Duke Energy Indiana 10-Q 9 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document Information [Line Items]
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	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		728,046,950
Trading Symbol	DUK
Entity Emerging Growth Company	false
Entity Small Business	false
Duke Energy Carolinas [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false
Progress Energy [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false
Duke Energy Progress [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false
Duke Energy Florida [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false
Duke Energy Ohio [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false
Duke Energy Indiana [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false
Piedmont Natural Gas [Member]
Document Information [Line Items]
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 Emerging Growth Company	false
Entity Small Business	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Revenues
Regulated electric	$ 5,285	$ 5,284
Regulated natural gas	728	700
Nonregulated electric and other	150	151
Total operating revenues	6,163	6,135
Operating Expenses
Operation, maintenance and other	1,419	1,464
Depreciation and amortization	1,089	967
Property and other taxes	343	316
Impairment charges		43
Total operating expenses	4,787	4,779
Losses on Sales of Other Assets and Other, net	(3)	(100)
Operating Income	1,373	1,256
Other Income and Expenses
Equity in earnings (losses) of unconsolidated affiliates	43	(24)
Other income and expenses, net	115	86
Total other income and expenses	158	62
Interest Expense	543	515
Income Before Income Taxes	988	803
Income Tax Expense	95	181
Net Income	893	622
Less: Net (Loss) Income Attributable to Noncontrolling Interests	(7)	2
Net Income Attributable to Duke Energy Corporation	900	620
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments		1
Net unrealized (losses) gains on cash flow hedges	(17)	12
Reclassification into earnings from cash flow hedges	1	1
Unrealized gains (losses) on available-for-sale securities	4	(3)
Other Comprehensive (Loss) Income, net of tax	(12)	11
Comprehensive Income	881	633
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests	(7)	2
Comprehensive Income Attributable to Duke Energy Corporation	$ 888	$ 631
Net income attributable to Duke Energy Corporation common stockholders
Basic and Diluted (in usd per share)	$ 1.24	$ 0.88
Weighted average shares outstanding
Basic and Diluted (in shares)	727	701
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 1,744	$ 1,763
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	472	473
Operation, maintenance and other	440	451
Depreciation and amortization	317	272
Property and other taxes	80	72
Impairment charges		13
Total operating expenses	1,309	1,281
Operating Income	435	482
Other Income and Expenses
Total other income and expenses	31	39
Interest Expense	110	107
Income Before Income Taxes	356	414
Income Tax Expense	63	91
Net Income Attributable to Duke Energy Corporation	293	323
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges	0	1
Other Comprehensive (Loss) Income, net of tax		1
Comprehensive Income Attributable to Duke Energy Corporation	293	324
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,572	2,576
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	925	976
Operation, maintenance and other	567	623
Depreciation and amortization	455	384
Property and other taxes	137	123
Impairment charges		29
Total operating expenses	2,084	2,135
Losses on Sales of Other Assets and Other, net		6
Operating Income	488	447
Other Income and Expenses
Total other income and expenses	31	35
Interest Expense	219	209
Income Before Income Taxes	300	273
Income Tax Expense	52	36
Net Income	248	237
Less: Net (Loss) Income Attributable to Noncontrolling Interests	(1)	2
Net Income Attributable to Duke Energy Corporation	249	235
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	1	0
Net unrealized (losses) gains on cash flow hedges	2	2
Other Comprehensive (Loss) Income, net of tax	3	2
Comprehensive Income	251	239
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests	(1)	2
Comprehensive Income Attributable to Duke Energy Corporation	252	237
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,484	1,460
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	515	509
Operation, maintenance and other	335	381
Depreciation and amortization	290	235
Property and other taxes	44	35
Impairment charges		32
Total operating expenses	1,184	1,192
Losses on Sales of Other Assets and Other, net		1
Operating Income	300	269
Other Income and Expenses
Total other income and expenses	24	18
Interest Expense	77	81
Income Before Income Taxes	247	206
Income Tax Expense	44	29
Net Income Attributable to Duke Energy Corporation	203	177
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation	203	177
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,086	1,115
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	410	467
Operation, maintenance and other	230	237
Depreciation and amortization	165	150
Property and other taxes	93	88
Total operating expenses	898	942
Operating Income	188	173
Other Income and Expenses
Total other income and expenses	13	21
Interest Expense	82	71
Income Before Income Taxes	119	123
Income Tax Expense	23	20
Net Income Attributable to Duke Energy Corporation	96	103
Other Comprehensive Income (Loss), net of tax
Unrealized gains (losses) on available-for-sale securities	1
Other Comprehensive (Loss) Income, net of tax	1	0
Comprehensive Income Attributable to Duke Energy Corporation	97	103
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	355	336
Regulated natural gas	176	174
Nonregulated electric and other		14
Total operating revenues	531	524
Operating Expenses
Operation, maintenance and other	132	131
Depreciation and amortization	64	70
Property and other taxes	84	77
Total operating expenses	427	439
Losses on Sales of Other Assets and Other, net		(106)
Operating Income	104	(21)
Other Income and Expenses
Total other income and expenses	9	6
Interest Expense	30	22
Income Before Income Taxes	83	(37)
Income Tax Expense	14	(12)
Net Income Attributable to Duke Energy Corporation	69	(25)
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation	69	(25)
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	768	731
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	257	232
Operation, maintenance and other	189	181
Depreciation and amortization	131	130
Property and other taxes	19	20
Total operating expenses	596	563
Losses on Sales of Other Assets and Other, net	(3)
Operating Income	169	168
Other Income and Expenses
Total other income and expenses	19	7
Interest Expense	43	40
Income Before Income Taxes	145	135
Income Tax Expense	35	35
Net Income Attributable to Duke Energy Corporation	110	100
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation	110	100
Piedmont Natural Gas [Member]
Operating Revenues
Total operating revenues	579	553
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	273	259
Operation, maintenance and other	80	82
Depreciation and amortization	42	39
Property and other taxes	12	12
Total operating expenses	407	392
Operating Income	172	161
Other Income and Expenses
Equity in earnings (losses) of unconsolidated affiliates	2	2
Other income and expenses, net	4	3
Total other income and expenses	6	5
Interest Expense	22	21
Income Before Income Taxes	156	145
Income Tax Expense	34	35
Net Income Attributable to Duke Energy Corporation	122	110
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Duke Energy Corporation	122	110
Electricity, US Regulated [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	93	92
Electricity, Nonregulated [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas		15
Electricity [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	1,609	1,676
Natural Gas [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	327	313
Natural Gas [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	$ 54	$ 54

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net Income	$ 893	$ 622
Other Comprehensive Income, net of tax
Pension and OPEB adjustments		1
Net unrealized (losses) gains on cash flow hedges	(17)	12
Reclassification into earnings from cash flow hedges	1	1
Unrealized gains (losses) on available-for-sale securities	4	(3)
Other Comprehensive (Loss) Income, net of tax	(12)	11
Comprehensive Income	881	633
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests	(7)	2
Comprehensive Income Attributable to Duke Energy Corporation	$ 888	$ 631

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 377	$ 442
Receivables (net of allowance for doubtful accounts)	775	962
Receivables of VIEs (net of allowance for doubtful accounts)	1,981	2,172
Inventory	3,102	3,084
Regulatory assets (includes amounts related to VIEs)	1,957	2,005
Other (includes amounts related to VIEs)	976	1,049
Total current assets	9,168	9,714
Property, Plant and Equipment
Cost	139,377	134,458
Accumulated depreciation and amortization	(43,992)	(43,126)
Generation facilities to be retired, net	336	362
Net property, plant and equipment	95,721	91,694
Operating Lease Right-of-Use Assets, net	1,698
Other Noncurrent Assets
Goodwill	19,303	19,303
Regulatory assets	13,301	13,617
Nuclear decommissioning trust funds	7,374	6,720
Investments in equity method unconsolidated affiliates	1,602	1,409
Other (includes amounts related to VIEs)	2,969	2,935
Total other noncurrent assets	44,549	43,984
Total Assets	151,136	145,392
Current Liabilities
Accounts payable	2,538	3,487
Notes payable and commercial paper	3,029	3,410
Taxes accrued	470	577
Interest accrued	544	559
Current maturities of long-term debt (includes amounts related to VIEs)	2,501	3,406
Asset retirement obligations	779	919
Regulatory liabilities	611	598
Other	1,810	2,085
Total current liabilities	12,282	15,041
Long-Term Debt (includes amounts related to VIEs)	53,681	51,123
Operating Lease Liabilities	1,488
Other Noncurrent Liabilities
Deferred income taxes	8,040	7,806
Asset retirement obligations	12,256	9,548
Regulatory liabilities	15,212	14,834
Accrued pension and other post-retirement benefit costs	974	988
Investment tax credits	571	568
Other (includes amounts related to VIEs)	1,587	1,650
Total other noncurrent liabilities	38,640	35,394
Commitments and Contingencies
Equity
Preferred stock	974
Common stock	1	1
Additional paid-in capital	40,823	40,795
Retained earnings	3,360	3,113
Accumulated other comprehensive loss	(128)	(92)
Total Duke Energy Corporation stockholders' equity	45,030	43,817
Noncontrolling interests	15	17
Total equity	45,045	43,834
Total Liabilities and Equity	151,136	145,392
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents		33
Receivables (net of allowance for doubtful accounts)	166	219
Receivables of VIEs (net of allowance for doubtful accounts)	630	699
Receivables from affiliated companies	88	182
Inventory	1,007	948
Regulatory assets (includes amounts related to VIEs)	560	520
Other (includes amounts related to VIEs)	31	72
Total current assets	2,482	2,673
Property, Plant and Equipment
Cost	46,929	44,741
Accumulated depreciation and amortization	(15,899)	(15,496)
Net property, plant and equipment	31,030	29,245
Operating Lease Right-of-Use Assets, net	146
Other Noncurrent Assets
Regulatory assets	3,429	3,457
Nuclear decommissioning trust funds	3,913	3,558
Other (includes amounts related to VIEs)	1,027	1,027
Total other noncurrent assets	8,369	8,042
Total Assets	42,027	39,960
Current Liabilities
Accounts payable	643	988
Accounts payable to affiliated companies	248	230
Notes payable to affiliated companies	745	439
Taxes accrued	80	171
Interest accrued	134	102
Current maturities of long-term debt (includes amounts related to VIEs)	7	6
Asset retirement obligations	209	290
Regulatory liabilities	200	199
Other	415	571
Total current liabilities	2,681	2,996
Long-Term Debt (includes amounts related to VIEs)	10,658	10,633
Long-Term Debt Payable to Affiliated Companies	300	300
Operating Lease Liabilities	123
Other Noncurrent Liabilities
Deferred income taxes	3,769	3,689
Asset retirement obligations	5,219	3,659
Regulatory liabilities	6,325	5,999
Accrued pension and other post-retirement benefit costs	97	99
Investment tax credits	235	231
Other (includes amounts related to VIEs)	645	671
Total other noncurrent liabilities	16,290	14,348
Equity
Member's equity	11,982	11,689
Accumulated other comprehensive loss	(7)	(6)
Total member's equity	11,975	11,683
Total Liabilities and Equity	42,027	39,960
Progress Energy [Member]
Current Assets
Cash and cash equivalents	45	67
Receivables (net of allowance for doubtful accounts)	128	220
Receivables of VIEs (net of allowance for doubtful accounts)	817	909
Receivables from affiliated companies	46	168
Notes receivable from affiliated companies	31
Inventory	1,464	1,459
Regulatory assets (includes amounts related to VIEs)	1,076	1,137
Other (includes amounts related to VIEs)	143	125
Total current assets	3,750	4,085
Property, Plant and Equipment
Cost	52,309	50,260
Accumulated depreciation and amortization	(16,646)	(16,398)
Generation facilities to be retired, net	336	362
Net property, plant and equipment	35,999	34,224
Operating Lease Right-of-Use Assets, net	835
Other Noncurrent Assets
Goodwill	3,655	3,655
Regulatory assets	6,358	6,564
Nuclear decommissioning trust funds	3,461	3,162
Other (includes amounts related to VIEs)	1,029	974
Total other noncurrent assets	14,503	14,355
Total Assets	55,087	52,664
Current Liabilities
Accounts payable	781	1,172
Accounts payable to affiliated companies	266	360
Notes payable to affiliated companies	1,605	1,235
Taxes accrued	135	109
Interest accrued	213	246
Current maturities of long-term debt (includes amounts related to VIEs)	825	1,672
Asset retirement obligations	456	514
Regulatory liabilities	259	280
Other	778	821
Total current liabilities	5,318	6,409
Long-Term Debt (includes amounts related to VIEs)	18,276	17,089
Long-Term Debt Payable to Affiliated Companies	150	150
Operating Lease Liabilities	748
Other Noncurrent Liabilities
Deferred income taxes	4,064	3,941
Asset retirement obligations	6,050	4,897
Regulatory liabilities	5,116	5,049
Accrued pension and other post-retirement benefit costs	516	521
Other (includes amounts related to VIEs)	341	351
Total other noncurrent liabilities	16,087	14,759
Equity
Additional paid-in capital	9,143	9,143
Retained earnings	5,386	5,131
Accumulated other comprehensive loss	(23)	(20)
Total Duke Energy Corporation stockholders' equity	14,506	14,254
Noncontrolling interests	2	3
Total equity	14,508	14,257
Total Liabilities and Equity	55,087	52,664
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	30	23
Receivables (net of allowance for doubtful accounts)	42	75
Receivables of VIEs (net of allowance for doubtful accounts)	495	547
Receivables from affiliated companies	28	23
Notes receivable from affiliated companies	38
Inventory	959	954
Regulatory assets (includes amounts related to VIEs)	622	703
Other (includes amounts related to VIEs)	45	62
Total current assets	2,259	2,387
Property, Plant and Equipment
Cost	33,188	31,459
Accumulated depreciation and amortization	(11,635)	(11,423)
Generation facilities to be retired, net	336	362
Net property, plant and equipment	21,889	20,398
Operating Lease Right-of-Use Assets, net	388
Other Noncurrent Assets
Regulatory assets	4,041	4,111
Nuclear decommissioning trust funds	2,744	2,503
Other (includes amounts related to VIEs)	627	612
Total other noncurrent assets	7,412	7,226
Total Assets	31,948	30,011
Current Liabilities
Accounts payable	363	660
Accounts payable to affiliated companies	221	278
Notes payable to affiliated companies		294
Taxes accrued	49	53
Interest accrued	87	116
Current maturities of long-term debt (includes amounts related to VIEs)	5	603
Asset retirement obligations	452	509
Regulatory liabilities	176	178
Other	346	408
Total current liabilities	1,699	3,099
Long-Term Debt (includes amounts related to VIEs)	8,893	7,451
Long-Term Debt Payable to Affiliated Companies	150	150
Operating Lease Liabilities	361
Other Noncurrent Liabilities
Deferred income taxes	2,172	2,119
Asset retirement obligations	5,471	4,311
Regulatory liabilities	4,093	3,955
Accrued pension and other post-retirement benefit costs	235	237
Investment tax credits	141	142
Other (includes amounts related to VIEs)	89	106
Total other noncurrent liabilities	12,201	10,870
Equity
Total member's equity	8,644	8,441
Total Liabilities and Equity	31,948	30,011
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	8	36
Receivables (net of allowance for doubtful accounts)	85	143
Receivables of VIEs (net of allowance for doubtful accounts)	322	362
Receivables from affiliated companies	34	28
Inventory	505	504
Regulatory assets (includes amounts related to VIEs)	454	434
Other (includes amounts related to VIEs)	55	46
Total current assets	1,463	1,553
Property, Plant and Equipment
Cost	19,111	18,792
Accumulated depreciation and amortization	(5,003)	(4,968)
Net property, plant and equipment	14,108	13,824
Operating Lease Right-of-Use Assets, net	447
Other Noncurrent Assets
Regulatory assets	2,316	2,454
Nuclear decommissioning trust funds	717	659
Other (includes amounts related to VIEs)	318	311
Total other noncurrent assets	3,351	3,424
Total Assets	19,369	18,801
Current Liabilities
Accounts payable	417	511
Accounts payable to affiliated companies	29	91
Notes payable to affiliated companies	399	108
Taxes accrued	94	74
Interest accrued	74	75
Current maturities of long-term debt (includes amounts related to VIEs)	470	270
Asset retirement obligations	4	5
Regulatory liabilities	83	102
Other	426	406
Total current liabilities	1,996	1,642
Long-Term Debt (includes amounts related to VIEs)	6,795	7,051
Operating Lease Liabilities	387
Other Noncurrent Liabilities
Deferred income taxes	2,051	1,986
Asset retirement obligations	579	586
Regulatory liabilities	1,023	1,094
Accrued pension and other post-retirement benefit costs	251	254
Other (includes amounts related to VIEs)	95	93
Total other noncurrent liabilities	3,999	4,013
Equity
Member's equity	6,193	6,097
Accumulated other comprehensive loss	(1)	(2)
Total member's equity	6,192	6,095
Total Liabilities and Equity	19,369	18,801
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	17	21
Receivables (net of allowance for doubtful accounts)	99	102
Receivables from affiliated companies	79	114
Notes receivable from affiliated companies	463
Inventory	111	126
Regulatory assets (includes amounts related to VIEs)	59	33
Other (includes amounts related to VIEs)	25	24
Total current assets	853	420
Property, Plant and Equipment
Cost	9,542	9,360
Accumulated depreciation and amortization	(2,739)	(2,717)
Net property, plant and equipment	6,803	6,643
Operating Lease Right-of-Use Assets, net	22
Other Noncurrent Assets
Goodwill	920	920
Regulatory assets	501	531
Other (includes amounts related to VIEs)	45	41
Total other noncurrent assets	1,466	1,492
Total Assets	9,144	8,555
Current Liabilities
Accounts payable	288	316
Accounts payable to affiliated companies	70	78
Notes payable to affiliated companies	38	274
Taxes accrued	157	202
Interest accrued	43	22
Current maturities of long-term debt (includes amounts related to VIEs)	551	551
Asset retirement obligations	6	6
Regulatory liabilities	51	57
Other	69	74
Total current liabilities	1,273	1,580
Long-Term Debt (includes amounts related to VIEs)	2,384	1,589
Long-Term Debt Payable to Affiliated Companies	25	25
Operating Lease Liabilities	21
Other Noncurrent Liabilities
Deferred income taxes	842	817
Asset retirement obligations	87	87
Regulatory liabilities	839	840
Accrued pension and other post-retirement benefit costs	80	79
Other (includes amounts related to VIEs)	79	93
Total other noncurrent liabilities	1,927	1,916
Equity
Common stock	762	762
Additional paid-in capital	2,776	2,776
Retained earnings	(24)	(93)
Total Duke Energy Corporation stockholders' equity	3,514	3,445
Total Liabilities and Equity	9,144	8,555
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	20	24
Receivables (net of allowance for doubtful accounts)	50	52
Receivables from affiliated companies	102	122
Inventory	435	422
Regulatory assets (includes amounts related to VIEs)	151	175
Other (includes amounts related to VIEs)	23	35
Total current assets	781	830
Property, Plant and Equipment
Cost	15,633	15,443
Accumulated depreciation and amortization	(5,021)	(4,914)
Net property, plant and equipment	10,612	10,529
Operating Lease Right-of-Use Assets, net	61
Other Noncurrent Assets
Regulatory assets	981	982
Other (includes amounts related to VIEs)	201	194
Total other noncurrent assets	1,182	1,176
Total Assets	12,636	12,535
Current Liabilities
Accounts payable	198	200
Accounts payable to affiliated companies	72	83
Notes payable to affiliated companies	136	167
Taxes accrued	63	43
Interest accrued	53	58
Current maturities of long-term debt (includes amounts related to VIEs)	3	63
Asset retirement obligations	108	109
Regulatory liabilities	27	25
Other	92	107
Total current liabilities	752	855
Long-Term Debt (includes amounts related to VIEs)	3,569	3,569
Long-Term Debt Payable to Affiliated Companies	150	150
Operating Lease Liabilities	57
Other Noncurrent Liabilities
Deferred income taxes	1,050	1,009
Asset retirement obligations	611	613
Regulatory liabilities	1,709	1,722
Accrued pension and other post-retirement benefit costs	113	115
Investment tax credits	147	147
Other (includes amounts related to VIEs)	29	16
Total other noncurrent liabilities	3,659	3,622
Equity
Total member's equity	4,449	4,339
Total Liabilities and Equity	12,636	12,535
Piedmont Natural Gas [Member]
Current Assets
Receivables (net of allowance for doubtful accounts)	241	266
Receivables from affiliated companies	10	22
Inventory	25	70
Regulatory assets (includes amounts related to VIEs)	28	54
Other (includes amounts related to VIEs)	19	19
Total current assets	323	431
Property, Plant and Equipment
Cost	7,676	7,486
Accumulated depreciation and amortization	(1,587)	(1,575)
Net property, plant and equipment	6,089	5,911
Operating Lease Right-of-Use Assets, net	27
Other Noncurrent Assets
Goodwill	49	49
Regulatory assets	289	303
Investments in equity method unconsolidated affiliates	64	64
Other (includes amounts related to VIEs)	51	52
Total other noncurrent assets	453	468
Total Assets	6,892	6,810
Current Liabilities
Accounts payable	161	203
Accounts payable to affiliated companies	34	38
Notes payable to affiliated companies	201	198
Taxes accrued	35	84
Interest accrued	25	31
Current maturities of long-term debt (includes amounts related to VIEs)	350	350
Regulatory liabilities	75	37
Other	49	58
Total current liabilities	930	999
Long-Term Debt (includes amounts related to VIEs)	1,788	1,788
Operating Lease Liabilities	26
Other Noncurrent Liabilities
Deferred income taxes	575	551
Asset retirement obligations	19	19
Regulatory liabilities	1,179	1,181
Accrued pension and other post-retirement benefit costs	4	4
Other (includes amounts related to VIEs)	158	177
Total other noncurrent liabilities	1,935	1,932
Equity
Common stock	1,160	1,160
Retained earnings	1,053	931
Total Duke Energy Corporation stockholders' equity	2,213	2,091
Total Liabilities and Equity	$ 6,892	$ 6,810

