,060
Taxes accrued	(2)	(1)
Current Liabilities: Other	3	4
Deferred income taxes	57	21
Other Noncurrent Liabilities: Other	11	12
Total liabilities	69	36
Net assets	1,373	1,024
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	1,152	822
Total assets	1,152	822
Taxes accrued	(2)	(1)
Deferred income taxes	57	21
Total liabilities	55	20
Net assets	1,097	802
Commercial Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	235	190
Total assets	235	190
Net assets	235	190
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	55	48
Total assets	55	48
Current Liabilities: Other	3	4
Other Noncurrent Liabilities: Other	11	12
Total liabilities	14	16
Net assets	41	32
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	63	114
Taxes accrued	162	202
Current Liabilities: Other	74	74
Deferred income taxes	901	817
Other Noncurrent Liabilities: Other	95	93
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	48	93
Total assets	48	93
Net assets	48	93
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	85	122
Taxes accrued	29	43
Current Liabilities: Other	107	107
Deferred income taxes	1,119	1,009
Other Noncurrent Liabilities: Other	57	16
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	76	118
Total assets	76	118
Net assets	$ 76	$ 118

Variable Interest Entities (Pip

Variable Interest Entities (Pipeline Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 1,864	$ 1,409
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 1,442	1,060
Atlantic Coast Pipeline [Member]
Variable Interest Entities [Line Items]
Ownership percentage	47.00%
Atlantic Coast Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 1,127	797
Constitution Pipeline [Member]
Variable Interest Entities [Line Items]
Ownership percentage	24.00%
Constitution Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 25	25
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 1,152	$ 822

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold) (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 217	$ 269
Less: Retained interests	48	93
Net receivables sold	169	176
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	326	336
Less: Retained interests	76	118
Net receivables sold	$ 250	$ 218

Variable Interest Entities (Sal

Variable Interest Entities (Sales and Cash Flows) (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 479	$ 450	$ 1,483	$ 1,478
Loss recognized on sale	4	4	11	10
Cash proceeds from receivables sold	471	449	1,516	1,499
Collection fees received			1	1
Return received on retained interests	1	2	5	5
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	762	754	2,172	2,140
Loss recognized on sale	4	5	13	12
Cash proceeds from receivables sold	762	743	2,200	2,140
Collection fees received			1	1
Return received on retained interests	$ 2	$ 3	$ 7	$ 7

Revenue (Remaining Performance

Revenue (Remaining Performance Obligations) (Details) $ in Millions	Sep. 30, 2019USD ($)
Progress Energy [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, remaining performance obligation, amount	$ 31
Progress Energy [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 121
Progress Energy [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 86
Progress Energy [Member] | 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
Revenue, remaining performance obligation, amount	$ 81
Progress Energy [Member] | 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
Revenue, remaining performance obligation, amount	$ 38
Progress Energy [Member] | 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
Revenue, remaining performance obligation, amount	$ 41
Progress Energy [Member] | 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	$ 398
Duke Energy Progress [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, remaining performance obligation, amount	$ 2
Duke Energy Progress [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 8
Duke Energy Progress [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 8
Duke Energy Progress [Member] | 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
Revenue, remaining performance obligation, amount	$ 8
Duke Energy Progress [Member] | 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
Revenue, remaining performance obligation, amount	$ 8
Duke Energy Progress [Member] | 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
Revenue, remaining performance obligation, amount	$ 8
Duke Energy Progress [Member] | 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	$ 42
Duke Energy Florida [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, remaining performance obligation, amount	$ 29
Duke Energy Florida [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 113
Duke Energy Florida [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 78
Duke Energy Florida [Member] | 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
Revenue, remaining performance obligation, amount	$ 73
Duke Energy Florida [Member] | 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
Revenue, remaining performance obligation, amount	$ 30
Duke Energy Florida [Member] | 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
Revenue, remaining performance obligation, amount	$ 33
Duke Energy Florida [Member] | 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	$ 356
Duke Energy Indiana [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, remaining performance obligation, amount	$ 2
Duke Energy Indiana [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 10
Duke Energy Indiana [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 5
Duke Energy Indiana [Member] | 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	$ 17
Piedmont Natural Gas [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, remaining performance obligation, amount	$ 17
Piedmont Natural Gas [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 69
Piedmont Natural Gas [Member] | 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, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation, amount	$ 64
Piedmont Natural Gas [Member] | 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
Revenue, remaining performance obligation, amount	$ 64
Piedmont Natural Gas [Member] | 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
Revenue, remaining performance obligation, amount	$ 61
Piedmont Natural Gas [Member] | 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
Revenue, remaining performance obligation, amount	$ 430
Piedmont Natural Gas [Member] | 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	$ 705