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts - receivables	$ 19	$ 16
Regulatory assets, current	1,957	2,005
Other, current assets	976	1,049
Regulatory assets, noncurrent	13,301	13,617
Other, noncurrent assets	2,969	2,935
Current maturities of long-term debt	2,501	3,406
Long-Term Debt	$ 53,681	$ 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	728,000,000	727,000,000
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
Other	$ 1,587	$ 1,650
Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	56	55
Regulatory assets, current	52	52
Other, current assets	152	162
Regulatory assets, noncurrent	1,032	1,041
Other, noncurrent assets	280	261
Current maturities of long-term debt	227	227
Long-Term Debt	4,065	3,998
Other	212	212
Duke Energy Carolinas [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	560	520
Other, current assets	31	72
Regulatory assets, noncurrent	3,429	3,457
Other, noncurrent assets	1,027	1,027
Current maturities of long-term debt	7	6
Long-Term Debt	10,658	10,633
Other	645	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	5	5
Regulatory assets, current	1,076	1,137
Other, current assets	143	125
Regulatory assets, noncurrent	6,358	6,564
Other, noncurrent assets	1,029	974
Current maturities of long-term debt	825	1,672
Long-Term Debt	$ 18,276	$ 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	$ 341	$ 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	12	39
Regulatory assets, noncurrent	1,032	1,041
Current maturities of long-term debt	54	53
Long-Term Debt	1,657	1,636
Duke Energy Progress [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	622	703
Other, current assets	45	62
Regulatory assets, noncurrent	4,041	4,111
Other, noncurrent assets	627	612
Current maturities of long-term debt	5	603
Long-Term Debt	8,893	7,451
Other	89	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	454	434
Other, current assets	55	46
Regulatory assets, noncurrent	2,316	2,454
Other, noncurrent assets	318	311
Current maturities of long-term debt	470	270
Long-Term Debt	6,795	7,051
Other	95	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	12	39
Regulatory assets, noncurrent	1,032	1,041
Current maturities of long-term debt	54	53
Long-Term Debt	1,332	1,336
Duke Energy Ohio [Member]
Allowance for doubtful accounts - receivables	3	2
Regulatory assets, current	59	33
Other, current assets	25	24
Regulatory assets, noncurrent	501	531
Other, noncurrent assets	45	41
Current maturities of long-term debt	551	551
Long-Term Debt	$ 2,384	$ 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	$ 79	$ 93
Duke Energy Indiana [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	151	175
Other, current assets	23	35
Regulatory assets, noncurrent	981	982
Other, noncurrent assets	201	194
Current maturities of long-term debt	3	63
Long-Term Debt	3,569	3,569
Other	29	16
Piedmont Natural Gas [Member]
Allowance for doubtful accounts - receivables	4	2
Regulatory assets, current	28	54
Other, current assets	19	19
Regulatory assets, noncurrent	289	303
Other, noncurrent assets	51	52
Current maturities of long-term debt	350	350
Long-Term Debt	$ 1,788	$ 1,788
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Other	$ 158	$ 177

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 893	$ 622
Net income (attributable to parent)	900	620
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,238	1,089
Equity component of AFUDC	(31)	(55)
Losses on sales of other assets	3	100
Impairment charges		43
Deferred income taxes	97	199
Equity in (earnings) losses of unconsolidated affiliates	(43)	24
Accrued pension and other post-retirement benefit costs	2	15
Contributions to qualified pension plans		(141)
Payments for asset retirement obligations	(152)	(122)
Payment for disposal of other assets		(105)
Other rate case adjustments		37
Provision for rate refunds	35	158
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	10	4
Receivables	388	64
Inventory	(31)	101
Other current assets	98	27
Increase (decrease) in
Accounts payable	(636)	(327)
Taxes accrued	(107)	(107)
Other current liabilities	(407)	(171)
Other assets	(158)	(59)
Other liabilities	40	(5)
Net cash provided by operating activities	1,239	1,391
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,536)	(2,087)
Contributions to equity method investments	(94)	(74)
Purchases of debt and equity securities	(860)	(958)
Proceeds from sales and maturities of debt and equity securities	851	930
Other	(74)	(75)
Net cash used in investing activities	(2,713)	(2,264)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	2,737	1,240
Proceeds from the issuance of preferred stock	974
Proceeds from the issuance of common stock	13	21
Payments for the redemption of long-term debt	(1,201)	(487)
Proceeds from the issuance of short-term debt with original maturities greater than 90 days	135	135
Payments for the redemption of short-term debt with original maturities greater than 90 days	(239)	(50)
Notes payable and commercial paper	(304)	706
Dividends paid	(649)	(599)
Other	(33)	(19)
Net cash provided by financing activities	1,433	947
Net (decrease) increase in cash, cash equivalents and restricted cash	(41)	74
Cash, cash equivalents and restricted cash at beginning of period	591	505
Cash, cash equivalents and restricted cash at end of period	550	579
Cash and cash equivalents at beginning of period	442
Cash and cash equivalents at end of period	377
Significant non-cash transactions:
Accrued capital expenditures	811	799
Non-cash dividends	27	26
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	293	323
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	388	347
Equity component of AFUDC	(9)	(21)
Impairment charges		13
Deferred income taxes	64	80
Accrued pension and other post-retirement benefit costs	(2)	1
Contributions to qualified pension plans		(46)
Payments for asset retirement obligations	(65)	(55)
Provision for rate refunds	19	61
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1
Receivables	124	19
Receivable from affiliated companies	94	(11)
Inventory	(59)	(9)
Other current assets	(35)	(144)
Increase (decrease) in
Accounts payable	(266)	(76)
Accounts payable to affiliated companies	18	50
Taxes accrued	(91)	(129)
Other current liabilities	(70)	(23)
Other assets	(29)	12
Other liabilities	(7)	(43)
Net cash provided by operating activities	368	349
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(721)	(621)
Purchases of debt and equity securities	(405)	(494)
Proceeds from sales and maturities of debt and equity securities	405	494
Other	(9)	(21)
Net cash used in investing activities	(730)	(642)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	25	991
Payments for the redemption of long-term debt	(1)	(401)
Notes payable to affiliated companies	306	(59)
Distributions to parent		(250)
Other	(1)	(1)
Net cash provided by financing activities	329	280
Net increase (decrease) in cash and cash equivalents	(33)	(13)
Cash and cash equivalents at beginning of period	33	16
Cash and cash equivalents at end of period		3
Significant non-cash transactions:
Accrued capital expenditures	221	267
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	248	237
Net income (attributable to parent)	249	235
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	546	439
Equity component of AFUDC	(15)	(26)
Losses on sales of other assets		(6)
Impairment charges		29
Deferred income taxes	82	71
Accrued pension and other post-retirement benefit costs	4	6
Contributions to qualified pension plans		(45)
Payments for asset retirement obligations	(75)	(55)
Other rate case adjustments		37
Provision for rate refunds	6	33
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1	4
Receivables	187	(33)
Receivable from affiliated companies	122	29
Inventory	(18)	55
Other current assets	35	(60)
Increase (decrease) in
Accounts payable	(196)	(53)
Accounts payable to affiliated companies	(94)	33
Taxes accrued	26	8
Other current liabilities	(196)	(82)
Other assets	(112)	(86)
Other liabilities	(10)	(8)
Net cash provided by operating activities	541	527
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,012)	(762)
Purchases of debt and equity securities	(409)	(406)
Proceeds from sales and maturities of debt and equity securities	405	411
Notes receivable from affiliated companies	(31)	127
Other	(45)	(40)
Net cash used in investing activities	(1,092)	(670)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,295
Payments for the redemption of long-term debt	(1,132)	(80)
Notes payable to affiliated companies	370	177
Other	1	(2)
Net cash provided by financing activities	534	95
Net (decrease) increase in cash, cash equivalents and restricted cash	(17)	(48)
Cash, cash equivalents and restricted cash at beginning of period	112	87
Cash, cash equivalents and restricted cash at end of period	95	39
Cash and cash equivalents at beginning of period	67
Cash and cash equivalents at end of period	45
Significant non-cash transactions:
Accrued capital expenditures	310	316
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	203	177
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	336	284
Equity component of AFUDC	(14)	(14)
Losses on sales of other assets		(1)
Impairment charges		32
Deferred income taxes	33	42
Accrued pension and other post-retirement benefit costs		4
Contributions to qualified pension plans		(25)
Payments for asset retirement obligations	(68)	(44)
Other rate case adjustments		37
Provision for rate refunds	6	33
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(3)	2
Receivables	87	(31)
Receivable from affiliated companies	(5)	(2)
Inventory	(5)	15
Other current assets	96	(88)
Increase (decrease) in
Accounts payable	(196)	(39)
Accounts payable to affiliated companies	(57)	29
Taxes accrued	(4)	(28)
Other current liabilities	(109)	(64)
Other assets	(45)	18
Other liabilities	(9)	(5)
Net cash provided by operating activities	246	332
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(548)	(424)
Purchases of debt and equity securities	(315)	(284)
Proceeds from sales and maturities of debt and equity securities	308	281
Notes receivable from affiliated companies	(38)
Other	(20)	(30)
Net cash used in investing activities	(613)	(457)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,270
Payments for the redemption of long-term debt	(601)
Notes payable to affiliated companies	(294)	114
Other	(1)	(1)
Net cash provided by financing activities	374	113
Net increase (decrease) in cash and cash equivalents	7	(12)
Cash and cash equivalents at beginning of period	23	20
Cash and cash equivalents at end of period	30	8
Significant non-cash transactions:
Accrued capital expenditures	117	137
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	96	103
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	207	152
Equity component of AFUDC	(1)	(12)
Deferred income taxes	45	29
Accrued pension and other post-retirement benefit costs	3	1
Contributions to qualified pension plans		(20)
Payments for asset retirement obligations	(7)	(11)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	2	2
Receivables	55	(2)
Receivable from affiliated companies	(6)
Inventory	(13)	39
Other current assets	(35)	42
Increase (decrease) in
Accounts payable		(13)
Accounts payable to affiliated companies	(62)	8
Taxes accrued	20	38
Other current liabilities	(84)	(17)
Other assets	(66)	(107)
Other liabilities	(1)	(5)
Net cash provided by operating activities	153	227
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(422)	(338)
Purchases of debt and equity securities	(95)	(122)
Proceeds from sales and maturities of debt and equity securities	97	129
Notes receivable from affiliated companies		160
Other	(25)	(10)
Net cash used in investing activities	(445)	(181)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	25
Payments for the redemption of long-term debt	(81)	(80)
Notes payable to affiliated companies	291
Other	2
Net cash provided by financing activities	237	(80)
Net (decrease) increase in cash, cash equivalents and restricted cash	(55)	(34)
Cash, cash equivalents and restricted cash at beginning of period	75	53
Cash, cash equivalents and restricted cash at end of period	20	19
Cash and cash equivalents at beginning of period	36
Cash and cash equivalents at end of period	8
Significant non-cash transactions:
Accrued capital expenditures	193	179
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	69	(25)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	65	71
Equity component of AFUDC	(3)	(4)
Losses on sales of other assets		106
Deferred income taxes	20	(15)
Accrued pension and other post-retirement benefit costs		1
Payments for asset retirement obligations	(1)	(1)
Provision for rate refunds	4	16
(Increase) decrease in
Receivables	5	(1)
Receivable from affiliated companies	35	56
Inventory	15	25
Other current assets	(6)	19
Increase (decrease) in
Accounts payable	(5)	(27)
Accounts payable to affiliated companies	(8)	(95)
Taxes accrued	(45)	(45)
Other current liabilities	14	20
Other assets	(10)
Other liabilities	(4)	(13)
Net cash provided by operating activities	145	88
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(233)	(188)
Notes receivable from affiliated companies	(463)	14
Other	(11)	(14)
Net cash used in investing activities	(707)	(188)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	794
Notes payable to affiliated companies	(236)	101
Other		(1)
Net cash provided by financing activities	558	100
Net increase (decrease) in cash and cash equivalents	(4)
Cash and cash equivalents at beginning of period	21	12
Cash and cash equivalents at end of period	17	12
Significant non-cash transactions:
Accrued capital expenditures	68	64
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	110	100
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	132	131
Equity component of AFUDC	(4)	(4)
Losses on sales of other assets	3
Deferred income taxes	28	17
Accrued pension and other post-retirement benefit costs	1	2
Contributions to qualified pension plans		(8)
Payments for asset retirement obligations	(11)	(11)
Provision for rate refunds		26
(Increase) decrease in
Receivables	4
Receivable from affiliated companies	20	26
Inventory	(13)	(3)
Other current assets	19	(23)
Increase (decrease) in
Accounts payable	8	21
Accounts payable to affiliated companies	(11)	(5)
Taxes accrued	20	(1)
Other current liabilities	(15)	(10)
Other assets	12	(1)
Other liabilities	5
Net cash provided by operating activities	308	257
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(208)	(231)
Purchases of debt and equity securities	(6)	(6)
Proceeds from sales and maturities of debt and equity securities	4	3
Other	(11)	(4)
Net cash used in investing activities	(221)	(238)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt	(60)	(12)
Notes payable to affiliated companies	(31)
Other		(1)
Net cash provided by financing activities	(91)	(13)
Net increase (decrease) in cash and cash equivalents	(4)	6
Cash and cash equivalents at beginning of period	24	9
Cash and cash equivalents at end of period	20	15
Significant non-cash transactions:
Accrued capital expenditures	76	64
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	122	110
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	42	39
Deferred income taxes	23	(7)
Equity in (earnings) losses of unconsolidated affiliates	(2)	(2)
Accrued pension and other post-retirement benefit costs	(2)	(1)
Provision for rate refunds	7	23
(Increase) decrease in
Receivables	27	22
Receivable from affiliated companies	12
Inventory	45	37
Other current assets	22	79
Increase (decrease) in
Accounts payable	(44)	(15)
Accounts payable to affiliated companies	(4)	19
Taxes accrued	(49)	46
Other current liabilities	15	18
Other assets	(1)	4
Other liabilities	(5)	(1)
Net cash provided by operating activities	208	371
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(209)	(121)
Other	(2)
Net cash used in investing activities	(211)	(121)
CASH FLOWS FROM FINANCING ACTIVITIES
Notes payable to affiliated companies	3	(257)
Net cash provided by financing activities	3	(257)
Net increase (decrease) in cash and cash equivalents		(7)
Cash and cash equivalents at beginning of period		19
Cash and cash equivalents at end of period		12
Significant non-cash transactions:
Accrued capital expenditures	$ 92	$ 52

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]	Common Stock [Member]	Common Stock [Member]Common Stockholders' Equity [Member]	Common Stock [Member]Common Stock [Member]	Common Stock [Member]Additional Paid-in Capital [Member]	Preferred Stock [Member]	[4]	Preferred Stock [Member]Preferred Stock [Member]		Preferred Stock [Member]Common Stockholders' Equity [Member]	[4]
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	622			620				620								2					237		235				235								2
Net income (attributable to parent)	620																	323	323		235															177	103		103				(25)			(25)	100	110		110
Other comprehensive income (loss)	11			11						13		(3)		1				1		1	2		2						2								0
Stock issuances, shares																																																					1,000,000
Stock issuances																																																			$ 47	$ 47		$ 47
Common stock dividends	(625)			(625)				(625)										(250)	(250)
Distributions to noncontrolling interest in subsidiaries	(1)															(1)
Other	7	[1]		0	[1]			13	[1]			(13)	[1]			7	[1]				(1)	[2]	(1)	[2]	(1)	[2]	6	[2]			(6)	[2]					0	[3]	6	[3]	(6)	[3]
Ending Balance at Mar. 31, 2018	41,798			41,792		$ 1	38,839	3,021		3		(4)		(68)		6					13,703		13,704		9,142		4,591		(16)		(1)		(12)		(1)
Ending Balance, in shares at Mar. 31, 2018						701,000,000
Ending Balance (member's equity) at Mar. 31, 2018																		11,435	11,441	(6)																8,126	5,721		5,723		(2)						4,221
Ending Balance (parent) at Mar. 31, 2018																																											$ 3,138	762	2,670	(294)		$ 1,772	860	912
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	893			900				900								(7)					248		249				249								(1)
Net income (attributable to parent)	900																	293	293		249															203	96		96				$ 69			69	110	$ 122		122
Other comprehensive income (loss)	(12)			(12)						(16)		4									3		3						2				1				1				1
Stock issuances, shares																																																					1,000,000				40,000,000
Stock issuances																																																			$ 28	$ 28		$ 28	$ 974		$ 974	[4]	$ 974
Common stock dividends	(676)			(676)				(676)
Other	4	[5]		(1)	[5]			23	[5]	(6)	[5]	$ (1)	[5]	(17)	[5]	5	[5]	(1)		(1)							6	[6]	(4)	[6]	0	[6]	(2)	[6]
Ending Balance at Mar. 31, 2019	$ 45,045		$ 974	$ 45,030		$ 1	$ 40,823	$ 3,360		$ (36)				$ (92)		$ 15					$ 14,508		$ 14,506		$ 9,143		$ 5,386		$ (14)		$ (1)		$ (8)		$ 2
Ending Balance, in shares at Mar. 31, 2019	40,000,000
Ending Balance, in shares at Mar. 31, 2019	728,000,000					728,000,000															100																						90,000,000					100
Ending Balance (member's equity) at Mar. 31, 2019																		$ 11,975	$ 11,982	$ (7)																$ 8,644	$ 6,192		$ 6,193		$ (1)						$ 4,449
Ending Balance (parent) at Mar. 31, 2019	$ 45,030																				$ 14,506																						$ 3,514	$ 762	$ 2,776	$ (24)		$ 2,213	$ 1,160	$ 1,053
[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 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]	Duke Energy issued 40 million depositary shares of preferred stock in the first quarter of 2019.
[5]	Amounts in Retained Earnings and Accumulated Other Comprehensive (Loss) Income primarily represent impacts to accumulated other comprehensive income as a result of the adoption of Accounting Standards Update 2018-02: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.
[6]	Amounts in Retained Earnings and Accumulated Other Comprehensive (Loss) Income primarily represent impacts to accumulated other comprehensive income as a result of the adoption of Accounting Standards Update 2018-02: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.

Condensed Consolidated Statem_5

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

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 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. ORGANIZATION AND 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 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. 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. March 31, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 377 $ 45 $ 8 $ 442 $ 67 $ 36 Other 134 12 12 141 39 39 Other Noncurrent Assets Other 39 38 — 8 6 — Total cash, cash equivalents and restricted cash $ 550 $ 95 $ 20 $ 591 $ 112 $ 75 INVENTORY Provisions for inventory write-offs were not material at March 31, 2019 , and December 31, 2018 . The components of inventory are presented in the tables below. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,231 $ 738 $ 1,033 $ 720 $ 313 $ 79 $ 321 $ 2 Coal 572 228 218 127 91 13 113 — Natural gas, oil and other fuel 299 41 213 112 101 19 1 23 Total inventory $ 3,102 $ 1,007 $ 1,464 $ 959 $ 505 $ 111 $ 435 $ 25 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 March 31, 2019 , and an immaterial impact to the Duke Energy results of operations and cash flows for the three months ended March 31, 2019 . Duke Energy elected the modified retrospective method of adoption effective January 1, 2019. Under the modified retrospective method of adoption, prior year reported results are not restated. For adoption, Duke Energy 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. No new accounting standards that have been issued but not yet adopted are expected to have a material impact on the Duke Energy Registrants as of March 31, 2019 .

Business Segments

Business Segments	3 Months Ended
	Mar. 31, 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 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 portion of Duke Energy’s commercial renewables energy portfolio to be sold includes 49 percent of 37 operating wind, solar and battery storage assets and 33 percent of 11 operating solar assets across the U.S. The sale will result in pretax proceeds to Duke Energy of $415 million . Duke Energy will retain control of these assets, and, therefore, no gain or loss is expected to be recognized in the Condensed Consolidated Statements of Operations upon closing of the transaction. The sale is subject to customary closing conditions, including approvals from the FERC, the Public Utility Commission of Texas and the Committee on Foreign Investment in the U.S. The transaction is expected to close in the second half of 2019. 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 March 31, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 5,321 $ 732 $ 106 $ 6,159 $ 4 $ — $ 6,163 Intersegment revenues 8 24 — 32 17 (49 ) — Total revenues $ 5,329 $ 756 $ 106 $ 6,191 $ 21 $ (49 ) $ 6,163 Segment income (loss) $ 750 $ 226 $ 13 $ 989 $ (89 ) $ — $ 900 Add back noncontrolling interest component (7 ) Net income $ 893 Segment assets $ 130,406 $ 12,639 $ 4,378 $ 147,423 $ 3,536 $ 177 $ 151,136 Three Months Ended March 31, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 5,315 $ 702 $ 101 $ 6,118 $ 17 $ — $ 6,135 Intersegment revenues 8 25 — 33 18 (51 ) — Total revenues $ 5,323 $ 727 $ 101 $ 6,151 $ 35 $ (51 ) $ 6,135 Segment income (loss) (a)(b)(c) $ 750 $ 116 $ 20 $ 886 $ (266 ) $ — $ 620 Add back noncontrolling interest component 2 Net income $ 622 (a) Electric Utilities and Infrastructure includes regulatory and legislative impairment charges related to rate case orders, settlements or other actions of regulators or legislative bodies. See Note 3 for additional information. (b) Gas Utilities and Infrastructure includes an impairment of the investment in Constitution. See Note 3 for additional information. (c) Other includes the loss on the sale of Beckjord described below, costs to achieve the Piedmont acquisition 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 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 three months ended March 31, 2018. The sale included the transfer of coal ash basins and other real property and indemnification from any and all potential future claims related to the property, whether arising under environmental laws or otherwise. 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 March 31, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 355 $ 176 $ 531 $ — $ — $ 531 Segment income/Net (loss) income $ 36 $ 35 $ 71 $ (2 ) $ — $ 69 Segment assets $ 6,058 $ 3,051 $ 9,109 $ 37 $ (2 ) $ 9,144 Three Months Ended March 31, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 336 $ 174 $ 510 $ 14 $ 524 Segment income/Net loss (a) $ 33 $ 34 $ 67 $ (92 ) $ (25 ) (a) Other includes the loss on the sale of Beckjord described above.

Regulatory Matters

Regulatory Matters	3 Months Ended
	Mar. 31, 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). Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. Duke Energy Progress filed a similar request 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. 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 percent increase in annual base revenues. The 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 percent and a capital structure of 52 percent equity and 48 percent 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, 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 from the June 22, 2018, Order Accepting Stipulation, Deciding Contested Issues and Requiring Revenue Reduction. On August 8, 2018, the Public Staff filed a Notice of Cross 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 Public Staff contends the commission’s 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. On March 14, 2019, the North Carolina Attorney General’s Office filed a motion for extension of time to file its brief. On March 18, 2019, the North Carolina Supreme Court granted the North Carolina Attorney General’s motion, and the Appellant’s brief was filed on April 26, 2019. The Appellee response briefs are due on August 24, 2019. 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 10.0 percent increase in retail revenues. The rate increase is 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 percent. 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 provides that costs incurred after January 1, 2019, for the GIP 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’s hearing officer on March 13, 2019. An evidentiary hearing began on March 21, 2019, and concluded March 27, 2019. On May 1, 2019, the PSCSC issued a Commission Directive on Duke Energy Carolinas’ application for a retail rate increase. The Directive granted, among other things: a retail rate increase of $107 million , excluding the EDIT Rider; a return on equity of 9.5 percent ; and a capital structure of 53 percent equity and 47 percent debt. The Directive denied the recovery of coal ash costs of approximately $115 million . Based upon legal analysis and Duke Energy Carolinas' intention to file a Petition for Rehearing with the PSCSC, Duke Energy Carolinas has not recorded an adjustment for its deferred coal ash costs. The Directive also denied recovery of a return on pre-construction costs associated with the canceled Lee Nuclear Project. Duke Energy Carolinas is evaluating the financial statement impacts of this Directive and will record associated one-time costs when the final order is issued. Except for the coal ash matter, the financial statement impacts of this Directive are not material. An order and revised customer rates are expected by mid-2019. 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. Duke Energy Carolinas is working with wholesale customers that did not intervene in this case to implement the same settlement terms. 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 is subject to approval from FERC for the four FERC-licensed plants, as well as other state regulatory agencies and is 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 September 4, 2018, the Public Staff filed comments supporting the CPCN transfer with conditions. On September 18, 2018, Duke Energy Carolinas filed reply comments opposing the Public Staff’s proposed conditions. On November 29, 2018, the NCUC issued a procedural order and held an evidentiary hearing on this matter on February 5, 2019. On March 27, 2019, Duke Energy Carolinas and the Public Staff filed proposed orders with the NCUC. On August 28, 2018, Duke Energy Carolinas filed with PSCSC its 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. 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, given that compliance by the deadline set in the Order was not possible because the conveyance of the projects is contingent on the receipt of state regulatory approvals, which were not anticipated to be issued by February 25, 2019. On February 14, 2019, FERC issued an Order Granting Extensions of Time until August 26, 2019, to comply with the requirements of the Order. If commission approvals are not received, Duke Energy Carolinas can cancel the sales agreement and retain the hydro facilities. If commission approvals are received, the closing is expected to occur in 2019. After closing, 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 Carolinas cannot predict the outcome of this matter. 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 percent increase in annual base revenues. Subsequent to the filing, Duke Energy Progress adjusted the requested amount to $420 million , representing an approximate 13 percent increase. The 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 percent and a capital structure of 52 percent equity and 48 percent 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 February 23, 2018, Order Accepting Stipulation, Deciding Contested Issues and Granting Partial Rate Increase issued by the NCUC. The Public Staff contend the commission’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 Accepting Stipulation, Deciding Contested Issues and Granting Partial Rate Increase. 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. On November 29, 2018, the North Carolina Supreme Court adopted a schedule for briefing set forth in the motion to consolidate the Duke Energy Progress and Duke Energy Carolinas appeals. On March 14, 2019, the North Carolina Attorney General’s Office filed a motion for extension of time to file its brief. On March 18, 2019, the North Carolina Supreme Court granted the North Carolina Attorney General’s motion, and the Appellant’s brief was filed on April 26, 2019. The Appellee response briefs are due on August 24, 2019. Duke Energy Progress cannot predict the outcome of this matter. 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 percent increase in annual base revenues. The rate increase is 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 percent. 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 after January 1, 2019, for the GIP 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’s hearing officer on March 13, 2019. An evidentiary hearing began on April 11, 2019, and concluded on April 17, 2019. On May 8, 2019, the PSCSC issued a Commission Directive on Duke Energy Progress’ application for a retail rate increase. The Directive granted, among other things: a retail rate increase of $41 million , excluding the EDIT Rider; a return on equity of 9.5 percent and a capital structure of 53 percent equity and 47 percent debt. The Directive denied the recovery of coal ash costs of approximately $65 million . Based upon legal analysis and Duke Energy Progress' intention to file a Petition for Rehearing with the PSCSC, Duke Energy Progress has not recorded an adjustment for its deferred coal ash costs. Duke Energy Progress is evaluating the financial statement impacts of this Directive and will record associated one-time costs when the final order is issued. Except for the coal ash matter, the financial statement impacts of this Directive are not material. An order and revised customer rates are expected by mid-2019. 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 an existing natural gas pipeline to serve the natural gas plant. The lease 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 denying the CPCN for the contingent simple cycle unit without prejudice to Duke Energy Progress to refile for approval in the future. On March 28, 2018, 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 November 30, 2018, the NCUC issued an order scheduling hearings, requiring filing of testimony, establishing discovery guidelines and requiring public notice. On February 7, 2019, Duke Energy Progress made a joint filing with the Public Staff, which accepted the Public Staff’s proposed conditions and requested that the NCUC cancel the evidentiary hearing. On February 19, 2019, the NCUC granted the request to cancel the hearing. On March 22, 2019, Duke Energy Progress and the Public Staff filed a Joint Proposed Order now pending before the NCUC. Duke Energy Progress cannot predict the outcome of this matter. The carrying value of the 376 -MW Asheville coal-fired plant, including associated ash basin closure costs, of $302 million and $327 million is included in Generation facilities to be retired, net on Duke Energy Progress' Condensed Consolidated Balance Sheets as of March 31, 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. 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. Storm costs are currently expected to be fully recovered by approximately mid-2021. 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. The FPSC has scheduled the hearing to begin on May 21, 2019, to consider the Storm Cost Settlement Agreement filed with the FPSC. If approved, the Storm Cost Settlement Agreement would obligate Duke Energy Florida to capitalize $18 million of storm costs and remove $6 million of operating and maintenance expense, thereby reducing the requested storm cost recovery amount by $24 million . Duke Energy Florida will also implement process changes with respect to storm cost restoration. At March 31, 2019, and December 31, 2018, Duke Energy Florida's Condensed Consolidated Balance Sheets included approximately $157 million and $217 million , respectively, of recoverable costs under the FPSC's storm rule in Regulatory assets within Current Assets and Other Noncurrent Assets related to storm recovery for Hurricane Irma and Hurricane Nate. Duke Energy Florida cannot predict the outcome of this matter. In October 2018, Duke Energy Florida’s service territory suffered damage when Hurricane Michael made landfall as a strong Category 5 hurricane with maximum sustained winds of 160 mph. The storm caused catastrophic damage from wind and storm surge, particularly from Panama City Beach to Mexico Beach, resulting in widespread outages and significant damage to transmission and distribution facilities across the central Florida Panhandle. In response to Hurricane Michael, Duke Energy Florida restored service to approximately 72,000 customers. Total current estimated incremental operation and maintenance and capital costs are $360 million . Approximately $70 million and $35 million of the costs are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets as of March 31, 2019, and December 31, 2018, respectively. Approximately $213 million and $165 million of costs represent recoverable costs under the FPSC’s storm rule and Duke Energy Florida's Open Access Transmission Tariff formula rates and are included in Regulatory assets within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets as of March 31, 2019, and December 31, 2018, respectively. Additional costs could be incurred in 2019 related to this fourth quarter 2018 storm. Duke Energy Florida filed a petition with the FPSC on April 30, 2019, to recover incremental storm restoration costs for Hurricane Michael. The estimated recovery amount is approximately $221 million to be recovered over a 12 -month period beginning in July 2019, subject to true up through the Storm Surcharge consistent with the provisions of the 2017 Settlement. Concurrently, Duke Energy Florida filed for approval a stipulation that would apply tax savings resulting from the Tax Act toward storm costs in lieu of implementing a storm surcharge. Storm costs are currently expected to be fully recovered by approximately year-end 2021. Duke Energy Florida cannot predict the outcome of this matter. Tax Act Pursuant to Duke Energy Florida's 2017 Settlement, on May 31, 2018, Duke Energy Florida filed a petition related to the Tax Act, which included revenue requirement impacts of annual tax savings of $134 million and estimated annual amortization of EDIT of $67 million for a total of $201 million . Of this amount, $50 million would be offset by accelerated depreciation of Crystal River 4 and 5 coal units and an estimated $151 million would be offset by Hurricane Irma storm cost recovery as explained in the Storm Restoration Cost Recovery section above. On December 27, 2018, Duke Energy Florida filed actual EDIT balances and amortization based on its 2017 filed tax return. This increased the revenue requirement impact of the amortization of EDIT by $4 million , from $67 million to $71 million , which increased the total storm amortization from $151 million to $155 million . On January 8, 2019, the FPSC approved a joint motion by Duke Energy Florida and the Office of Public Counsel resolving all stipulated positions. As part of that stipulation, Duke Energy Florida agreed to seek a Private Letter Ruling (PLR) from the IRS on its treatment of cost of removal (COR) as mostly protected by tax normalization rules. If the IRS rules that COR is not protected by tax normalization rules, then Duke Energy Florida will make a final adjustment to the amortization of EDIT and an adjustment to the storm recovery amount retroactive to January 2018. The IRS has communicated that it will not issue individual PLRs on the treatment of COR. Rather, the IRS is drafting a notice that will request comments on a number of issues, including COR, and the IRS plans to issue industrywide guidance on those issues. Duke Energy Florida cannot predict the outcome of this matter. Solar Base Rate Adjustment On July 31, 2018, Duke Energy Florida petitioned the FPSC to include in base rates the revenue requirements for its first two solar generation projects, the Hamilton Project and the Columbia Project, as authorized by the 2017 Settlement. The Hamilton Project, which was placed into service on December 22, 2018, has an annual retail revenue requirement of $15 million and the increase was effective in January 2019. The Columbia Project has a projected annual revenue requirement of $14 million and a projected in-service date in early 2020; the associated rate increase would take place with the first month’s billing cycle after the Columbia Project goes into service. At its October 30, 2018, Agenda Conference, the FPSC approved the rate increase related to the Hamilton Project to go into effect beginning with the first billing cycle in January 2019 under its file and suspend authority. On April 2, 2019, the commission approved both solar projects as filed. On March 25, 2019, Duke Energy Florida petitioned the FPSC to include in base rates the revenue requirements for its next wave of solar generation projects, the Trenton, Lake Placid and DeBary Solar Projects, as authorized by the 2017 Settlement. The annual retail revenue requirement for the Trenton and Lake Placid Projects is $13 million and $8 million , respectively, with projected in-service dates in the fourth quarter of 2019. The DeBary Project has a projected annual revenue requirement of $11 million and a projected in-service date in the first quarter of 2020. The associated rate increase would take place with the first month’s billing cycle after each solar generation project goes into service. Duke Energy Florida cannot predict the outcome of this matter. Duke Energy Ohio Tax Act – Ohio On July 25, 2018, Duke Energy Ohio filed an application to establish a new rider to implement the benefits of the Tax Act for electric distribution customers. The new rider will flow through to customers the benefit of the lower statutory federal tax rate from 35 to 21 percent since January 1, 2018, all future benefits of the lower tax rates and a full refund of deferred income taxes collected at the higher tax rates in prior years. Deferred income taxes subject to normalization rules will be refunded consistent with federal law and deferred income taxes not subject to normalization rules will be refunded over a 10-year period. Duke Energy Ohio's transmission rates reflect lower federal income tax but guidance fro

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 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 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 of the 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. Three Months Ended March 31, 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 (2 ) 2 2 1 2 (6 ) — — Cash reductions (8 ) — — — — (8 ) — — Balance at end of period $ 67 $ 13 $ 13 $ 5 $ 8 $ 34 $ 5 $ 2 Three Months Ended March 31, 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 4 1 3 1 1 — 1 — Cash reductions (5 ) — (2 ) (1 ) (1 ) (3 ) — — Balance at end of period $ 80 $ 11 $ 16 $ 3 $ 12 $ 44 $ 6 $ 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 $ 45 Duke Energy Carolinas 12 Duke Energy Ohio 22 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 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 determination that all ash basins must be excavated. 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 January 23, 2019, the court granted the parties’ joint motion for a four-month stay of the proceedings, until June 3, 2019, to allow the parties to discuss potential resolution. If the case is not fully resolved at that time, litigation will resume. The trial remains scheduled for August 2020. 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. In light of the NCDEQ's determination that all ash basins must be excavated, on April 29, 2019, the court decided to stay any activity in the case until August 2019, at which time the court will hold another status conference. 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 determination that all ash basins must be excavated. On April 19, 2019, the court entered an order staying the case through August 7, 2019, at which time the court will hold a status conference. 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 determination that all ash basins must be excavated. On April 19, 2019, the court entered an order staying the case through August 7, 2019, at which time the court will hold a status conference. 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 March 31, 2019 , there were 139 asserted claims for non-malignant cases with cumulative relief sought of up to $34 million , and 57 asserted claims for malignant cases with cumulative relief sought of up to $18 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 $617 million at March 31, 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 $764 million in excess of the self-insured retention. Receivables for insurance recoveries were $739 million at March 31, 2019 , and 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 October 16, 2014, Duke Energy Progress and Duke Energy Florida sued the U.S. in the U.S. Court of Federal Claims. 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. On June 22, 2018, Duke Energy Progress and Duke Energy Florida filed a complaint for damages incurred for 2014 through first quarter 2018. 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 seeks civil, statutory and contractual remedies related to Duke Energy Florida’s $67 million draw in early 2019, on Fluor’s letter of credit and offset of invoiced amounts. Duke Energy Florida moved to dismiss all counts of Fluor's amended complaint, and on April 16, 2019, the court dismissed Fluor's complaint without prejudice. On April 26, 2019, Fluor filed a second amended complaint. Duke Energy Florida is attempting to recover from Fluor $110 million in additional costs incurred by Duke Energy Florida. Duke Energy Florida cannot predict the outcome of this matter. 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) March 31, 2019 December 31, 2018 Reserves for Legal Matters Duke Energy $ 66 $ 65 Duke Energy Carolinas 8 9 Progress Energy 57 54 Duke Energy Progress 15 12 Duke Energy Florida 24 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	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	LEASES As described in Note 1, Duke Energy adopted the revised accounting guidance for Leases effective January 1, 2019, using the modified retrospective method of adoption, which does not require restatement of prior year reported results. Adoption of the new standard resulted in the recording of ROU assets and operating lease liabilities as follows: As of January 1, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont ROU assets $ 1,750 $ 153 $ 863 $ 407 $ 456 $ 23 $ 61 $ 26 Operating lease liabilities – current 205 28 96 35 61 1 4 4 Operating lease liabilities – noncurrent 1,504 127 766 371 395 22 58 25 As part of its operations, Duke Energy leases certain aircraft, space on communication towers, industrial equipment, fleet vehicles, fuel transportation (barges and railcars), land and office space under various terms and expiration dates. Additionally, Duke Energy Carolinas, Duke Energy Progress and Duke Energy Indiana have finance leases related to firm natural gas pipeline transportation capacity. Duke Energy Progress and Duke Energy Florida have entered into certain PPAs, which are classified as finance and operating leases. Duke Energy has certain lease agreements, which include variable lease payments that are based on the usage of an asset. These variable lease payments are not included in the measurement of the ROU assets or operating lease liabilities on the 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 in 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 $64 million for the three months ended March 31, 2019 . As of March 31, 2019 , renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,345 million and accumulated depreciation of $631 million . These assets are principally classified as nonregulated electric generation and transmission assets. The following table presents the components of lease expense. Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Operating lease expense (a) $ 72 $ 12 $ 42 $ 19 $ 23 $ 3 $ 5 $ 1 Short-term lease expense (a) 7 2 3 1 2 — 1 — Variable lease expense (a) 11 8 2 1 1 — — — Finance lease expense Amortization of leased assets (b) 27 1 3 1 2 — — — Interest on lease liabilities (c) 17 4 6 4 2 — — — Total finance lease expense 44 5 9 5 4 — — — Total lease expense $ 134 $ 27 $ 56 $ 26 $ 30 $ 3 $ 6 $ 1 (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 March 31, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 271 $ 32 $ 125 $ 47 $ 78 $ 2 $ 6 $ 5 2021 238 29 112 46 66 2 5 5 2022 192 19 90 35 55 2 4 5 2023 180 19 89 34 55 2 4 5 2024 169 16 89 35 54 2 4 5 Thereafter 1,057 66 530 309 221 22 67 9 Total operating lease payments 2,107 181 1,035 506 529 32 90 34 Less: present value discount (436 ) (32 ) (198 ) (118 ) (80 ) (10 ) (29 ) (4 ) Total operating lease liabilities (a) $ 1,671 $ 149 $ 837 $ 388 $ 449 $ 22 $ 61 $ 30 (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 non-cancelable 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 March 31, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2020 $ 185 $ 19 $ 69 $ 44 $ 25 $ 1 $ 1 2021 191 18 69 44 25 — 1 2022 194 14 69 44 25 — 1 2023 179 14 69 44 25 — 1 2024 180 14 69 44 25 — 1 Thereafter 889 195 573 558 15 — 28 Total finance lease payments 1,818 274 918 778 140 1 33 Less: amount representing interest (729 ) (166 ) (495 ) (467 ) (28 ) — (23 ) Total finance lease liabilities $ 1,089 $ 108 $ 423 $ 311 $ 112 $ 1 $ 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. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Classification Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Assets Operating Operating Lease ROU Assets, net $ 1,698 $ 146 $ 835 $ 388 $ 447 $ 22 $ 61 $ 27 Finance Net property, plant and equipment 1,081 122 428 310 118 — 10 — Total lease assets $ 2,779 $ 268 $ 1,263 $ 698 $ 565 $ 22 $ 71 $ 27 Liabilities Current Operating Other current liabilities $ 183 $ 26 $ 89 $ 27 $ 62 $ 1 $ 4 $ 4 Finance Current maturities of long-term debt 121 6 23 6 17 1 — — Noncurrent Operating Operating Lease Liabilities 1,488 123 748 361 387 21 57 26 Finance Long-Term Debt 968 102 400 305 95 — 10 — Total lease liabilities $ 2,760 $ 257 $ 1,260 $ 699 $ 561 $ 23 $ 71 $ 30 Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Cash paid for amounts included in the measurement of lease liabilities (a) Operating cash flows from operating leases $ 67 $ 6 $ 31 $ 14 $ 17 $ 1 $ 2 $ 2 Operating cash flows from finance leases 17 4 6 4 2 — — — Financing cash flows from finance leases 27 1 3 1 2 — — — Lease assets obtained in exchange for new lease liabilities (non-cash) Finance $ 175 $ — $ 175 $ 175 $ — $ — $ — $ — Operating (b) 7 — — — — — — — (a) No amounts were classified as investing cash flows from operating leases for the three months ended March 31, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Weighted-average remaining lease term (years) Operating leases 11 9 11 13 9 18 19 7 Finance leases 13 19 16 18 11 — 27 — Weighted-average discount rate (a) Operating leases 3.9 % 3.7 % 3.8 % 3.9 % 3.7 % 4.2 % 4.1 % 3.6 % Finance leases 6.9 % 12.9 % 11.4 % 12.5 % 8.3 % 3.3 % 11.7 % — % (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 in 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 $64 million for the three months ended March 31, 2019 . As of March 31, 2019 , renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,345 million and accumulated depreciation of $631 million . These assets are principally classified as nonregulated electric generation and transmission assets. The following table presents the components of lease expense. Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Operating lease expense (a) $ 72 $ 12 $ 42 $ 19 $ 23 $ 3 $ 5 $ 1 Short-term lease expense (a) 7 2 3 1 2 — 1 — Variable lease expense (a) 11 8 2 1 1 — — — Finance lease expense Amortization of leased assets (b) 27 1 3 1 2 — — — Interest on lease liabilities (c) 17 4 6 4 2 — — — Total finance lease expense 44 5 9 5 4 — — — Total lease expense $ 134 $ 27 $ 56 $ 26 $ 30 $ 3 $ 6 $ 1 (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 March 31, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 271 $ 32 $ 125 $ 47 $ 78 $ 2 $ 6 $ 5 2021 238 29 112 46 66 2 5 5 2022 192 19 90 35 55 2 4 5 2023 180 19 89 34 55 2 4 5 2024 169 16 89 35 54 2 4 5 Thereafter 1,057 66 530 309 221 22 67 9 Total operating lease payments 2,107 181 1,035 506 529 32 90 34 Less: present value discount (436 ) (32 ) (198 ) (118 ) (80 ) (10 ) (29 ) (4 ) Total operating lease liabilities (a) $ 1,671 $ 149 $ 837 $ 388 $ 449 $ 22 $ 61 $ 30 (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 non-cancelable 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 March 31, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2020 $ 185 $ 19 $ 69 $ 44 $ 25 $ 1 $ 1 2021 191 18 69 44 25 — 1 2022 194 14 69 44 25 — 1 2023 179 14 69 44 25 — 1 2024 180 14 69 44 25 — 1 Thereafter 889 195 573 558 15 — 28 Total finance lease payments 1,818 274 918 778 140 1 33 Less: amount representing interest (729 ) (166 ) (495 ) (467 ) (28 ) — (23 ) Total finance lease liabilities $ 1,089 $ 108 $ 423 $ 311 $ 112 $ 1 $ 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. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Classification Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Assets Operating Operating Lease ROU Assets, net $ 1,698 $ 146 $ 835 $ 388 $ 447 $ 22 $ 61 $ 27 Finance Net property, plant and equipment 1,081 122 428 310 118 — 10 — Total lease assets $ 2,779 $ 268 $ 1,263 $ 698 $ 565 $ 22 $ 71 $ 27 Liabilities Current Operating Other current liabilities $ 183 $ 26 $ 89 $ 27 $ 62 $ 1 $ 4 $ 4 Finance Current maturities of long-term debt 121 6 23 6 17 1 — — Noncurrent Operating Operating Lease Liabilities 1,488 123 748 361 387 21 57 26 Finance Long-Term Debt 968 102 400 305 95 — 10 — Total lease liabilities $ 2,760 $ 257 $ 1,260 $ 699 $ 561 $ 23 $ 71 $ 30 Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Cash paid for amounts included in the measurement of lease liabilities (a) Operating cash flows from operating leases $ 67 $ 6 $ 31 $ 14 $ 17 $ 1 $ 2 $ 2 Operating cash flows from finance leases 17 4 6 4 2 — — — Financing cash flows from finance leases 27 1 3 1 2 — — — Lease assets obtained in exchange for new lease liabilities (non-cash) Finance $ 175 $ — $ 175 $ 175 $ — $ — $ — $ — Operating (b) 7 — — — — — — — (a) No amounts were classified as investing cash flows from operating leases for the three months ended March 31, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Weighted-average remaining lease term (years) Operating leases 11 9 11 13 9 18 19 7 Finance leases 13 19 16 18 11 — 27 — Weighted-average discount rate (a) Operating leases 3.9 % 3.7 % 3.8 % 3.9 % 3.7 % 4.2 % 4.1 % 3.6 % Finance leases 6.9 % 12.9 % 11.4 % 12.5 % 8.3 % 3.3 % 11.7 % — % (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	3 Months Ended
	Mar. 31, 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). Three Months Ended March 31, 2019 Duke Duke Duke Maturity Interest Duke Energy Energy Energy Issuance Date Date Rate Energy (Parent) Progress Ohio Unsecured Debt March 2019 (a) March 2022 3.251 % (b) $ 300 $ 300 $ — $ — March 2019 (a) March 2022 3.227 % 300 300 — — 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 — Total issuances $ 2,000 $ 600 $ 600 $ 800 (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. 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 March 31, 2019 Unsecured Debt Duke Energy (Parent) September 2019 5.050 % $ 500 Piedmont September 2019 3.181 % (b) 350 Duke Energy Kentucky October 2019 4.650 % 100 Progress Energy December 2019 4.875 % 350 First Mortgage Bonds Duke Energy Ohio April 2019 5.450 % 450 Duke Energy Florida January 2020 1.850 % 250 Other (a) 501 Current maturities of long-term debt $ 2,501 (a) Includes finance lease obligations, amortizing debt and small bullet maturities. (b) Amount drawn under the Piedmont senior unsecured term loan facility has a floating interest rate. 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. March 31, 2019 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Facility size (a) $ 8,000 $ 2,650 $ 1,750 $ 1,400 $ 650 $ 450 $ 600 $ 500 Reduction to backstop issuances Commercial paper (b) (2,657 ) (884 ) (859 ) (150 ) (299 ) (62 ) (252 ) (151 ) Outstanding letters of credit (53 ) (45 ) (4 ) (2 ) — — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity under the Master Credit Facility $ 4,709 $ 1,721 $ 637 $ 998 $ 351 $ 388 $ 267 $ 347 (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 March 31, 2019 (in millions) Facility size Amount Drawn Duke Energy (Parent) Three-Year Revolving Credit Facility $ 1,000 $ 500 Duke Energy Progress Term Loan Facility (a) 700 700 Piedmont Term Loan Facility 350 350 (a) $650 million was drawn under the term loan in January and February 2019.