Revenue (Disaggregation of Reve

Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 6,792	$ 6,451	$ 18,485	$ 17,845
Revenue from sources other than contracts with customers	148	177	491	561
Total operating revenues	6,940	6,628	18,976	18,406
Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,492	6,141	17,074	16,413
Total operating revenues	6,569	6,253	17,357	16,783
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,923	2,729	7,597	7,264
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,885	1,763	4,896	4,619
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	869	835	2,339	2,235
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	617	589	1,685	1,737
Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	198	225	557	558
Gas Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	223	233	1,236	1,244
Total operating revenues	225	232	1,239	1,229
Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	113	116	673	682
Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	68	66	359	354
Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	26	28	103	107
Gas Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	23	101	101
Commercial Renewables [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	69	61	157	141
Total operating revenues	138	127	362	347
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8	16	18	47
Total operating revenues	8	16	18	47
Duke Energy Carolinas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,140	2,051	5,535	5,391
Revenue from sources other than contracts with customers	22	39	84	134
Total operating revenues	2,162	2,090	5,619	5,525
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,140	2,051	5,535	5,391
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	892	823	2,331	2,263
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	687	635	1,714	1,608
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	372	352	927	893
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	113	132	341	366
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	76	109	222	261
Progress Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,167	2,977	8,334	7,922
Revenue from sources other than contracts with customers	75	68	224	197
Total operating revenues	3,242	3,045	8,558	8,119
Progress Energy [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,167	2,977	8,334	7,922
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,522	1,425	3,879	3,636
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	843	800	2,225	2,109
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	255	246	708	678
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	429	372	1,133	1,140
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	118	134	389	359
Duke Energy Progress [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,651	1,547	4,446	4,234
Revenue from sources other than contracts with customers	37	35	113	99
Total operating revenues	1,688	1,582	4,559	4,333
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,651	1,547	4,446	4,234
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	625	572	1,657	1,540
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	399	373	1,044	972
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	189	177	514	481
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	368	335	992	1,019
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	70	90	239	222
Duke Energy Florida [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,516	1,430	3,888	3,688
Revenue from sources other than contracts with customers	32	32	99	92
Total operating revenues	1,548	1,462	3,987	3,780
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,516	1,430	3,888	3,688
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	897	853	2,222	2,096
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	444	427	1,181	1,137
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	66	69	194	197
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	61	37	141	121
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	48	44	150	137
Duke Energy Ohio [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	494	466	1,454	1,435
Revenue from sources other than contracts with customers	(5)	3	(1)	17
Total operating revenues	489	469	1,453	1,452
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	413	371	1,102	1,040
Total operating revenues	408	373	1,099	1,055
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	215	203	563	564
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	127	112	335	318
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	40	33	109	96
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	3	36	5
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18	20	59	57
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	81	83	352	359
Total operating revenues	81	84	354	361
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	53	59	229	236
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	21	20	96	97
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	3	14	13
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	1	13	13
Duke Energy Ohio [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		12		36
Duke Energy Indiana [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	808	809	2,281	2,245
Revenue from sources other than contracts with customers	(1)	10	8	43
Total operating revenues	807	819	2,289	2,288
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	808	809	2,281	2,245
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	294	279	825	802
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	225	218	619	584
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	204	202	595	567
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	63	81	176	226
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22	29	66	66
Piedmont Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	157	162	924	924
Revenue from sources other than contracts with customers	11	10	32	16
Total operating revenues	168	172	956	940
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	157	162	924	924
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	59	57	443	446
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47	46	263	257
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	25	24	91	93
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Power Generation [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	13	39	40
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 13	$ 22	$ 88	$ 88