Asset Retirement Obligations

Asset Retirement Obligations	3 Months Ended
	Mar. 31, 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. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Decommissioning of nuclear power facilities (a) $ 5,753 $ 2,368 $ 3,239 $ 2,709 $ 530 $ — $ — $ — Closure of ash impoundments 6,961 3,013 3,197 3,177 20 52 699 — Other 321 47 70 37 33 41 20 19 Total ARO $ 13,035 $ 5,428 $ 6,506 $ 5,923 $ 583 $ 93 $ 719 $ 19 Less: current portion 779 209 456 452 4 6 108 — Total noncurrent ARO $ 12,256 $ 5,219 $ 6,050 $ 5,471 $ 579 $ 87 $ 611 $ 19 (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) 110 48 57 50 7 1 7 — Liabilities settled (c) (184 ) (76 ) (97 ) (82 ) (15 ) (1 ) (10 ) — Revisions in estimates of cash flows (d) 2,642 1,507 1,135 1,135 — — — — Balance at March 31, 2019 $ 13,035 $ 5,428 $ 6,506 $ 5,923 $ 583 $ 93 $ 719 $ 19 (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 three months ended March 31, 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) Relates to increases in closure estimates for certain ash impoundments as a result of the NCDEQ's determination that all ash basins must be excavated. 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) March 31, 2019 December 31, 2018 Duke Energy $ 6,102 $ 5,579 Duke Energy Carolinas 3,443 3,133 Duke Energy Progress 2,659 2,446

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 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 March 31, 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 March 31, 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.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 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 March 31, (in millions) 2019 2018 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 212 $ 220 Indemnification coverages (b) 5 6 JDA revenue (c) 23 34 JDA expense (c) 93 54 Intercompany natural gas purchases (d) 4 4 Progress Energy Corporate governance and shared service expenses (a) $ 176 $ 191 Indemnification coverages (b) 9 8 JDA revenue (c) 93 54 JDA expense (c) 23 34 Intercompany natural gas purchases (d) 19 19 Duke Energy Progress Corporate governance and shared service expenses (a) $ 106 $ 118 Indemnification coverages (b) 4 3 JDA revenue (c) 93 54 JDA expense (c) 23 34 Intercompany natural gas purchases (d) 19 19 Duke Energy Florida Corporate governance and shared service expenses (a) $ 70 $ 73 Indemnification coverages (b) 5 5 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 89 Indemnification coverages (b) 1 1 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 97 $ 101 Indemnification coverages (b) 2 2 Piedmont Corporate governance and shared service expenses (a) $ 32 $ 36 Indemnification coverages (b) 1 1 Intercompany natural gas sales (d) 23 23 Natural gas storage and transportation costs (e) 5 6 (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 March 31, 2019 Intercompany income tax receivable $ 1 $ 65 $ — $ 22 $ 6 $ — $ — Intercompany income tax payable — — 11 — — 7 7 December 31, 2018 Intercompany income tax receivable $ 52 $ 47 $ 29 $ — $ — $ 8 $ — Intercompany income tax payable — — — 16 3 — 45

Derivatives and Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING The Duke Energy Registrants use commodity and interest rate contracts to manage commodity price risk and interest rate risk. The primary use of commodity derivatives is to hedge the generation portfolio against changes in the prices of electricity and natural gas. Piedmont enters into natural gas supply contracts to provide diversification, reliability and natural gas cost benefits to its customers. Interest rate derivatives are used to manage interest rate risk associated with borrowings. All derivative instruments not identified as NPNS are recorded at fair value as assets or liabilities on the 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 months ended March 31, 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. March 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 923 $ — $ — $ — $ — $ — Undesignated contracts 1,321 300 800 250 550 27 Total notional amount (a) $ 2,244 $ 300 $ 800 $ 250 $ 550 $ 27 December 31, 2018 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 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 $422 million in cash flow hedges and $194 million in undesignated contracts as of March 31, 2019 , and 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. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 6,196 — — — — 829 5,367 — Natural gas (millions of dekatherms) 742 128 174 174 — — 1 439 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 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 March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 16 $ 3 $ 5 $ 5 $ — $ 1 $ 5 $ 2 Noncurrent 6 2 3 3 — — — — Total Derivative Assets – Commodity Contracts $ 22 $ 5 $ 8 $ 8 $ — $ 1 $ 5 $ 2 Interest Rate Contracts Designated as Hedging Instruments Current $ 1 $ — $ — $ — $ — $ — $ — $ — Noncurrent 2 — — — — — — — Not Designated as Hedging Instruments Current 1 — — — — — — — Noncurrent 9 — — — — — — — Total Derivative Assets – Interest Rate Contracts $ 13 $ — $ — $ — $ — $ — $ — $ — Total Derivative Assets $ 35 $ 5 $ 8 $ 8 $ — $ 1 $ 5 $ 2 Derivative Liabilities March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 21 $ 12 $ 3 $ 3 $ — $ — $ — $ 6 Noncurrent 140 5 19 4 — — — 115 Total Derivative Liabilities – Commodity Contracts $ 161 $ 17 $ 22 $ 7 $ — $ — $ — $ 121 Interest Rate Contracts Designated as Hedging Instruments Current $ 25 $ — $ — $ — $ — $ — $ — $ — Noncurrent 9 — — — — — — — Not Designated as Hedging Instruments Current 42 22 19 3 17 1 — — Noncurrent 7 — 3 2 1 4 — — Total Derivative Liabilities – Interest Rate Contracts $ 83 $ 22 $ 22 $ 5 $ 18 $ 5 $ — $ — Total Derivative Liabilities $ 244 $ 39 $ 44 $ 12 $ 18 $ 5 $ — $ 121 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 March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 18 $ 3 $ 5 $ 5 $ — $ 1 $ 5 $ 2 Gross amounts offset (4 ) (2 ) (1 ) (1 ) — — — — Net amounts presented in Current Assets: Other $ 14 $ 1 $ 4 $ 4 $ — $ 1 $ 5 $ 2 Noncurrent Gross amounts recognized $ 17 $ 2 $ 3 $ 3 $ — $ — $ — $ — Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 14 $ 1 $ 1 $ 1 $ — $ — $ — $ — Derivative Liabilities March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 88 $ 34 $ 22 $ 6 $ 17 $ 1 $ — $ 6 Gross amounts offset (4 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Liabilities: Other $ 84 $ 32 $ 20 $ 4 $ 17 $ 1 $ — $ 6 Noncurrent Gross amounts recognized $ 156 $ 5 $ 22 $ 6 $ 1 $ 4 $ — $ 115 Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 153 $ 4 $ 20 $ 4 $ 1 $ 4 $ — $ 115 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. March 31, 2019 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 25 $ 14 $ 11 $ 11 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 25 14 11 11 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	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Investments In Debt And Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES Duke Energy’s investments in debt and equity securities are primarily comprised of investments held in (i) the NDTF at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) the grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to OPEB plans and (iii) Bison. The Duke Energy Registrants classify investments in debt securities as AFS and investments in equity securities as FV-NI. For investments in debt securities classified as AFS, the unrealized gains and losses are included in other comprehensive income until realized, at which time, they are reported 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 March 31, 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. March 31, 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 2,923 65 5,061 2,402 95 4,475 Corporate debt securities 17 2 624 4 13 566 Municipal bonds 5 1 317 1 4 353 U.S. government bonds 25 5 1,102 14 12 1,076 Other debt securities 1 1 145 — 2 148 Total NDTF Investments $ 2,971 $ 74 $ 7,363 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 51 $ — $ — $ 22 Equity securities 47 — 112 36 1 99 Corporate debt securities 1 — 57 — 2 60 Municipal bonds 2 1 89 — 1 85 U.S. government bonds 1 — 52 1 — 45 Other debt securities — 1 61 — 1 58 Total Other Investments $ 51 $ 2 $ 422 $ 37 $ 5 $ 369 Total Investments $ 3,022 $ 76 $ 7,785 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 35 $ 19 Realized losses 30 13 AFS: Realized gains 10 5 Realized losses 11 13 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. March 31, 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 $ — $ — $ 57 $ — $ — $ 29 Equity securities 1,593 37 2,791 1,309 54 2,484 Corporate debt securities 9 2 354 2 9 341 Municipal bonds 1 — 62 — 1 81 U.S. government bonds 11 3 509 5 8 475 Other debt securities 1 1 140 — 2 143 Total NDTF Investments $ 1,615 $ 43 $ 3,913 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 23 $ 10 Realized losses 21 5 AFS: Realized gains 9 5 Realized losses 10 10 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. March 31, 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 $ — $ — $ 57 $ — $ — $ 59 Equity securities 1,330 28 2,270 1,093 41 1,991 Corporate debt securities 8 — 270 2 4 225 Municipal bonds 4 1 255 1 3 272 U.S. government bonds 14 2 593 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,356 $ 31 $ 3,450 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 47 $ — $ — $ 17 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 96 $ — $ — $ 64 Total Investments $ 1,358 $ 31 $ 3,546 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 12 $ 9 Realized losses 9 8 AFS: Realized gains 1 — Realized losses 1 3 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. March 31, 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 $ — $ — $ 43 $ — $ — $ 46 Equity securities 1,022 20 1,812 833 30 1,588 Corporate debt securities 6 — 204 2 3 171 Municipal bonds 4 1 254 1 3 271 U.S. government bonds 10 1 422 6 3 415 Other debt securities — — 3 — — 3 Total NDTF Investments $ 1,042 $ 22 $ 2,738 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 3 $ — $ — $ 6 Total Other Investments $ — $ — $ 3 $ — $ — $ 6 Total Investments $ 1,042 $ 22 $ 2,741 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 10 $ 8 Realized losses 8 8 AFS: Realized gains 1 — Realized losses 1 2 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. March 31, 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 $ — $ — $ 14 $ — $ — $ 13 Equity securities 308 8 458 260 11 403 Corporate debt securities 2 — 66 — 1 54 Municipal bonds — — 1 — — 1 U.S. government bonds 4 1 171 3 1 186 Other debt securities — — 2 — — 2 Total NDTF Investments (a) $ 314 $ 9 $ 712 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 50 $ — $ — $ 48 Total Investments $ 316 $ 9 $ 762 $ 263 $ 13 $ 707 (a) During the three months ended March 31, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant. Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 2 $ 1 Realized losses 1 — AFS: Realized losses — 1 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. March 31, 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 $ — $ 76 $ 29 $ — $ 67 Corporate debt securities — — 7 — — 8 Municipal bonds — 1 34 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 37 $ 1 $ 118 $ 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 months ended March 31, 2019 , and 2018, were insignificant. DEBT SECURITY MATURITIES The table below summarizes the maturity date for debt securities. March 31, 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 $ 74 $ 9 $ 41 $ 21 $ 20 $ 4 Due after one through five years 537 153 341 251 90 17 Due after five through 10 years 577 287 245 196 49 4 Due after 10 years 1,259 616 545 415 130 17 Total $ 2,447 $ 1,065 $ 1,172 $ 883 $ 289 $ 42

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is the exchange price to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. The fair value definition focuses on an exit price versus the acquisition cost. Fair value measurements use market data or assumptions market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs may be readily observable, corroborated by market data or generally unobservable. Valuation techniques maximize the use of observable inputs and minimize use of unobservable inputs. A midmarket pricing convention (the midpoint price between bid and ask prices) is permitted for use as a practical expedient. Fair value measurements are classified in three levels based on the fair value hierarchy as defined by GAAP. Certain investments are not categorized within the fair value hierarchy. These investments are measured at fair value using the NAV per share practical expedient. The 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 three months ended March 31, 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. March 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 5,061 $ 4,998 $ — $ — $ 63 NDTF debt securities 2,302 630 1,672 — — Other equity securities 112 112 — — — Other debt securities 310 103 207 — — Derivative assets 35 2 27 6 — Total assets 7,820 5,845 1,906 6 63 Derivative liabilities (244 ) (23 ) (100 ) (121 ) — Net assets (liabilities) $ 7,576 $ 5,822 $ 1,806 $ (115 ) $ 63 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 March 31, (in millions) 2019 2018 Balance at beginning of period $ (113 ) $ (114 ) Purchases, sales, issuances and settlements: Settlements (12 ) (14 ) Total gains included on the Condensed Consolidated Balance Sheet 10 4 Balance at end of period $ (115 ) $ (124 ) 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. March 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 2,791 $ 2,728 $ — $ 63 NDTF debt securities 1,122 212 910 — Derivative assets 5 — 5 — Total assets 3,918 2,940 915 63 Derivative liabilities (39 ) — (39 ) — Net assets $ 3,879 $ 2,940 $ 876 $ 63 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,270 $ 2,270 $ — $ 1,991 $ 1,991 $ — NDTF debt securities 1,180 418 762 1,162 427 735 Other debt securities 96 47 49 64 17 47 Derivative assets 8 — 8 4 — 4 Total assets 3,554 2,735 819 3,221 2,435 786 Derivative liabilities (44 ) — (44 ) (44 ) — (44 ) Net assets $ 3,510 $ 2,735 $ 775 $ 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,812 $ 1,812 $ — $ 1,588 $ 1,588 $ — NDTF debt securities 926 298 628 906 294 612 Other debt securities 3 3 — 6 6 — Derivative assets 8 — 8 4 — 4 Total assets 2,749 2,113 636 2,504 1,888 616 Derivative liabilities (12 ) — (12 ) (27 ) — (27 ) Net assets $ 2,737 $ 2,113 $ 624 $ 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 458 $ 458 $ — $ 403 $ 403 $ — NDTF debt securities 254 120 134 256 133 123 Other debt securities 50 1 49 48 1 47 Total assets 762 579 183 707 537 170 Derivative liabilities (18 ) — (18 ) (9 ) — (9 ) Net assets $ 744 $ 579 $ 165 $ 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 for the three months ended March 31, 2019 , and 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Other equity securities $ 76 $ 76 $ — $ — $ 67 $ 67 $ — $ — Other debt securities 42 — 42 — 41 — 41 — Derivative assets 5 — — 5 23 1 — 22 Total assets $ 123 $ 76 $ 42 $ 5 $ 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 March 31, (in millions) 2019 2018 Balance at beginning of period $ 22 $ 27 Purchases, sales, issuances and settlements: Settlements (10 ) (14 ) Total losses included on the Condensed Consolidated Balance Sheet (7 ) (6 ) Balance at end of period $ 5 $ 7 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. March 31, 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 (121 ) — (121 ) (141 ) — (141 ) Net (liabilities) assets $ (119 ) $ 2 $ (121 ) $ (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 March 31, (in millions) 2019 2018 Balance at beginning of period $ (141 ) $ (142 ) Total gains and settlements 20 10 Balance at end of period $ (121 ) $ (132 ) QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. March 31, 2019 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 1 RTO auction pricing FTR price – per MWh $ 0.17 - $ 2.40 Duke Energy Indiana FTRs 5 RTO auction pricing FTR price – per MWh (0.42 ) - 7.85 Piedmont Natural gas contracts (121 ) Discounted cash flow Forward natural gas curves – price per MMBtu 2.03 - 3.15 Duke Energy Total Level 3 derivatives $ (115 ) 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. March 31, 2019 December 31, 2018 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy (a) $ 56,182 $ 58,242 $ 54,529 $ 54,534 Duke Energy Carolinas 10,965 11,951 10,939 11,471 Progress Energy 19,251 20,942 18,911 19,885 Duke Energy Progress 9,048 9,469 8,204 8,300 Duke Energy Florida 7,265 8,000 7,321 7,742 Duke Energy Ohio 2,960 3,149 2,165 2,239 Duke Energy Indiana 3,722 4,242 3,782 4,158 Piedmont 2,138 2,243 2,138 2,180 (a) Book value of long-term debt includes $1.5 billion as of March 31, 2019 , and $1.6 billion as of December 31, 2018 , of unamortized debt discount and premium, net in purchase accounting adjustments related to the mergers with Progress Energy and Piedmont that are excluded from fair value of long-term debt. At both March 31, 2019 , and December 31, 2018 , fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and nonrecourse notes payable of VIEs are not materially different from their carrying amounts because of the short-term nature of these instruments and/or because the stated rates approximate market rates.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 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 three months ended March 31, 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 percent cash and 25 percent 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 March 31, 2019 350 475 325 250 Amounts borrowed at December 31, 2018 325 450 300 225 Restricted Receivables at March 31, 2019 534 630 495 317 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) March 31, 2019 December 31, 2018 Receivables of VIEs $ 5 $ 5 Regulatory Assets: Current 52 52 Current Assets: Other 12 39 Other Noncurrent Assets: Regulatory assets 1,032 1,041 Current Liabilities: Other 2 10 Current maturities of long-term debt 54 53 Long-Term Debt 1,082 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 renewables VIEs. (in millions) March 31, 2019 December 31, 2018 Current Assets: Other $ 140 $ 123 Property, plant and equipment, cost 4,018 4,007 Accumulated depreciation and amortization (733 ) (698 ) Other Noncurrent Assets: Other 280 261 Current maturities of long-term debt 173 174 Long-Term Debt 1,583 1,587 Other Noncurrent Liabilities: Asset Retirement Obligations 107 106 Other Noncurrent Liabilities: Other 212 212 NON-CONSOLIDATED VIEs The following tables summarize the impact of non-consolidated VIEs on the Condensed Consolidated Balance Sheets. March 31, 2019 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 67 $ 89 Investments in equity method unconsolidated affiliates 998 187 50 1,235 — — Total assets $ 998 $ 187 $ 50 $ 1,235 $ 67 $ 89 Taxes accrued (1 ) — — (1 ) — — Other current liabilities — — 2 2 — — Deferred income taxes 40 — — 40 — — Other noncurrent liabilities — — 11 11 — — Total liabilities $ 39 $ — $ 13 $ 52 $ — $ — Net assets $ 959 $ 187 $ 37 $ 1,183 $ 67 $ 89 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 power purchase agreement 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 $737 million , which represents 47 percent of the outstanding borrowings under the credit facility as of March 31, 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 March 31, December 31, Entity Name Interest 2019 2018 ACP (a) 47 % $ 973 $ 797 Constitution 24 % 25 25 Total $ 998 $ 822 (a) Duke Energy evaluated this investment for impairment as of March 31, 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 percent equity interest in Pioneer. Pioneer is considered a VIE due to having insufficient equity to finance its own activities without subordinated financial support. The activities that most significantly impact Pioneer's economic performance are decisions related to the development of new transmission facilities. The power to direct these activities is jointly and equally shared by Duke Energy and the other joint venture partner, American Electric Power; therefore, Duke Energy does not consolidate Pioneer. OVEC Duke Energy Ohio’s 9 percent 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 percent, 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) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Receivables sold $ 253 $ 269 $ 322 $ 336 Less: Retained interests 67 93 89 118 Net receivables sold $ 186 $ 176 $ 233 $ 218 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Three Months Ended March 31, March 31, (in millions) 2019 2018 2019 2018 Sales Receivables sold $ 575 $ 567 $ 734 $ 694 Loss recognized on sale 4 3 5 3 Cash flows Cash proceeds from receivables sold $ 597 $ 585 $ 758 $ 711 Return received on retained interests 2 2 3 2 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	3 Months Ended
	Mar. 31, 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 $ 86 $ 121 $ 87 $ 82 $ 39 $ 42 $ 457 Duke Energy Progress 7 9 9 9 9 9 52 Duke Energy Florida 79 112 78 73 30 33 405 Duke Energy Indiana 7 10 5 — — — 22 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 $ 53 $ 69 $ 65 $ 64 $ 61 $ 431 $ 743 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 March 31, 2019 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 2,370 $ 760 $ 1,114 $ 536 $ 578 $ 189 $ 306 $ — General 1,427 496 632 306 326 103 197 — Industrial 711 266 222 161 61 33 190 — Wholesale 541 119 353 315 38 14 54 — Other revenues 172 78 172 125 47 16 17 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 5,221 $ 1,719 $ 2,493 $ 1,443 $ 1,050 $ 355 $ 764 $ — Gas Utilities and Infrastructure Residential $ 414 $ — $ — $ — $ — $ 112 $ — $ 302 Commercial 206 — — — — 49 — 157 Industrial 48 — — — — 7 — 42 Power Generation — — — — — — — 13 Other revenues 63 — — — — 8 — 56 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 731 $ — $ — $ — $ — $ 176 $ — $ 570 Commercial Renewables Revenue from contracts with customers $ 42 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 4 $ — $ — $ — $ — $ — $ — $ — Total revenue from contracts with customers $ 5,998 $ 1,719 $ 2,493 $ 1,443 $ 1,050 $ 531 $ 764 $ 570 Other revenue sources (a) $ 165 $ 25 $ 79 $ 41 $ 36 $ — $ 4 $ 9 Total revenues $ 6,163 $ 1,744 $ 2,572 $ 1,484 $ 1,086 $ 531 $ 768 $ 579 Three Months Ended March 31, 2018 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 2,350 $ 781 $ 1,112 $ 516 $ 595 $ 180 $ 278 $ — General 1,375 472 631 299 333 96 178 — Industrial 664 255 208 145 62 30 173 — Wholesale 633 119 446 397 50 — 68 — Other revenues 139 67 129 85 43 14 17 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 5,161 $ 1,694 $ 2,526 $ 1,442 $ 1,083 $ 320 $ 714 $ — Gas Utilities and Infrastructure Residential $ 413 $ — $ — $ — $ — $ 111 $ — $ 302 Commercial 201 — — — — 49 — 152 Industrial 48 — — — — 7 — 41 Power Generation — — — — — — — 13 Other revenues 55 — — — — 6 — 49 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 717 $ — $ — $ — $ — $ 173 $ — $ 557 Commercial Renewables Revenue from contracts with customers $ 33 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 17 $ — $ — $ — $ — $ 14 $ — $ — Total revenue from contracts with customers $ 5,928 $ 1,694 $ 2,526 $ 1,442 $ 1,083 $ 507 $ 714 $ 557 Other revenue sources (a) $ 207 $ 69 $ 50 $ 18 $ 32 $ 17 $ 17 $ (4 ) Total revenues $ 6,135 $ 1,763 $ 2,576 $ 1,460 $ 1,115 $ 524 $ 731 $ 553 (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) March 31, 2019 December 31, 2018 Duke Energy $ 733 $ 896 Duke Energy Carolinas 281 313 Progress Energy 193 244 Duke Energy Progress 108 148 Duke Energy Florida 85 96 Duke Energy Ohio 1 2 Duke Energy Indiana 18 23 Piedmont 38 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) March 31, 2019 December 31, 2018 Duke Energy Ohio $ 62 $ 86 Duke Energy Indiana 109 128

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 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. The following table presents Duke Energy’s basic and diluted EPS calculations, the weighted average number of common shares outstanding and common share dividends declared. Three Months Ended March 31, (in millions, except per-share amounts) 2019 2018 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 898 $ 619 Weighted average shares outstanding – basic and diluted 727 701 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic and Diluted $ 1.24 $ 0.88 Potentially dilutive items excluded from the calculation (a) 2 2 Dividends declared per common share $ 0.9275 $ 0.89 (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 may issue and sell, through any of the Agents, shares of common stock through September 23, 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 . 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. 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 on a daily basis based on a floating interest rate factor and will decrease by other fixed amounts specified in the relevant forward sale agreements. Until settlement of the equity forwards, earnings per share 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 $974 million after issuance costs and the proceeds are being 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 percent per annum. Dividends are payable quarterly in arrears on the 16th day of March, June, September and December, beginning on June 16, 2019. Dividends issued on its 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. Dividends declared on preferred stock will be 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 will be a reduction to net income used in the calculation of basic and diluted EPS. The Series A Preferred Stock ranks, 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 Preferred Stock that is expressly made subordinated to the Series A Preferred Stock; • on a parity with any class or series of capital stock established after the original issue date of the Series A Preferred Stock that is not expressly made senior or subordinated to the Series A Preferred Stock; • junior to any class or series of capital stock established after the original issue date of the Series A Preferred Stock that is expressly made senior to the Series A 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. The 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 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. Holders of the 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 preferred stock include the right to vote as a single class 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. If dividends are deferred for a cumulative total of six quarterly full dividend periods, whether or not for consecutive dividend periods, holders of the preferred stock have the right to nominate two additional Board members to the Duke Energy Board of Directors.

Employee Benefit Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS DEFINED BENEFIT RETIREMENT PLANS Duke Energy and certain subsidiaries maintain, and the Subsidiary Registrants participate in, qualified 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. QUALIFIED PENSION PLANS The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 37 $ 12 $ 11 $ 6 $ 4 $ 1 $ 2 $ 1 Interest cost on projected benefit obligation 83 20 26 12 14 5 6 3 Expected return on plan assets (143 ) (38 ) (44 ) (23 ) (22 ) (8 ) (11 ) (5 ) Amortization of actuarial loss 24 6 9 3 6 1 2 2 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (3 ) Net periodic pension costs $ (7 ) $ (2 ) $ 1 $ (2 ) $ 2 $ (1 ) $ (1 ) $ (2 ) Three Months Ended March 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 45 $ 15 $ 13 $ 7 $ 5 $ 1 $ 2 $ 2 Interest cost on projected benefit obligation 75 18 24 11 13 5 6 3 Expected return on plan assets (140 ) (37 ) (45 ) (21 ) (23 ) (7 ) (10 ) (6 ) Amortization of actuarial loss 33 7 11 5 6 1 2 3 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (3 ) Net periodic pension costs $ 5 $ 1 $ 2 $ 2 $ 1 $ — $ — $ (1 ) NON-QUALIFIED PENSION PLANS Net periodic pension costs for non-qualified pension plans were not material for the three months ended March 31, 2019, and 2018. OTHER POST-RETIREMENT BENEFIT PLANS Net periodic costs for other post-retirement benefit plans were not material for the three months ended March 31, 2019, and 2018.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES EFFECTIVE TAX RATES The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended March 31, 2019 2018 Duke Energy 9.6 % 22.5 % Duke Energy Carolinas 17.7 % 22.0 % Progress Energy 17.3 % 13.2 % Duke Energy Progress 17.8 % 14.1 % Duke Energy Florida 19.3 % 16.3 % Duke Energy Ohio 16.9 % 32.4 % Duke Energy Indiana 24.1 % 25.9 % Piedmont 21.8 % 24.1 % The decrease in the ETR for Duke Energy is 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 the amortization of excess deferred taxes. This adjustment was immaterial and relates to prior years. The decrease in the ETR for Duke Energy Carolinas is primarily due to the amortization of excess deferred taxes. The increase in the ETR for Progress Energy is primarily due to a reduction in AFUDC equity and lower amortization of excess deferred taxes in the current year. The increase in the ETR for Duke Energy Progress is primarily due to lower amortization of excess deferred taxes in the current year. The increase in the ETR for Duke Energy Florida is primarily due to a reduction in AFUDC equity in the current year. The decrease in the ETR for Duke Energy Ohio is primarily due to the amortization of excess deferred taxes. The decrease in the ETR for Duke Energy Indiana is primarily due to the amortization of excess deferred taxes. The decrease in the ETR for Piedmont is primarily due to the amortization of excess deferred taxes.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on subsequent events related to the Commercial Renewables segment, regulatory matters, commitments and contingencies and stockholders' equity, see Notes 2, 3, 4 and 15, respectively.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Policy)	3 Months Ended
	Mar. 31, 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	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.
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 for additional information. Restricted cash amounts are included in Other within Current Assets and Other Noncurrent Assets on the Condensed Consolidated Balance Sheets.
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 March 31, 2019 , and an immaterial impact to the Duke Energy results of operations and cash flows for the three months ended March 31, 2019 . Duke Energy elected the modified retrospective method of adoption effective January 1, 2019. Under the modified retrospective method of adoption, prior year reported results are not restated. For adoption, Duke Energy 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. No new accounting standards that have been issued but not yet adopted are expected to have a material impact on the Duke Energy Registrants as of March 31, 2019 .
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. 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.
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. 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.
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.

Organization and Basis of Pre_3

Organization and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 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. March 31, 2019 December 31, 2018 Duke Duke Duke Progress Energy Duke Progress Energy Energy Energy Florida Energy Energy Florida Current Assets Cash and cash equivalents $ 377 $ 45 $ 8 $ 442 $ 67 $ 36 Other 134 12 12 141 39 39 Other Noncurrent Assets Other 39 38 — 8 6 — Total cash, cash equivalents and restricted cash $ 550 $ 95 $ 20 $ 591 $ 112 $ 75
Schedule of Utility Inventory	The components of inventory are presented in the tables below. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,231 $ 738 $ 1,033 $ 720 $ 313 $ 79 $ 321 $ 2 Coal 572 228 218 127 91 13 113 — Natural gas, oil and other fuel 299 41 213 112 101 19 1 23 Total inventory $ 3,102 $ 1,007 $ 1,464 $ 959 $ 505 $ 111 $ 435 $ 25 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 March 31, 2019 , and an immaterial impact to the Duke Energy results of operations and cash flows for the three months ended March 31, 2019 . Duke Energy elected the modified retrospective method of adoption effective January 1, 2019. Under the modified retrospective method of adoption, prior year reported results are not restated. For adoption, Duke Energy 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)	3 Months Ended
	Mar. 31, 2019
Segment Reporting Information [Line Items]
Business Segment Data	Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Three Months Ended March 31, 2019 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 5,321 $ 732 $ 106 $ 6,159 $ 4 $ — $ 6,163 Intersegment revenues 8 24 — 32 17 (49 ) — Total revenues $ 5,329 $ 756 $ 106 $ 6,191 $ 21 $ (49 ) $ 6,163 Segment income (loss) $ 750 $ 226 $ 13 $ 989 $ (89 ) $ — $ 900 Add back noncontrolling interest component (7 ) Net income $ 893 Segment assets $ 130,406 $ 12,639 $ 4,378 $ 147,423 $ 3,536 $ 177 $ 151,136 Three Months Ended March 31, 2018 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated revenues $ 5,315 $ 702 $ 101 $ 6,118 $ 17 $ — $ 6,135 Intersegment revenues 8 25 — 33 18 (51 ) — Total revenues $ 5,323 $ 727 $ 101 $ 6,151 $ 35 $ (51 ) $ 6,135 Segment income (loss) (a)(b)(c) $ 750 $ 116 $ 20 $ 886 $ (266 ) $ — $ 620 Add back noncontrolling interest component 2 Net income $ 622 (a) Electric Utilities and Infrastructure includes regulatory and legislative impairment charges related to rate case orders, settlements or other actions of regulators or legislative bodies. See Note 3 for additional information. (b) Gas Utilities and Infrastructure includes an impairment of the investment in Constitution. See Note 3 for additional information. (c) Other includes the loss on the sale of Beckjord described below, costs to achieve the Piedmont acquisition and a valuation allowance recorded against the AMT credits.
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data	Three Months Ended March 31, 2019 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 355 $ 176 $ 531 $ — $ — $ 531 Segment income/Net (loss) income $ 36 $ 35 $ 71 $ (2 ) $ — $ 69 Segment assets $ 6,058 $ 3,051 $ 9,109 $ 37 $ (2 ) $ 9,144 Three Months Ended March 31, 2018 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Total Total revenues $ 336 $ 174 $ 510 $ 14 $ 524 Segment income/Net loss (a) $ 33 $ 34 $ 67 $ (92 ) $ (25 ) (a) Other includes the loss on the sale of Beckjord described above.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	3 Months Ended
	Mar. 31, 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 due to a lack of requisite environmental control equipment. Dollar amounts in the table below are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets as of March 31, 2019 , and exclude capitalized asset retirement costs. Remaining Net Capacity Book Value (in MW) (in millions) Duke Energy Carolinas Allen Steam Station Units 1-3 (a) 585 $ 159 Duke Energy Indiana Gallagher Units 2 and 4 (b) 280 120 Total Duke Energy 865 $ 279 (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.

Commitments and Contingencies (

Commitments and Contingencies (Table)	3 Months Ended
	Mar. 31, 2019
Valuation and Qualifying Accounts Disclosure [Line Items]
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 $ 45 Duke Energy Carolinas 12 Duke Energy Ohio 22 Piedmont 2
Reserve, Environmental Cost [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Legal Reserves	The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Accounts Payable within Current Liabilities and Other within Other Noncurrent Liabilities on the Condensed Consolidated Balance Sheets. Three Months Ended March 31, 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 (2 ) 2 2 1 2 (6 ) — — Cash reductions (8 ) — — — — (8 ) — — Balance at end of period $ 67 $ 13 $ 13 $ 5 $ 8 $ 34 $ 5 $ 2 Three Months Ended March 31, 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 4 1 3 1 1 — 1 — Cash reductions (5 ) — (2 ) (1 ) (1 ) (3 ) — — Balance at end of period $ 80 $ 11 $ 16 $ 3 $ 12 $ 44 $ 6 $ 2
Reserve, Legal [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Legal 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) March 31, 2019 December 31, 2018 Reserves for Legal Matters Duke Energy $ 66 $ 65 Duke Energy Carolinas 8 9 Progress Energy 57 54 Duke Energy Progress 15 12 Duke Energy Florida 24 24 Piedmont 1 1

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Balance Sheet Amounts Recorded for Operating and Finance Leases	The following tables contain additional information related to leases. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Classification Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Assets Operating Operating Lease ROU Assets, net $ 1,698 $ 146 $ 835 $ 388 $ 447 $ 22 $ 61 $ 27 Finance Net property, plant and equipment 1,081 122 428 310 118 — 10 — Total lease assets $ 2,779 $ 268 $ 1,263 $ 698 $ 565 $ 22 $ 71 $ 27 Liabilities Current Operating Other current liabilities $ 183 $ 26 $ 89 $ 27 $ 62 $ 1 $ 4 $ 4 Finance Current maturities of long-term debt 121 6 23 6 17 1 — — Noncurrent Operating Operating Lease Liabilities 1,488 123 748 361 387 21 57 26 Finance Long-Term Debt 968 102 400 305 95 — 10 — Total lease liabilities $ 2,760 $ 257 $ 1,260 $ 699 $ 561 $ 23 $ 71 $ 30 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
Lease Costs and Cash Flows Information	Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Cash paid for amounts included in the measurement of lease liabilities (a) Operating cash flows from operating leases $ 67 $ 6 $ 31 $ 14 $ 17 $ 1 $ 2 $ 2 Operating cash flows from finance leases 17 4 6 4 2 — — — Financing cash flows from finance leases 27 1 3 1 2 — — — Lease assets obtained in exchange for new lease liabilities (non-cash) Finance $ 175 $ — $ 175 $ 175 $ — $ — $ — $ — Operating (b) 7 — — — — — — — (a) No amounts were classified as investing cash flows from operating leases for the three months ended March 31, 2019 . (b) Does not include ROU assets recorded as a result of the adoption of the new lease standard. The following table presents the components of lease expense. Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Operating lease expense (a) $ 72 $ 12 $ 42 $ 19 $ 23 $ 3 $ 5 $ 1 Short-term lease expense (a) 7 2 3 1 2 — 1 — Variable lease expense (a) 11 8 2 1 1 — — — Finance lease expense Amortization of leased assets (b) 27 1 3 1 2 — — — Interest on lease liabilities (c) 17 4 6 4 2 — — — Total finance lease expense 44 5 9 5 4 — — — Total lease expense $ 134 $ 27 $ 56 $ 26 $ 30 $ 3 $ 6 $ 1 (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.
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 March 31, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont 2020 $ 271 $ 32 $ 125 $ 47 $ 78 $ 2 $ 6 $ 5 2021 238 29 112 46 66 2 5 5 2022 192 19 90 35 55 2 4 5 2023 180 19 89 34 55 2 4 5 2024 169 16 89 35 54 2 4 5 Thereafter 1,057 66 530 309 221 22 67 9 Total operating lease payments 2,107 181 1,035 506 529 32 90 34 Less: present value discount (436 ) (32 ) (198 ) (118 ) (80 ) (10 ) (29 ) (4 ) Total operating lease liabilities (a) $ 1,671 $ 149 $ 837 $ 388 $ 449 $ 22 $ 61 $ 30 (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 non-cancelable 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 March 31, Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2020 $ 185 $ 19 $ 69 $ 44 $ 25 $ 1 $ 1 2021 191 18 69 44 25 — 1 2022 194 14 69 44 25 — 1 2023 179 14 69 44 25 — 1 2024 180 14 69 44 25 — 1 Thereafter 889 195 573 558 15 — 28 Total finance lease payments 1,818 274 918 778 140 1 33 Less: amount representing interest (729 ) (166 ) (495 ) (467 ) (28 ) — (23 ) Total finance lease liabilities $ 1,089 $ 108 $ 423 $ 311 $ 112 $ 1 $ 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	March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Weighted-average remaining lease term (years) Operating leases 11 9 11 13 9 18 19 7 Finance leases 13 19 16 18 11 — 27 — Weighted-average discount rate (a) Operating leases 3.9 % 3.7 % 3.8 % 3.9 % 3.7 % 4.2 % 4.1 % 3.6 % Finance leases 6.9 % 12.9 % 11.4 % 12.5 % 8.3 % 3.3 % 11.7 % — % (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)	3 Months Ended
	Mar. 31, 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 March 31, 2019 Unsecured Debt Duke Energy (Parent) September 2019 5.050 % $ 500 Piedmont September 2019 3.181 % (b) 350 Duke Energy Kentucky October 2019 4.650 % 100 Progress Energy December 2019 4.875 % 350 First Mortgage Bonds Duke Energy Ohio April 2019 5.450 % 450 Duke Energy Florida January 2020 1.850 % 250 Other (a) 501 Current maturities of long-term debt $ 2,501 (a) Includes finance lease obligations, amortizing debt and small bullet maturities. (b) Amount drawn under the Piedmont senior unsecured term loan facility has a floating interest rate. The following table summarizes significant debt issuances (in millions). Three Months Ended March 31, 2019 Duke Duke Duke Maturity Interest Duke Energy Energy Energy Issuance Date Date Rate Energy (Parent) Progress Ohio Unsecured Debt March 2019 (a) March 2022 3.251 % (b) $ 300 $ 300 $ — $ — March 2019 (a) March 2022 3.227 % 300 300 — — 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 — Total issuances $ 2,000 $ 600 $ 600 $ 800 (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.
Schedule Of Line Of Credit Facilities	The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. March 31, 2019 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Facility size (a) $ 8,000 $ 2,650 $ 1,750 $ 1,400 $ 650 $ 450 $ 600 $ 500 Reduction to backstop issuances Commercial paper (b) (2,657 ) (884 ) (859 ) (150 ) (299 ) (62 ) (252 ) (151 ) Outstanding letters of credit (53 ) (45 ) (4 ) (2 ) — — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity under the Master Credit Facility $ 4,709 $ 1,721 $ 637 $ 998 $ 351 $ 388 $ 267 $ 347 (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 March 31, 2019 (in millions) Facility size Amount Drawn Duke Energy (Parent) Three-Year Revolving Credit Facility $ 1,000 $ 500 Duke Energy Progress Term Loan Facility (a) 700 700 Piedmont Term Loan Facility 350 350 (a) $650 million was drawn under the term loan in January and February 2019.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	3 Months Ended
	Mar. 31, 2019
Asset Retirement Obligation [Abstract]
Schedule of Asset Retirement Obligations	The following table presents the AROs recorded on the Condensed Consolidated Balance Sheets. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Decommissioning of nuclear power facilities (a) $ 5,753 $ 2,368 $ 3,239 $ 2,709 $ 530 $ — $ — $ — Closure of ash impoundments 6,961 3,013 3,197 3,177 20 52 699 — Other 321 47 70 37 33 41 20 19 Total ARO $ 13,035 $ 5,428 $ 6,506 $ 5,923 $ 583 $ 93 $ 719 $ 19 Less: current portion 779 209 456 452 4 6 108 — Total noncurrent ARO $ 12,256 $ 5,219 $ 6,050 $ 5,471 $ 579 $ 87 $ 611 $ 19 (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) 110 48 57 50 7 1 7 — Liabilities settled (c) (184 ) (76 ) (97 ) (82 ) (15 ) (1 ) (10 ) — Revisions in estimates of cash flows (d) 2,642 1,507 1,135 1,135 — — — — Balance at March 31, 2019 $ 13,035 $ 5,428 $ 6,506 $ 5,923 $ 583 $ 93 $ 719 $ 19 (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 three months ended March 31, 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) Relates to increases in closure estimates for certain ash impoundments as a result of the NCDEQ's determination that all ash basins must be excavated. 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) March 31, 2019 December 31, 2018 Duke Energy $ 6,102 $ 5,579 Duke Energy Carolinas 3,443 3,133 Duke Energy Progress 2,659 2,446