Revenue (Unbilled Revenues) (De

Revenue (Unbilled Revenues) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 831	$ 896
Duke Energy Carolinas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	312	313
Progress Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	265	244
Duke Energy Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	141	148
Duke Energy Florida [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	124	96
Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	2	2
Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	19	23
Piedmont Natural Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	2	73
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	74	86
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 124	$ 128

Stockholders' Equity (Earnings

Stockholders' Equity (Earnings Per Share Data) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Class of Stock [Line Items]
Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities	$ 1,324	$ 1,077	$ 3,041	$ 2,199
Weighted average common shares outstanding – basic (in shares)	729	713	728	705
Equity Forwards (in shares)		1		1
Weighted average common shares outstanding – diluted (in shares)	729	714	728	706
Basic (in usd per share)	$ 1.82	$ 1.51	$ 4.18	$ 3.12
Diluted (in usd per share)	$ 1.82	$ 1.51	$ 4.18	$ 3.11
Potentially dilutive items excluded from the calculation (in shares)	2	2	2	2
Common Stock [Member]
Class of Stock [Line Items]
Dividends declared per common share (in usd per share)	$ 0.945	$ 0.9275	$ 2.800	$ 2.7075
Depositary Share [Member]
Class of Stock [Line Items]
Dividends declared on preferred stock per depositary share (in usd per share)	$ 0.359		$ 0.667

Stockholders' Equity (Equity Se

Stockholders' Equity (Equity Securities Offering) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Feb. 20, 2018	Apr. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	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	$ 1,000
Proceeds from the issuance of common stock							$ 41	$ 834
Stock issued during period, shares, DRIP							1.4		2.2
Stock issued during period, value, DRIP							$ 120		$ 174
ATM [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares, Issued				2.6					2.6
Proceeds from the issuance of common stock				$ 195
ATM [Member] | Wells Fargo Bank [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered					1.3	1.6
Forward contract indexed to issuer's equity, forward rate per share						$ 86.23
ATM [Member] | JPMorgan Chase [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered			1.1
Forward contract indexed to issuer's equity, forward rate per share			$ 89.83
ATM [Member] | Citibank [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered		1.1			1.3
Forward contract indexed to issuer's equity, forward rate per share		$ 88.82
Equity Forwards [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered										21.3
Settlement alternative, shares										21.3
Shares, Issued				10.6	10.6				10.6
Proceeds from the issuance of common stock				$ 766	$ 781

Stockholders' Equity (Preferred

Stockholders' Equity (Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 16, 2024	Sep. 12, 2019	Mar. 29, 2019	Sep. 30, 2019	Jun. 15, 2024	Dec. 31, 2018
Class of Stock [Line Items]
Proceeds from the issuance of preferred stock, net of issuance costs		$ 990	$ 973	$ 1,963
Current maturities of long-term debt				$ 3,096		$ 3,406
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Shares issued (in shares)			40,000,000
Preferred stock, par value (in usd per share)			$ 0.001	$ 0.001
Price per share (in usd per share)			25
Liquidation preference per share (in usd per share)			$ 25
Cumulative dividend rate per annum			5.75%
Redemption price (in usd per share)				25.50
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Shares issued (in shares)		1,000,000
Preferred stock, par value (in usd per share)				$ 0.001
Price per share (in usd per share)		$ 1,000
Liquidation preference per share (in usd per share)		$ 1,000
Cumulative dividend rate per annum		4.875%
Redemption price (in usd per share)		$ 1,020
Forecast [Member]
Class of Stock [Line Items]
Redemption price (in usd per share)					$ 25
Forecast [Member] | Series B Preferred Stock [Member]
Class of Stock [Line Items]
Cumulative dividend rate per annum	3.388%
Parent Company [Member] | Debt Maturing September 2019, 5.050% Coupon [Member] | Unsecured Debt [Member]
Class of Stock [Line Items]
Current maturities of long-term debt				$ 500