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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)	3 Months Ended
	Mar. 31, 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 March 31, 2019 Intercompany income tax receivable $ 1 $ 65 $ — $ 22 $ 6 $ — $ — Intercompany income tax payable — — 11 — — 7 7 December 31, 2018 Intercompany income tax receivable $ 52 $ 47 $ 29 $ — $ — $ 8 $ — Intercompany income tax payable — — — 16 3 — 45 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 March 31, (in millions) 2019 2018 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 212 $ 220 Indemnification coverages (b) 5 6 JDA revenue (c) 23 34 JDA expense (c) 93 54 Intercompany natural gas purchases (d) 4 4 Progress Energy Corporate governance and shared service expenses (a) $ 176 $ 191 Indemnification coverages (b) 9 8 JDA revenue (c) 93 54 JDA expense (c) 23 34 Intercompany natural gas purchases (d) 19 19 Duke Energy Progress Corporate governance and shared service expenses (a) $ 106 $ 118 Indemnification coverages (b) 4 3 JDA revenue (c) 93 54 JDA expense (c) 23 34 Intercompany natural gas purchases (d) 19 19 Duke Energy Florida Corporate governance and shared service expenses (a) $ 70 $ 73 Indemnification coverages (b) 5 5 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 89 Indemnification coverages (b) 1 1 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 97 $ 101 Indemnification coverages (b) 2 2 Piedmont Corporate governance and shared service expenses (a) $ 32 $ 36 Indemnification coverages (b) 1 1 Intercompany natural gas sales (d) 23 23 Natural gas storage and transportation costs (e) 5 6 (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.

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 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. March 31, 2019 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 923 $ — $ — $ — $ — $ — Undesignated contracts 1,321 300 800 250 550 27 Total notional amount (a) $ 2,244 $ 300 $ 800 $ 250 $ 550 $ 27 December 31, 2018 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges $ 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 $422 million in cash flow hedges and $194 million in undesignated contracts as of March 31, 2019 , and 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. March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electricity (GWh) 6,196 — — — — 829 5,367 — Natural gas (millions of dekatherms) 742 128 174 174 — — 1 439 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 March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 16 $ 3 $ 5 $ 5 $ — $ 1 $ 5 $ 2 Noncurrent 6 2 3 3 — — — — Total Derivative Assets – Commodity Contracts $ 22 $ 5 $ 8 $ 8 $ — $ 1 $ 5 $ 2 Interest Rate Contracts Designated as Hedging Instruments Current $ 1 $ — $ — $ — $ — $ — $ — $ — Noncurrent 2 — — — — — — — Not Designated as Hedging Instruments Current 1 — — — — — — — Noncurrent 9 — — — — — — — Total Derivative Assets – Interest Rate Contracts $ 13 $ — $ — $ — $ — $ — $ — $ — Total Derivative Assets $ 35 $ 5 $ 8 $ 8 $ — $ 1 $ 5 $ 2 Derivative Liabilities March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 21 $ 12 $ 3 $ 3 $ — $ — $ — $ 6 Noncurrent 140 5 19 4 — — — 115 Total Derivative Liabilities – Commodity Contracts $ 161 $ 17 $ 22 $ 7 $ — $ — $ — $ 121 Interest Rate Contracts Designated as Hedging Instruments Current $ 25 $ — $ — $ — $ — $ — $ — $ — Noncurrent 9 — — — — — — — Not Designated as Hedging Instruments Current 42 22 19 3 17 1 — — Noncurrent 7 — 3 2 1 4 — — Total Derivative Liabilities – Interest Rate Contracts $ 83 $ 22 $ 22 $ 5 $ 18 $ 5 $ — $ — Total Derivative Liabilities $ 244 $ 39 $ 44 $ 12 $ 18 $ 5 $ — $ 121 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 March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 18 $ 3 $ 5 $ 5 $ — $ 1 $ 5 $ 2 Gross amounts offset (4 ) (2 ) (1 ) (1 ) — — — — Net amounts presented in Current Assets: Other $ 14 $ 1 $ 4 $ 4 $ — $ 1 $ 5 $ 2 Noncurrent Gross amounts recognized $ 17 $ 2 $ 3 $ 3 $ — $ — $ — $ — Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 14 $ 1 $ 1 $ 1 $ — $ — $ — $ — Derivative Assets December 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 38 $ 2 $ 2 $ 2 $ — $ 6 $ 23 $ 3 Gross amounts offset (3 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Assets: Other $ 35 $ — $ — $ — $ — $ 6 $ 23 $ 3 Noncurrent Gross amounts recognized $ 19 $ 1 $ 2 $ 2 $ — $ — $ — $ — Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 16 $ — $ — $ — $ — $ — $ — $ —
Offsetting Liabilities	Derivative Liabilities March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 88 $ 34 $ 22 $ 6 $ 17 $ 1 $ — $ 6 Gross amounts offset (4 ) (2 ) (2 ) (2 ) — — — — Net amounts presented in Current Liabilities: Other $ 84 $ 32 $ 20 $ 4 $ 17 $ 1 $ — $ 6 Noncurrent Gross amounts recognized $ 156 $ 5 $ 22 $ 6 $ 1 $ 4 $ — $ 115 Gross amounts offset (3 ) (1 ) (2 ) (2 ) — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 153 $ 4 $ 20 $ 4 $ 1 $ 4 $ — $ 115 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. March 31, 2019 Duke Duke Duke Energy Progress Energy (in millions) Energy Carolinas Energy Progress Aggregate fair value of derivatives in a net liability position $ 25 $ 14 $ 11 $ 11 Fair value of collateral already posted — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 25 14 11 11 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)	3 Months Ended
	Mar. 31, 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. March 31, 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 2,923 65 5,061 2,402 95 4,475 Corporate debt securities 17 2 624 4 13 566 Municipal bonds 5 1 317 1 4 353 U.S. government bonds 25 5 1,102 14 12 1,076 Other debt securities 1 1 145 — 2 148 Total NDTF Investments $ 2,971 $ 74 $ 7,363 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 51 $ — $ — $ 22 Equity securities 47 — 112 36 1 99 Corporate debt securities 1 — 57 — 2 60 Municipal bonds 2 1 89 — 1 85 U.S. government bonds 1 — 52 1 — 45 Other debt securities — 1 61 — 1 58 Total Other Investments $ 51 $ 2 $ 422 $ 37 $ 5 $ 369 Total Investments $ 3,022 $ 76 $ 7,785 $ 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. March 31, 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 2,923 65 5,061 2,402 95 4,475 Corporate debt securities 17 2 624 4 13 566 Municipal bonds 5 1 317 1 4 353 U.S. government bonds 25 5 1,102 14 12 1,076 Other debt securities 1 1 145 — 2 148 Total NDTF Investments $ 2,971 $ 74 $ 7,363 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 51 $ — $ — $ 22 Equity securities 47 — 112 36 1 99 Corporate debt securities 1 — 57 — 2 60 Municipal bonds 2 1 89 — 1 85 U.S. government bonds 1 — 52 1 — 45 Other debt securities — 1 61 — 1 58 Total Other Investments $ 51 $ 2 $ 422 $ 37 $ 5 $ 369 Total Investments $ 3,022 $ 76 $ 7,785 $ 2,458 $ 131 $ 7,075
Available-for-sale Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. March 31, 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 2,923 65 5,061 2,402 95 4,475 Corporate debt securities 17 2 624 4 13 566 Municipal bonds 5 1 317 1 4 353 U.S. government bonds 25 5 1,102 14 12 1,076 Other debt securities 1 1 145 — 2 148 Total NDTF Investments $ 2,971 $ 74 $ 7,363 $ 2,421 $ 126 $ 6,706 Other Investments Cash and cash equivalents $ — $ — $ 51 $ — $ — $ 22 Equity securities 47 — 112 36 1 99 Corporate debt securities 1 — 57 — 2 60 Municipal bonds 2 1 89 — 1 85 U.S. government bonds 1 — 52 1 — 45 Other debt securities — 1 61 — 1 58 Total Other Investments $ 51 $ 2 $ 422 $ 37 $ 5 $ 369 Total Investments $ 3,022 $ 76 $ 7,785 $ 2,458 $ 131 $ 7,075
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. March 31, 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 $ 74 $ 9 $ 41 $ 21 $ 20 $ 4 Due after one through five years 537 153 341 251 90 17 Due after five through 10 years 577 287 245 196 49 4 Due after 10 years 1,259 616 545 415 130 17 Total $ 2,447 $ 1,065 $ 1,172 $ 883 $ 289 $ 42
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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 35 $ 19 Realized losses 30 13 AFS: Realized gains 10 5 Realized losses 11 13
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. March 31, 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 $ — $ — $ 57 $ — $ — $ 29 Equity securities 1,593 37 2,791 1,309 54 2,484 Corporate debt securities 9 2 354 2 9 341 Municipal bonds 1 — 62 — 1 81 U.S. government bonds 11 3 509 5 8 475 Other debt securities 1 1 140 — 2 143 Total NDTF Investments $ 1,615 $ 43 $ 3,913 $ 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. March 31, 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 $ — $ — $ 57 $ — $ — $ 29 Equity securities 1,593 37 2,791 1,309 54 2,484 Corporate debt securities 9 2 354 2 9 341 Municipal bonds 1 — 62 — 1 81 U.S. government bonds 11 3 509 5 8 475 Other debt securities 1 1 140 — 2 143 Total NDTF Investments $ 1,615 $ 43 $ 3,913 $ 1,316 $ 74 $ 3,553
Available-for-sale Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. March 31, 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 $ — $ — $ 57 $ — $ — $ 29 Equity securities 1,593 37 2,791 1,309 54 2,484 Corporate debt securities 9 2 354 2 9 341 Municipal bonds 1 — 62 — 1 81 U.S. government bonds 11 3 509 5 8 475 Other debt securities 1 1 140 — 2 143 Total NDTF Investments $ 1,615 $ 43 $ 3,913 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 23 $ 10 Realized losses 21 5 AFS: Realized gains 9 5 Realized losses 10 10
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. March 31, 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 $ — $ — $ 57 $ — $ — $ 59 Equity securities 1,330 28 2,270 1,093 41 1,991 Corporate debt securities 8 — 270 2 4 225 Municipal bonds 4 1 255 1 3 272 U.S. government bonds 14 2 593 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,356 $ 31 $ 3,450 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 47 $ — $ — $ 17 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 96 $ — $ — $ 64 Total Investments $ 1,358 $ 31 $ 3,546 $ 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. March 31, 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 $ — $ — $ 57 $ — $ — $ 59 Equity securities 1,330 28 2,270 1,093 41 1,991 Corporate debt securities 8 — 270 2 4 225 Municipal bonds 4 1 255 1 3 272 U.S. government bonds 14 2 593 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,356 $ 31 $ 3,450 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 47 $ — $ — $ 17 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 96 $ — $ — $ 64 Total Investments $ 1,358 $ 31 $ 3,546 $ 1,105 $ 52 $ 3,217
Available-for-sale Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. March 31, 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 $ — $ — $ 57 $ — $ — $ 59 Equity securities 1,330 28 2,270 1,093 41 1,991 Corporate debt securities 8 — 270 2 4 225 Municipal bonds 4 1 255 1 3 272 U.S. government bonds 14 2 593 9 4 601 Other debt securities — — 5 — — 5 Total NDTF Investments $ 1,356 $ 31 $ 3,450 $ 1,105 $ 52 $ 3,153 Other Investments Cash and cash equivalents $ — $ — $ 47 $ — $ — $ 17 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 96 $ — $ — $ 64 Total Investments $ 1,358 $ 31 $ 3,546 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 12 $ 9 Realized losses 9 8 AFS: Realized gains 1 — Realized losses 1 3
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. March 31, 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 $ — $ — $ 43 $ — $ — $ 46 Equity securities 1,022 20 1,812 833 30 1,588 Corporate debt securities 6 — 204 2 3 171 Municipal bonds 4 1 254 1 3 271 U.S. government bonds 10 1 422 6 3 415 Other debt securities — — 3 — — 3 Total NDTF Investments $ 1,042 $ 22 $ 2,738 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 3 $ — $ — $ 6 Total Other Investments $ — $ — $ 3 $ — $ — $ 6 Total Investments $ 1,042 $ 22 $ 2,741 $ 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. March 31, 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 $ — $ — $ 43 $ — $ — $ 46 Equity securities 1,022 20 1,812 833 30 1,588 Corporate debt securities 6 — 204 2 3 171 Municipal bonds 4 1 254 1 3 271 U.S. government bonds 10 1 422 6 3 415 Other debt securities — — 3 — — 3 Total NDTF Investments $ 1,042 $ 22 $ 2,738 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 3 $ — $ — $ 6 Total Other Investments $ — $ — $ 3 $ — $ — $ 6 Total Investments $ 1,042 $ 22 $ 2,741 $ 842 $ 39 $ 2,500
Available-for-sale Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. March 31, 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 $ — $ — $ 43 $ — $ — $ 46 Equity securities 1,022 20 1,812 833 30 1,588 Corporate debt securities 6 — 204 2 3 171 Municipal bonds 4 1 254 1 3 271 U.S. government bonds 10 1 422 6 3 415 Other debt securities — — 3 — — 3 Total NDTF Investments $ 1,042 $ 22 $ 2,738 $ 842 $ 39 $ 2,494 Other Investments Cash and cash equivalents $ — $ — $ 3 $ — $ — $ 6 Total Other Investments $ — $ — $ 3 $ — $ — $ 6 Total Investments $ 1,042 $ 22 $ 2,741 $ 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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 10 $ 8 Realized losses 8 8 AFS: Realized gains 1 — Realized losses 1 2
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. March 31, 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 $ — $ — $ 14 $ — $ — $ 13 Equity securities 308 8 458 260 11 403 Corporate debt securities 2 — 66 — 1 54 Municipal bonds — — 1 — — 1 U.S. government bonds 4 1 171 3 1 186 Other debt securities — — 2 — — 2 Total NDTF Investments (a) $ 314 $ 9 $ 712 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 50 $ — $ — $ 48 Total Investments $ 316 $ 9 $ 762 $ 263 $ 13 $ 707 (a) During the three months ended March 31, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.
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. March 31, 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 $ — $ — $ 14 $ — $ — $ 13 Equity securities 308 8 458 260 11 403 Corporate debt securities 2 — 66 — 1 54 Municipal bonds — — 1 — — 1 U.S. government bonds 4 1 171 3 1 186 Other debt securities — — 2 — — 2 Total NDTF Investments (a) $ 314 $ 9 $ 712 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 50 $ — $ — $ 48 Total Investments $ 316 $ 9 $ 762 $ 263 $ 13 $ 707 (a) During the three months ended March 31, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.
Available-for-sale Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS. March 31, 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 $ — $ — $ 14 $ — $ — $ 13 Equity securities 308 8 458 260 11 403 Corporate debt securities 2 — 66 — 1 54 Municipal bonds — — 1 — — 1 U.S. government bonds 4 1 171 3 1 186 Other debt securities — — 2 — — 2 Total NDTF Investments (a) $ 314 $ 9 $ 712 $ 263 $ 13 $ 659 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Municipal bonds 2 — 49 — — 47 Total Other Investments $ 2 $ — $ 50 $ — $ — $ 48 Total Investments $ 316 $ 9 $ 762 $ 263 $ 13 $ 707 (a) During the three months ended March 31, 2019 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.
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 months ended March 31, 2019 , and 2018, were as follows. Three Months Ended (in millions) March 31, 2019 March 31, 2018 FV-NI: Realized gains $ 2 $ 1 Realized losses 1 — AFS: Realized losses — 1
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. March 31, 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 $ — $ 76 $ 29 $ — $ 67 Corporate debt securities — — 7 — — 8 Municipal bonds — 1 34 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 37 $ 1 $ 118 $ 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. March 31, 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 $ — $ 76 $ 29 $ — $ 67 Corporate debt securities — — 7 — — 8 Municipal bonds — 1 34 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 37 $ 1 $ 118 $ 29 $ 1 $ 108
Available-for-sale Securities	The following table presents the estimated fair value of investments in debt and equity securities; equity investments are measured at FV-NI and debt investments are classified as AFS. March 31, 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 $ — $ 76 $ 29 $ — $ 67 Corporate debt securities — — 7 — — 8 Municipal bonds — 1 34 — 1 33 U.S. government bonds — — 1 — — — Total Investments $ 37 $ 1 $ 118 $ 29 $ 1 $ 108

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the 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. March 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized NDTF equity securities $ 5,061 $ 4,998 $ — $ — $ 63 NDTF debt securities 2,302 630 1,672 — — Other equity securities 112 112 — — — Other debt securities 310 103 207 — — Derivative assets 35 2 27 6 — Total assets 7,820 5,845 1,906 6 63 Derivative liabilities (244 ) (23 ) (100 ) (121 ) — Net assets (liabilities) $ 7,576 $ 5,822 $ 1,806 $ (115 ) $ 63 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 March 31, (in millions) 2019 2018 Balance at beginning of period $ (113 ) $ (114 ) Purchases, sales, issuances and settlements: Settlements (12 ) (14 ) Total gains included on the Condensed Consolidated Balance Sheet 10 4 Balance at end of period $ (115 ) $ (124 )
Quantitative Information Table - Level 3	The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. March 31, 2019 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 1 RTO auction pricing FTR price – per MWh $ 0.17 - $ 2.40 Duke Energy Indiana FTRs 5 RTO auction pricing FTR price – per MWh (0.42 ) - 7.85 Piedmont Natural gas contracts (121 ) Discounted cash flow Forward natural gas curves – price per MMBtu 2.03 - 3.15 Duke Energy Total Level 3 derivatives $ (115 ) 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. March 31, 2019 December 31, 2018 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy (a) $ 56,182 $ 58,242 $ 54,529 $ 54,534 Duke Energy Carolinas 10,965 11,951 10,939 11,471 Progress Energy 19,251 20,942 18,911 19,885 Duke Energy Progress 9,048 9,469 8,204 8,300 Duke Energy Florida 7,265 8,000 7,321 7,742 Duke Energy Ohio 2,960 3,149 2,165 2,239 Duke Energy Indiana 3,722 4,242 3,782 4,158 Piedmont 2,138 2,243 2,138 2,180 (a) Book value of long-term debt includes $1.5 billion as of March 31, 2019 , and $1.6 billion as of December 31, 2018 , of unamortized debt discount and premium, net in purchase accounting adjustments related to the mergers with Progress Energy and Piedmont that are excluded from fair value of long-term debt.
Duke Energy Carolinas [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. March 31, 2019 (in millions) Total Fair Value Level 1 Level 2 Not Categorized NDTF equity securities $ 2,791 $ 2,728 $ — $ 63 NDTF debt securities 1,122 212 910 — Derivative assets 5 — 5 — Total assets 3,918 2,940 915 63 Derivative liabilities (39 ) — (39 ) — Net assets $ 3,879 $ 2,940 $ 876 $ 63 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 2,270 $ 2,270 $ — $ 1,991 $ 1,991 $ — NDTF debt securities 1,180 418 762 1,162 427 735 Other debt securities 96 47 49 64 17 47 Derivative assets 8 — 8 4 — 4 Total assets 3,554 2,735 819 3,221 2,435 786 Derivative liabilities (44 ) — (44 ) (44 ) — (44 ) Net assets $ 3,510 $ 2,735 $ 775 $ 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,812 $ 1,812 $ — $ 1,588 $ 1,588 $ — NDTF debt securities 926 298 628 906 294 612 Other debt securities 3 3 — 6 6 — Derivative assets 8 — 8 4 — 4 Total assets 2,749 2,113 636 2,504 1,888 616 Derivative liabilities (12 ) — (12 ) (27 ) — (27 ) Net assets $ 2,737 $ 2,113 $ 624 $ 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 458 $ 458 $ — $ 403 $ 403 $ — NDTF debt securities 254 120 134 256 133 123 Other debt securities 50 1 49 48 1 47 Total assets 762 579 183 707 537 170 Derivative liabilities (18 ) — (18 ) (9 ) — (9 ) Net assets $ 744 $ 579 $ 165 $ 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 for the three months ended March 31, 2019 , and 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. March 31, 2019 December 31, 2018 (in millions) Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Other equity securities $ 76 $ 76 $ — $ — $ 67 $ 67 $ — $ — Other debt securities 42 — 42 — 41 — 41 — Derivative assets 5 — — 5 23 1 — 22 Total assets $ 123 $ 76 $ 42 $ 5 $ 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 March 31, (in millions) 2019 2018 Balance at beginning of period $ 22 $ 27 Purchases, sales, issuances and settlements: Settlements (10 ) (14 ) Total losses included on the Condensed Consolidated Balance Sheet (7 ) (6 ) Balance at end of period $ 5 $ 7
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. March 31, 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 (121 ) — (121 ) (141 ) — (141 ) Net (liabilities) assets $ (119 ) $ 2 $ (121 ) $ (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 March 31, (in millions) 2019 2018 Balance at beginning of period $ (141 ) $ (142 ) Total gains and settlements 20 10 Balance at end of period $ (121 ) $ (132 )

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2019 350 475 325 250 Amounts borrowed at December 31, 2018 325 450 300 225 Restricted Receivables at March 31, 2019 534 630 495 317 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. March 31, 2019 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 67 $ 89 Investments in equity method unconsolidated affiliates 998 187 50 1,235 — — Total assets $ 998 $ 187 $ 50 $ 1,235 $ 67 $ 89 Taxes accrued (1 ) — — (1 ) — — Other current liabilities — — 2 2 — — Deferred income taxes 40 — — 40 — — Other noncurrent liabilities — — 11 11 — — Total liabilities $ 39 $ — $ 13 $ 52 $ — $ — Net assets $ 959 $ 187 $ 37 $ 1,183 $ 67 $ 89 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) March 31, 2019 December 31, 2018 Receivables of VIEs $ 5 $ 5 Regulatory Assets: Current 52 52 Current Assets: Other 12 39 Other Noncurrent Assets: Regulatory assets 1,032 1,041 Current Liabilities: Other 2 10 Current maturities of long-term debt 54 53 Long-Term Debt 1,082 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 renewables VIEs. (in millions) March 31, 2019 December 31, 2018 Current Assets: Other $ 140 $ 123 Property, plant and equipment, cost 4,018 4,007 Accumulated depreciation and amortization (733 ) (698 ) Other Noncurrent Assets: Other 280 261 Current maturities of long-term debt 173 174 Long-Term Debt 1,583 1,587 Other Noncurrent Liabilities: Asset Retirement Obligations 107 106 Other Noncurrent Liabilities: Other 212 212
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 March 31, December 31, Entity Name Interest 2019 2018 ACP (a) 47 % $ 973 $ 797 Constitution 24 % 25 25 Total $ 998 $ 822 (a) Duke Energy evaluated this investment for impairment as of March 31, 2019 , and December 31, 2018 , and determined that fair value approximated carrying value and therefore no impairment was necessary.
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) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Receivables sold $ 253 $ 269 $ 322 $ 336 Less: Retained interests 67 93 89 118 Net receivables sold $ 186 $ 176 $ 233 $ 218 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Three Months Ended March 31, March 31, (in millions) 2019 2018 2019 2018 Sales Receivables sold $ 575 $ 567 $ 734 $ 694 Loss recognized on sale 4 3 5 3 Cash flows Cash proceeds from receivables sold $ 597 $ 585 $ 758 $ 711 Return received on retained interests 2 2 3 2

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 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 $ 86 $ 121 $ 87 $ 82 $ 39 $ 42 $ 457 Duke Energy Progress 7 9 9 9 9 9 52 Duke Energy Florida 79 112 78 73 30 33 405 Duke Energy Indiana 7 10 5 — — — 22 Estimated remaining performance obligations are as follows: Remaining Performance Obligations (in millions) 2019 2020 2021 2022 2023 Thereafter Total Piedmont $ 53 $ 69 $ 65 $ 64 $ 61 $ 431 $ 743
Disaggregation of Revenue	Disaggregated revenues are presented as follows: Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 2,370 $ 760 $ 1,114 $ 536 $ 578 $ 189 $ 306 $ — General 1,427 496 632 306 326 103 197 — Industrial 711 266 222 161 61 33 190 — Wholesale 541 119 353 315 38 14 54 — Other revenues 172 78 172 125 47 16 17 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 5,221 $ 1,719 $ 2,493 $ 1,443 $ 1,050 $ 355 $ 764 $ — Gas Utilities and Infrastructure Residential $ 414 $ — $ — $ — $ — $ 112 $ — $ 302 Commercial 206 — — — — 49 — 157 Industrial 48 — — — — 7 — 42 Power Generation — — — — — — — 13 Other revenues 63 — — — — 8 — 56 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 731 $ — $ — $ — $ — $ 176 $ — $ 570 Commercial Renewables Revenue from contracts with customers $ 42 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 4 $ — $ — $ — $ — $ — $ — $ — Total revenue from contracts with customers $ 5,998 $ 1,719 $ 2,493 $ 1,443 $ 1,050 $ 531 $ 764 $ 570 Other revenue sources (a) $ 165 $ 25 $ 79 $ 41 $ 36 $ — $ 4 $ 9 Total revenues $ 6,163 $ 1,744 $ 2,572 $ 1,484 $ 1,086 $ 531 $ 768 $ 579 Three Months Ended March 31, 2018 Duke Duke Duke Duke Duke (in millions) Duke Energy Progress Energy Energy Energy Energy By market or type of customer Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Electric Utilities and Infrastructure Residential $ 2,350 $ 781 $ 1,112 $ 516 $ 595 $ 180 $ 278 $ — General 1,375 472 631 299 333 96 178 — Industrial 664 255 208 145 62 30 173 — Wholesale 633 119 446 397 50 — 68 — Other revenues 139 67 129 85 43 14 17 — Total Electric Utilities and Infrastructure revenue from contracts with customers $ 5,161 $ 1,694 $ 2,526 $ 1,442 $ 1,083 $ 320 $ 714 $ — Gas Utilities and Infrastructure Residential $ 413 $ — $ — $ — $ — $ 111 $ — $ 302 Commercial 201 — — — — 49 — 152 Industrial 48 — — — — 7 — 41 Power Generation — — — — — — — 13 Other revenues 55 — — — — 6 — 49 Total Gas Utilities and Infrastructure revenue from contracts with customers $ 717 $ — $ — $ — $ — $ 173 $ — $ 557 Commercial Renewables Revenue from contracts with customers $ 33 $ — $ — $ — $ — $ — $ — $ — Other Revenue from contracts with customers $ 17 $ — $ — $ — $ — $ 14 $ — $ — Total revenue from contracts with customers $ 5,928 $ 1,694 $ 2,526 $ 1,442 $ 1,083 $ 507 $ 714 $ 557 Other revenue sources (a) $ 207 $ 69 $ 50 $ 18 $ 32 $ 17 $ 17 $ (4 ) Total revenues $ 6,135 $ 1,763 $ 2,576 $ 1,460 $ 1,115 $ 524 $ 731 $ 553 (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) March 31, 2019 December 31, 2018 Duke Energy $ 733 $ 896 Duke Energy Carolinas 281 313 Progress Energy 193 244 Duke Energy Progress 108 148 Duke Energy Florida 85 96 Duke Energy Ohio 1 2 Duke Energy Indiana 18 23 Piedmont 38 73 These receivables for unbilled revenues are shown in the table below. (in millions) March 31, 2019 December 31, 2018 Duke Energy Ohio $ 62 $ 86 Duke Energy Indiana 109 128

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Schedule Of Earnings Per Share	The following table presents Duke Energy’s basic and diluted EPS calculations, the weighted average number of common shares outstanding and common share dividends declared. Three Months Ended March 31, (in millions, except per-share amounts) 2019 2018 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 898 $ 619 Weighted average shares outstanding – basic and diluted 727 701 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic and Diluted $ 1.24 $ 0.88 Potentially dilutive items excluded from the calculation (a) 2 2 Dividends declared per common share $ 0.9275 $ 0.89 (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)	3 Months Ended
	Mar. 31, 2019
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended March 31, 2019 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 37 $ 12 $ 11 $ 6 $ 4 $ 1 $ 2 $ 1 Interest cost on projected benefit obligation 83 20 26 12 14 5 6 3 Expected return on plan assets (143 ) (38 ) (44 ) (23 ) (22 ) (8 ) (11 ) (5 ) Amortization of actuarial loss 24 6 9 3 6 1 2 2 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (3 ) Net periodic pension costs $ (7 ) $ (2 ) $ 1 $ (2 ) $ 2 $ (1 ) $ (1 ) $ (2 ) Three Months Ended March 31, 2018 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 45 $ 15 $ 13 $ 7 $ 5 $ 1 $ 2 $ 2 Interest cost on projected benefit obligation 75 18 24 11 13 5 6 3 Expected return on plan assets (140 ) (37 ) (45 ) (21 ) (23 ) (7 ) (10 ) (6 ) Amortization of actuarial loss 33 7 11 5 6 1 2 3 Amortization of prior service credit (8 ) (2 ) (1 ) — — — — (3 ) Net periodic pension costs $ 5 $ 1 $ 2 $ 2 $ 1 $ — $ — $ (1 )

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Summary of Effective Tax Rates	The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended March 31, 2019 2018 Duke Energy 9.6 % 22.5 % Duke Energy Carolinas 17.7 % 22.0 % Progress Energy 17.3 % 13.2 % Duke Energy Progress 17.8 % 14.1 % Duke Energy Florida 19.3 % 16.3 % Duke Energy Ohio 16.9 % 32.4 % Duke Energy Indiana 24.1 % 25.9 % Piedmont 21.8 % 24.1 %

Organization and Basis of Pre_4

Organization and Basis of Presentation (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 377	$ 442
Other	134	141
Other Noncurrent Assets
Other	39	8
Total cash, cash equivalents and restricted cash	550	591	$ 579	$ 505
Progress Energy [Member]
Current Assets
Cash and cash equivalents	45	67
Other	12	39
Other Noncurrent Assets
Other	38	6
Total cash, cash equivalents and restricted cash	95	112	39	87
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	8	36
Other	12	39
Other Noncurrent Assets
Total cash, cash equivalents and restricted cash	$ 20	$ 75	$ 19	$ 53

Organization and Basis of Pre_5

Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Public Utilities, Inventory [Line Items]
Inventory	$ 3,102	$ 3,084
Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2,231	2,238
Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	572	491
Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	299	355
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,007	948
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	738	731
Duke Energy Carolinas [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	228	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	1,464	1,459
Progress Energy [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,033	1,049
Progress Energy [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	218	192
Progress Energy [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	213	218
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Inventory	959	954
Duke Energy Progress [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	720	734
Duke Energy Progress [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	127	106
Duke Energy Progress [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	112	114
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Inventory	505	504
Duke Energy Florida [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	313	315
Duke Energy Florida [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	91	86
Duke Energy Florida [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	101	103
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Inventory	111	126
Duke Energy Ohio [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	79	84
Duke Energy Ohio [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	13	14
Duke Energy Ohio [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	19	28
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Inventory	435	422
Duke Energy Indiana [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	321	312
Duke Energy Indiana [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	113	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	25	70
Piedmont Natural Gas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2	2
Piedmont Natural Gas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	$ 23	$ 68

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	Apr. 24, 2019USD ($)asset	Mar. 31, 2019USD ($)segment	Mar. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Pretax (gain) loss on disposal		$ 3	$ 100
Operation, maintenance and other		1,419	1,464
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Pretax (gain) loss on disposal			106
Operation, maintenance and other		$ 132	131
Number of reportable segments | segment		2
Beckjord [Member]
Segment Reporting Information [Line Items]
Pretax (gain) loss on disposal			106
Operation, maintenance and other			$ 1
Subsequent Event [Member] | Certain Renewable Assets [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Pretax proceeds from sale	$ 415
Subsequent Event [Member] | 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
Subsequent Event [Member] | Operating Solar assets [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Ownership percent divested	33.00%
Assets divested | asset	11

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating revenues	$ 6,163	$ 6,135
Segment income (loss)	900	620
Add back noncontrolling interest component	(7)	2
Net Income	893	622
Net income (attributable to parent)	900	620
Segment assets	151,136		$ 145,392
Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	5,321	5,315
Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	732	702
Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	106	101
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,159	6,118
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	4	17
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	989	886
Segment assets	147,423
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	5,329	5,323
Segment income (loss)	750	750
Segment assets	130,406
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	756	727
Segment income (loss)	226	116
Segment assets	12,639
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	106	101
Segment income (loss)	13	20
Segment assets	4,378
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,191	6,151
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(51)
Segment assets	177
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	8
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	24	25
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	32	33
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	17	18
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	(89)	(266)
Segment assets	3,536
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	21	35
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	531	524
Segment income (loss)	69	(25)
Net income (attributable to parent)	69	(25)
Segment assets	9,144		$ 8,555
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	355	336
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	176	174
Duke Energy Ohio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	531	510
Segment income (loss)	71	67
Segment assets	9,109
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	36	33
Segment assets	6,058
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	35	34
Segment assets	3,051
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment assets	(2)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues		14
Segment income (loss)	(2)	$ (92)
Segment assets	$ 37

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions

May 08, 2019USD ($)

May 01, 2019USD ($)

Apr. 30, 2019USD ($)

Apr. 09, 2019USD ($)

Apr. 02, 2019USD ($)

Apr. 01, 2019USD ($)

Mar. 25, 2019USD ($)

Jan. 30, 2019USD ($)

Dec. 27, 2018USD ($)

Nov. 08, 2018USD ($)

Aug. 31, 2018USD ($)

Jul. 31, 2018USD ($)

May 31, 2018USD ($)

Feb. 28, 2018

Feb. 15, 2018USD ($)

Nov. 22, 2017

Sep. 27, 2017USD ($)

Aug. 25, 2017USD ($)

Jun. 01, 2017USD ($)

Jun. 30, 2016

Dec. 22, 2015

Jan. 05, 2015

Sep. 02, 2014

Nov. 30, 2018USD ($)

May 31, 2018USD ($)

Dec. 31, 2015USD ($)

Mar. 31, 2019USD ($)MW

Mar. 31, 2018USD ($)

Jan. 28, 2019USD ($)

Dec. 31, 2018USD ($)

Oct. 31, 2018USD ($)customer

Sep. 28, 2018USD ($)

Mar. 28, 2018USD ($)

Sep. 30, 2017customer

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

$ 1,419

$ 1,464

Loss before income taxes

(988)

(803)

Public utilities, property, plant and equipment, net

95,721

$ 91,694

Regulated operating revenue, electric, non-nuclear

$ 5,285

5,284

Generation Facilities To Be Retired [Member]

Public Utilities, General Disclosures [Line Items]

Capacity (in MW) | MW

865

Public utilities, property, plant and equipment, net

$ 279

Atlantic Coast Pipeline (ACP) [Member]

Public Utilities, General Disclosures [Line Items]

Joint owner ownership percentage

47.00%

Long-term purchase commitment, period

20 years

Constitution Pipeline [Member]

Public Utilities, General Disclosures [Line Items]

Joint owner ownership percentage

24.00%

Estimated contributions

$ 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%

Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]

Public Utilities, General Disclosures [Line Items]

Estimated capital cost

$ 7,000

Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]

Public Utilities, General Disclosures [Line Items]

Estimated capital cost

7,800

Duke Energy Carolinas [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

440

451

Loss before income taxes

(356)

(414)

Public utilities, property, plant and equipment, net

31,030

29,245

Duke Energy Carolinas [Member] | 2017 North Carolina Rate Case [Member] | NCUC [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

4

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%

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%

Change in tax rate, deferred tax liability, income tax benefit

$ 66

Measurement period adjustment, income tax expense (benefit)

(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]

Regulatory assets

$ 242

Regulatory asset, amortization period

5 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]

Estimated loss on asset sale

$ 40

Duke Energy Progress [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

335

381

Loss before income taxes

(247)

(206)

Public utilities, property, plant and equipment, net

$ 21,889

20,398

Duke Energy Progress [Member] | Asheville Plant [Member] | Generation Facilities To Be Retired [Member]

Public Utilities, General Disclosures [Line Items]

Capacity (in MW) | MW

376

Public utilities, property, plant and equipment, net

$ 302

327

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%

Measurement period adjustment, income tax expense (benefit)

$ (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]

Regulatory assets

$ 51

Regulatory asset, amortization period

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 Florida [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

$ 230

237

Loss before income taxes

(119)

(123)

Public utilities, property, plant and equipment, net

14,108

13,824

Duke Energy Florida [Member] | Storm Costs [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory assets

157

217

Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]

Public Utilities, General Disclosures [Line Items]

Customers experiencing outages | customer

1,000,000

Allowed storm reserve

$ 132

132

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

213

165

$ 360

Property, plant and equipment, net

70

35

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 Ohio [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

132

131

Loss before income taxes

(83)

37

Public utilities, property, plant and equipment, net

6,803

6,643

Regulated operating revenue, electric, non-nuclear

355

336

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

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

Duke Energy Ohio [Member] | MGP Cost Recovery [Member] | PUCO [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory assets

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 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)

Duke Energy Indiana [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

189

181

Loss before income taxes

(145)

(135)

Public utilities, property, plant and equipment, net

$ 10,612

10,529

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

$ 80

82

Loss before income taxes

(156)

$ (145)

Public utilities, property, plant and equipment, net

$ 6,089

$ 5,911

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

Subsequent Event [Member] | 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

Subsequent Event [Member] | 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

Subsequent Event [Member] | Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]

Public Utilities, General Disclosures [Line Items]

Public utilities, approved equity capital structure, percentage

53.00%

Public utilities, approved debt capital structure, percentage

47.00%

Approved rate increase (decrease), amount

$ 107

Approved return on equity percentage

9.50%

Subsequent Event [Member] | 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

Subsequent Event [Member] | 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

Subsequent Event [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]

Public Utilities, General Disclosures [Line Items]

Public utilities, approved equity capital structure, percentage

53.00%

Public utilities, approved debt capital structure, percentage

47.00%

Approved rate increase (decrease), amount

$ 41

Approved return on equity percentage

9.50%

Subsequent Event [Member] | 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

Subsequent Event [Member] | Piedmont Natural Gas [Member] | North Carolina Rate Case 2019 [Member] | NCUC [Member]

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease), amount

$ 83

Requested rate increase, percentage

9.00%

North Carolina Department of Revenue [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]

Public Utilities, General Disclosures [Line Items]

Measurement period adjustment, income tax expense (benefit)

$ (17)

State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]

Public Utilities, General Disclosures [Line Items]

State and local taxes, reduction, amount

(17)

State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]

Public Utilities, General Disclosures [Line Items]

State and local taxes, reduction, amount

$ (12)

Scenario, Forecast [Member] | Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]

Public Utilities, General Disclosures [Line Items]

Operation, maintenance and other

$ (6)

Allowed storm reserve

24

Property, plant and equipment, net

$ 18

Scenario, Forecast [Member] | Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member]

Public Utilities, General Disclosures [Line Items]

Estimated storm costs - capital and operation maintenance

$ 221

Estimated storm costs - anticipated recovery period

12 months

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)MW	Dec. 31, 2018USD ($)
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	$ 95,721	$ 91,694
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	31,030	29,245
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	14,108	13,824
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	$ 10,612	$ 10,529
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	865
Public utilities, property, plant and equipment, net	$ 279
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	$ 159
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	$ 120

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)plantclaim	Dec. 31, 2018USD ($)	Dec. 31, 2016plant
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual	$ 66	$ 65
Coal Ash Insurance Coverage Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Number of NC and SC plants with ash basins | plant	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	9
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves	617	630
Reinsurance retention policy, excess retention, amount reinsured	764
Probable insurance recoveries	$ 739	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	139
Asbestos-related injuries and damages reserves	$ 34
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	57
Asbestos-related injuries and damages reserves	$ 18
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual	57	54
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual	15	12
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency accrual	24	$ 24
Duke Energy Florida [Member] | Fluor Contract Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Pending litigation, damages sought	110
Fluor Letter Of Credit [Member] | Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Drawings on credit facility	$ 67