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2019	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Remeasurement gain (loss) recognized		$ 18
Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.20%	3.50%
Cash balance interest crediting rate	4.00%	4.00%
Remeasurement gain (loss) recognized	$ 136
Increase (decrease) in plan assets	10	$ 275
Increase in projected benefit obligation	126	257
Settlement charge	16	69
Duke Energy Carolinas [Member] | Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	6	43
Duke Energy Progress [Member] | Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	3	16
Duke Energy Florida [Member] | Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	2	3
Duke Energy Indiana [Member] | Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	1	3
Duke Energy Ohio [Member] | Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge		1
Piedmont Natural Gas [Member] | Duke Energy RCBP [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	$ 3	$ 3

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - Qualified Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 42	$ 47	$ 116	$ 137
Interest cost on projected benefit obligation	77	74	242	224
Expected return on plan assets	(140)	(140)	(426)	(420)
Amortization of actuarial loss (gain)	28	33	77	99
Amortization of prior service (credit) cost	(8)	(8)	(24)	(24)
Net periodic costs	(1)	6	(15)	16
Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	13	15	37	45
Interest cost on projected benefit obligation	17	18	58	54
Expected return on plan assets	(36)	(37)	(111)	(111)
Amortization of actuarial loss (gain)	6	7	17	21
Amortization of prior service (credit) cost	(2)	(2)	(6)	(6)
Net periodic costs	(2)	1	(5)	3
Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	13	13	34	39
Interest cost on projected benefit obligation	24	24	76	70
Expected return on plan assets	(45)	(45)	(134)	(133)
Amortization of actuarial loss (gain)	10	11	28	33
Amortization of prior service (credit) cost	(1)	(1)	(2)	(3)
Net periodic costs	1	2	2	6
Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	7	7	19	22
Interest cost on projected benefit obligation	10	10	34	31
Expected return on plan assets	(22)	(21)	(66)	(63)
Amortization of actuarial loss (gain)	4	6	10	16
Amortization of prior service (credit) cost			(1)	(1)
Net periodic costs	(1)	2	(4)	5
Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	5	5	15	16
Interest cost on projected benefit obligation	14	13	41	38
Expected return on plan assets	(22)	(23)	(66)	(69)
Amortization of actuarial loss (gain)	6	6	18	18
Amortization of prior service (credit) cost			(1)	(1)
Net periodic costs	3	1	7	2
Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	2	3	4
Interest cost on projected benefit obligation	5	4	14	13
Expected return on plan assets	(7)	(7)	(21)	(21)
Amortization of actuarial loss (gain)	2	1	3	3
Net periodic costs	1		(1)	(1)
Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	2	6	7
Interest cost on projected benefit obligation	6	6	19	18
Expected return on plan assets	(11)	(10)	(32)	(31)
Amortization of actuarial loss (gain)	3	2	6	6
Amortization of prior service (credit) cost			(1)
Net periodic costs			(2)
Piedmont Natural Gas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	2	4	6
Interest cost on projected benefit obligation	2	3	8	9
Expected return on plan assets	(5)	(6)	(16)	(18)
Amortization of actuarial loss (gain)	2	3	5	9
Amortization of prior service (credit) cost	(2)	(3)	(7)	(9)
Net periodic costs	$ (2)	$ (1)	$ (6)	$ (3)

Employee Benefit Plans - Summar

Employee Benefit Plans - Summary of Contributions (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributions made	$ 77
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	7
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	57
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	4
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	53
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	2
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	2
Piedmont Natural Gas [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions made	$ 1

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	12.40%	13.70%	12.50%	17.00%
Duke Energy Carolinas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	16.70%	22.60%	17.70%	22.30%
Progress Energy [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	15.30%	18.80%	16.20%	17.00%
Duke Energy Progress [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	14.70%	20.60%	16.10%	18.40%
Duke Energy Florida [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	16.50%	15.00%	18.00%	16.30%
Duke Energy Ohio [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	12.90%	16.00%	15.20%	16.00%
Duke Energy Indiana [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	23.20%	22.70%	23.70%	24.70%
Piedmont Natural Gas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	35.70%	34.40%	18.50%	20.60%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) $ in Millions	Oct. 23, 2019USD ($)
Subsequent Event [Member] | AMT Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Tax refund	$ 573