Commitments and Contingencies_3

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	$ 77	$ 81
Provisions/adjustments	(2)	4
Cash reductions	(8)	(5)
Balance at end of period	67	80
Environmental exit costs, reasonably possible additional loss	45
Duke Energy Carolinas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	11	10
Provisions/adjustments	2	1
Cash reductions	0
Balance at end of period	13	11
Environmental exit costs, reasonably possible additional loss	12
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	11	15
Provisions/adjustments	2	3
Cash reductions		(2)
Balance at end of period	13	16
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	4	3
Provisions/adjustments	1	1
Cash reductions	0	(1)
Balance at end of period	5	3
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	6	12
Provisions/adjustments	2	1
Cash reductions	0	(1)
Balance at end of period	8	12
Duke Energy Ohio [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	48	47
Provisions/adjustments	(6)
Cash reductions	(8)	(3)
Balance at end of period	34	44
Environmental exit costs, reasonably possible additional loss	22
Duke Energy Indiana [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	5	5
Provisions/adjustments		1
Cash reductions	0
Balance at end of period	5	6
Piedmont Natural Gas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	2	2
Cash reductions	0
Balance at end of period	2	$ 2
Environmental exit costs, reasonably possible additional loss	$ 2

Commitments and Contingencies_4

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Reserves for legal matters	$ 66	$ 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	57	54
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	15	12
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	24	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	Mar. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
ROU assets	$ 1,698	$ 1,750
Operating lease liabilities – current	183	205
Operating lease liabilities – noncurrent	1,488	1,504
Duke Energy Carolinas [Member]
Lessee, Lease, Description [Line Items]
ROU assets	146	153
Operating lease liabilities – current	26	28
Operating lease liabilities – noncurrent	123	127
Progress Energy [Member]
Lessee, Lease, Description [Line Items]
ROU assets	835	863
Operating lease liabilities – current	89	96
Operating lease liabilities – noncurrent	748	766
Duke Energy Progress [Member]
Lessee, Lease, Description [Line Items]
ROU assets	388	407
Operating lease liabilities – current	27	35
Operating lease liabilities – noncurrent	361	371
Duke Energy Florida [Member]
Lessee, Lease, Description [Line Items]
ROU assets	447	456
Operating lease liabilities – current	62	61
Operating lease liabilities – noncurrent	387	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	61	61
Operating lease liabilities – current	4	4
Operating lease liabilities – noncurrent	57	58
Piedmont Natural Gas [Member]
Lessee, Lease, Description [Line Items]
ROU assets	27	26
Operating lease liabilities – current	4	4
Operating lease liabilities – noncurrent	$ 26	$ 25

Leases (Lease Costs) (Details)

Leases (Lease Costs) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 72
Short-term lease expense	7
Variable lease expense	11
Finance lease expense
Amortization of leased assets	27
Interest on lease liabilities	17
Total finance lease expense	44
Total lease expense	134
Duke Energy Carolinas [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	12
Short-term lease expense	2
Variable lease expense	8
Finance lease expense
Amortization of leased assets	1
Interest on lease liabilities	4
Total finance lease expense	5
Total lease expense	27
Progress Energy [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	42
Short-term lease expense	3
Variable lease expense	2
Finance lease expense
Amortization of leased assets	3
Interest on lease liabilities	6
Total finance lease expense	9
Total lease expense	56
Duke Energy Progress [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	19
Short-term lease expense	1
Variable lease expense	1
Finance lease expense
Amortization of leased assets	1
Interest on lease liabilities	4
Total finance lease expense	5
Total lease expense	26
Duke Energy Florida [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	23
Short-term lease expense	2
Variable lease expense	1
Finance lease expense
Amortization of leased assets	2
Interest on lease liabilities	2
Total finance lease expense	4
Total lease expense	30
Duke Energy Ohio [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	3
Finance lease expense
Total lease expense	3
Duke Energy Indiana [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	5
Short-term lease expense	1
Finance lease expense
Total lease expense	6
Piedmont Natural Gas [Member]
Lessee, Lease, Description [Line Items]
Operating lease expense	1
Finance lease expense
Total lease expense	$ 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	Mar. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due (Topic 842)
2020	$ 271
2021	238
2022	192
2023	180
2024	169
Thereafter	1,057
Total operating lease payments	2,107
Less: present value discount	(436)
Total operating lease liabilities	1,671
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	29
2022	19
2023	19
2024	16
Thereafter	66
Total operating lease payments	181
Less: present value discount	(32)
Total operating lease liabilities	149
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	125
2021	112
2022	90
2023	89
2024	89
Thereafter	530
Total operating lease payments	1,035
Less: present value discount	(198)
Total operating lease liabilities	837
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	47
2021	46
2022	35
2023	34
2024	35
Thereafter	309
Total operating lease payments	506
Less: present value discount	(118)
Total operating lease liabilities	388
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	66
2022	55
2023	55
2024	54
Thereafter	221
Total operating lease payments	529
Less: present value discount	(80)
Total operating lease liabilities	449
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	5
2022	4
2023	4
2024	4
Thereafter	67
Total operating lease payments	90
Less: present value discount	(29)
Total operating lease liabilities	61
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	9
Total operating lease payments	34
Less: present value discount	(4)
Total operating lease liabilities	$ 30
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	Mar. 31, 2019	Dec. 31, 2018
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	$ 185
2021	191
2022	194
2023	179
2024	180
Thereafter	889
Total finance lease payments	1,818
Less: amount representing interest	(729)
Total finance lease liabilities	1,089
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	18
2022	14
2023	14
2024	14
Thereafter	195
Total finance lease payments	274
Less: amount representing interest	(166)
Total finance lease liabilities	108
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	69
Thereafter	573
Total finance lease payments	918
Less: amount representing interest	(495)
Total finance lease liabilities	423
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	558
Total finance lease payments	778
Less: amount representing interest	(467)
Total finance lease liabilities	311
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	25
Thereafter	15
Total finance lease payments	140
Less: amount representing interest	(28)
Total finance lease liabilities	112
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 842)
2020	1
Total finance lease payments	1
Total finance lease liabilities	1
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	28
Total finance lease payments	33
Less: amount representing interest	(23)
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	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Assets
Operating	$ 1,698	$ 1,750
Finance	1,081
Total lease assets	2,779
Current
Operating	183	205
Finance	121
Noncurrent
Operating	1,488	1,504
Finance	968
Total lease liabilities	2,760
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	67
Operating cash flows from finance leases	17
Financing cash flows from finance leases	27
Lease assets obtained in exchange for new lease liabilities (non-cash)
Finance	175
Operating(b)	$ 7
Weighted-average remaining lease term (years)
Operating leases	11 years
Finance leases	13 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	6.90%
Duke Energy Carolinas [Member]
Assets
Operating	$ 146	153
Finance	122
Total lease assets	268
Current
Operating	26	28
Finance	6
Noncurrent
Operating	123	127
Finance	102
Total lease liabilities	257
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	6
Operating cash flows from finance leases	4
Financing cash flows from finance leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	9 years
Finance leases	19 years
Weighted-average discount rate
Operating leases	3.70%
Finance leases	12.90%
Progress Energy [Member]
Assets
Operating	$ 835	863
Finance	428
Total lease assets	1,263
Current
Operating	89	96
Finance	23
Noncurrent
Operating	748	766
Finance	400
Total lease liabilities	1,260
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	31
Operating cash flows from finance leases	6
Financing cash flows from finance leases	3
Lease assets obtained in exchange for new lease liabilities (non-cash)
Finance	$ 175
Weighted-average remaining lease term (years)
Operating leases	11 years
Finance leases	16 years
Weighted-average discount rate
Operating leases	3.80%
Finance leases	11.40%
Duke Energy Progress [Member]
Assets
Operating	$ 388	407
Finance	310
Total lease assets	698
Current
Operating	27	35
Finance	6
Noncurrent
Operating	361	371
Finance	305
Total lease liabilities	699
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	14
Operating cash flows from finance leases	4
Financing cash flows from finance leases	1
Lease assets obtained in exchange for new lease liabilities (non-cash)
Finance	$ 175
Weighted-average remaining lease term (years)
Operating leases	13 years
Finance leases	18 years
Weighted-average discount rate
Operating leases	3.90%
Finance leases	12.50%
Duke Energy Florida [Member]
Assets
Operating	$ 447	456
Finance	118
Total lease assets	565
Current
Operating	62	61
Finance	17
Noncurrent
Operating	387	395
Finance	95
Total lease liabilities	561
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	17
Operating cash flows from finance leases	2
Financing cash flows from finance leases	$ 2
Weighted-average remaining lease term (years)
Operating leases	9 years
Finance leases	11 years
Weighted-average discount rate
Operating leases	3.70%
Finance leases	8.30%
Duke Energy Ohio [Member]
Assets
Operating	$ 22	23
Total lease assets	22
Current
Operating	1	1
Finance	1
Noncurrent
Operating	21	22
Total lease liabilities	23
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	$ 1
Weighted-average remaining lease term (years)
Operating leases	18 years
Finance leases	0 years
Weighted-average discount rate
Operating leases	4.20%
Finance leases	3.30%
Duke Energy Indiana [Member]
Assets
Operating	$ 61	61
Finance	10
Total lease assets	71
Current
Operating	4	4
Noncurrent
Operating	57	58
Finance	10
Total lease liabilities	71
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	$ 2
Weighted-average remaining lease term (years)
Operating leases	19 years
Finance leases	27 years
Weighted-average discount rate
Operating leases	4.10%
Finance leases	11.70%
Piedmont Natural Gas [Member]
Assets
Operating	$ 27	26
Total lease assets	27
Current
Operating	4	4
Noncurrent
Operating	26	$ 25
Total lease liabilities	30
Cash paid for amounts included in the measurement of lease liabilities(a)
Operating cash flows from operating leases	$ 2
Weighted-average remaining lease term (years)
Operating leases	7 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
	Mar. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Contingent lease payments	$ 64
Operating lease assets, cost basis	3,345
Operating lease assets, accumulated depreciation	$ 631

Debt and Credit Facilities (Nar

Debt and Credit Facilities (Narrative) (Details) - Revolving Credit Facility [Member]	Mar. 31, 2019USD ($)
Debt Instrument [Line Items]
Facility size	$ 8,000,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Facility size	1,750,000,000
Duke Energy Carolinas [Member] | USDOJ [Member] | North Carolina Ash Basins [Member]
Debt Instrument [Line Items]
Minimum master credit facility balance required	250,000,000
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Facility size	1,400,000,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Facility size	$ 500,000,000

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	1 Months Ended	3 Months Ended
	Apr. 30, 2018	Mar. 31, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Debt issuances		$ 2,000,000,000
Repayments of long-term debt		1,201,000,000	$ 487,000,000
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances		600,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Repayments of long-term debt		1,000,000	401,000,000
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances		600,000,000
Repayments of long-term debt		601,000,000
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Repayments of long-term debt		81,000,000	$ 80,000,000
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances		800,000,000
Duke Energy Ohio [Member] | April 2019 First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Repayments of long-term debt	$ 450,000,000
Unsecured Debt [Member] | March 2019 Debt Issuance 3.250% Coupon Due 2022 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 300,000,000
Interest rate		3.25075%
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] | 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
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] | 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

Debt and Credit Facilities (S_2

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,501	$ 3,406
Other debt obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 501
Parent Company [Member] | Unsecured Debt [Member] | Debt Maturing September 2019, 5.050% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.05%
Current maturities of long-term debt	$ 500
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 350	350
Piedmont Natural Gas [Member] | Unsecured Debt [Member] | Debt Maturing September 2019, 3.181% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	3.181%
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	$ 825	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 Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 551	551
Duke Energy Ohio [Member] | First Mortgage Bonds [Member] | Bonds Maturing April 2019, 5.450% Coupon [Member] [Member]
Debt Instrument [Line Items]
Interest rate	5.45%
Current maturities of long-term debt	$ 450
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 470	$ 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

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - Revolving Credit Facility [Member]	Mar. 31, 2019USD ($)
Line of Credit Facility [Line Items]
Facility size	$ 8,000,000,000
Commercial paper	(2,657,000,000)
Outstanding letters of credit	(53,000,000)
Tax exempt bonds	(81,000,000)
Coal ash set-aside	(500,000,000)
Available capacity	4,709,000,000
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	2,650,000,000
Commercial paper	(884,000,000)
Outstanding letters of credit	(45,000,000)
Available capacity	1,721,000,000
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility size	1,750,000,000
Commercial paper	(859,000,000)
Outstanding letters of credit	(4,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	637,000,000
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,400,000,000
Commercial paper	(150,000,000)
Outstanding letters of credit	(2,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	998,000,000
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	650,000,000
Commercial paper	(299,000,000)
Available capacity	351,000,000
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	450,000,000
Commercial paper	(62,000,000)
Available capacity	388,000,000
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600,000,000
Commercial paper	(252,000,000)
Tax exempt bonds	(81,000,000)
Available capacity	267,000,000
Piedmont Natural Gas [Member]
Line of Credit Facility [Line Items]
Facility size	500,000,000
Commercial paper	(151,000,000)
Outstanding letters of credit	(2,000,000)
Available capacity	347,000,000
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) - USD ($)	2 Months Ended	3 Months Ended
	Feb. 28, 2019	Mar. 31, 2019
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		1,400,000,000
Duke Energy Progress [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Facility size		700,000,000
Amount Drawn		700,000,000
Drawings on credit facility	$ 650,000,000
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size		500,000,000
Piedmont Natural Gas [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Facility size		350,000,000
Amount Drawn		$ 350,000,000
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	Mar. 31, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Total ARO	$ 13,035	$ 10,467
Less: current portion	779	919
Total noncurrent ARO	12,256	9,548
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,428	3,949
Less: current portion	209	290
Total noncurrent ARO	5,219	3,659
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,506	5,411
Less: current portion	456	514
Total noncurrent ARO	6,050	4,897
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,923	4,820
Less: current portion	452	509
Total noncurrent ARO	5,471	4,311
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	583	591
Less: current portion	4	5
Total noncurrent ARO	579	586
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	93	93
Less: current portion	6	6
Total noncurrent ARO	87	87
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	719	722
Less: current portion	108	109
Total noncurrent ARO	611	613
Piedmont Natural Gas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	19	19
Total noncurrent ARO	19	$ 19
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,753
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,368
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,239
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,709
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	530
Closure of Ash Impoundments [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,961
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,013
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,197
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,177
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	20
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	52
Closure of Ash Impoundments [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	699
Other [Member]
Asset Retirement Obligations [Line Items]
Total ARO	321
Other [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	47
Other [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	70
Other [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	37
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	41
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	$ 19

Asset Retirement Obligations _2

Asset Retirement Obligations (ARO Rollforward) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	$ 10,467
Accretion expense	110
Liabilities settled	(184)
Revision in estimates of cash flows	2,642
Balance at end of period	13,035
Duke Energy Carolinas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	3,949
Accretion expense	48
Liabilities settled	(76)
Revision in estimates of cash flows	1,507
Balance at end of period	5,428
Progress Energy [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	5,411
Accretion expense	57
Liabilities settled	(97)
Revision in estimates of cash flows	1,135
Balance at end of period	6,506
Duke Energy Progress [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	4,820
Accretion expense	50
Liabilities settled	(82)
Revision in estimates of cash flows	1,135
Balance at end of period	5,923
Duke Energy Florida [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	591
Accretion expense	7
Liabilities settled	(15)
Balance at end of period	583
Duke Energy Ohio [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	93
Accretion expense	1
Liabilities settled	(1)
Balance at end of period	93
Duke Energy Indiana [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	722
Accretion expense	7
Liabilities settled	(10)
Balance at end of period	719
Piedmont Natural Gas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	19
Balance at end of period	$ 19

Asset Retirement Obligations (N

Asset Retirement Obligations (NDTF Information) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	$ 6,102	$ 5,579
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	3,443	3,133
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	2,659	2,446
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Legally restricted NDTF investments, fair value	$ 2,659	$ 2,446

Goodwill (Rollforward of Goodwi

Goodwill (Rollforward of Goodwill) (Details) - USD ($) $ in Millions	Mar. 31, 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
Accumulated impairment charges		0
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
Accumulated impairment charges		0
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 balance, adjusted for accumulated impairment charges		$ 0

Goodwill (Narrative) (Details)

Goodwill (Narrative) (Details) - USD ($)	Mar. 31, 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
Accumulated impairment charges		0
Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	1,924,000,000	1,924,000,000
Accumulated impairment charges		0
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
	Mar. 31, 2019	Mar. 31, 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	$ 212	$ 220
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
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	23	34
Related party transaction, expenses from transactions with related party	93	54
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	4	4
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	176	191
Progress Energy [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	9	8
Progress Energy [Member] | JDA [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	93	54
Related party transaction, expenses from transactions with related party	23	34
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	19
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	106	118
Duke Energy Progress [Member] | Indemnification coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	3
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	93	54
Related party transaction, expenses from transactions with related party	23	34
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	19
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	70	73
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
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	85	89
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
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	97	101
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
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	32	36
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
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	23	23
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	$ 5	$ 6

Related Party Transactions (Int

Related Party Transactions (Intercompany Income Taxes) (Details) - Affiliated Entity [Member] - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Income taxes receivable	$ 1	$ 52
Progress Energy [Member]
Related Party Transaction [Line Items]
Income taxes receivable	65	47
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Income taxes receivable		29
Income tax payable	11
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Income taxes receivable	22
Income tax payable		16
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Income taxes receivable	6
Income tax payable		3
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Income taxes receivable		8
Income tax payable	7
Piedmont Natural Gas [Member]
Related Party Transaction [Line Items]
Income tax payable	$ 7	$ 45

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019USD ($)GWhMcf	Dec. 31, 2018USD ($)GWhMcf
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	6,196	15,286
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	742	739
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 2,244	$ 2,644
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	923	923
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	1,321	1,721
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	422	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	128	121
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 300	$ 300
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 300	$ 300
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	174	169
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 800	$ 1,200
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 800	$ 1,200
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	174	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	550	$ 550
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 550	$ 550
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	829	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	5,367	13,500
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	1	1
Piedmont Natural Gas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume (in millions of decatherms) | Mcf	439	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	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 35	$ 57
Location and fair value amounts of derivatives (Liability)	244	242
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	18	38
Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	19
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	88	68
Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	156	174
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	39
Location and fair value amounts of derivatives (Liability)	161	191
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	18
Location and fair value amounts of derivatives (Liability)	83	51
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)	1	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)	2	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)	25	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)	9	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)	16	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)	6	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)	21	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)	140	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)	1	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)	9	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)	42	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)	7	10
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	3
Location and fair value amounts of derivatives (Liability)	39	33
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	2
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	1
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	34	23
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	10
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	3
Location and fair value amounts of derivatives (Liability)	17	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)	3	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)	2	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)	12	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)	5	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)	8	4
Location and fair value amounts of derivatives (Liability)	44	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)	3	2
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	23
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	21
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	4
Location and fair value amounts of derivatives (Liability)	22	25
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	19
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)	5	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)	3	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)	3	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)	19	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)	19	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
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	4
Location and fair value amounts of derivatives (Liability)	12	27
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	2
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	16
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	11
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	4
Location and fair value amounts of derivatives (Liability)	7	11
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	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)	5	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)	3	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)	3	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)	4	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)	3	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)	2	5
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	9
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	17	8
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	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)	18	3
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)	0	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)	17	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)	1	1
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	6
Location and fair value amounts of derivatives (Liability)	5	5
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	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)	4	4
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	6
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	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)	1	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)	4	4
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	23
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	23
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	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)	5	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)	121	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)	6	8
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	115	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)	121	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)	6	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)	$ 115	$ 133

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 35	$ 57
Net amounts recognized on the Condensed Consolidated Balance Sheet	35	57
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	18	38
Gross amounts offset	(4)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	35
Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	17	19
Gross amounts offset	(3)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	16
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	3
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	2
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	1
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	4
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Gross amounts offset	(1)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Progress Energy [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	2
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	4
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Gross amounts offset	(1)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	2
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	6
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	23
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	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	Mar. 31, 2019	Dec. 31, 2018
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 244	$ 242
Net amounts recognized on the Condensed Consolidated Balance Sheet	244	242
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	88	68
Gross amounts offset	(4)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	84	64
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	156	174
Gross amounts offset	(3)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	153	171
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	39	33
Net amounts recognized on the Condensed Consolidated Balance Sheet	39	33
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	34	23
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	32	21
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	10
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	9
Progress Energy [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	44	44
Net amounts recognized on the Condensed Consolidated Balance Sheet	44	44
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	22	23
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	21
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	22	21
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	19
Duke Energy Progress [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	27
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	27
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	16
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	14
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	11
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	9
Duke Energy Florida [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	9
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	9
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	17	8
Net amounts recognized on the Condensed Consolidated Balance Sheet	17	8
Duke Energy Florida [Member] | Other Noncurrent 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]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	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	4	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	4
Piedmont Natural Gas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	121	141
Net amounts recognized on the Condensed Consolidated Balance Sheet	121	141
Piedmont Natural Gas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	8
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	8
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	115	133
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 115	$ 133

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Mar. 31, 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	$ 25	$ 44
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	25	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	14	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	14	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	11	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	11	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	11	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 11	$ 25

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	Mar. 31, 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	$ 3,022	$ 2,458
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	76	131
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	7,785	7,075
Debt securities, available-for-sale	2,447
Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	2,923	2,402
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	2,971	2,421
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	74	126
Cash and cash equivalents	114	88
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	7,363	6,706
Equity Securities, FV-NI, Accumulated Unrealized Loss	65	95
Equity securities, FV-NI	5,061	4,475
Debt securities, available-for-sale	2,302	2,231
Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	47	36
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	51	37
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	2	5
Cash and cash equivalents	51	22
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	422	369
Equity Securities, FV-NI, Accumulated Unrealized Loss		1
Equity securities, FV-NI	112	99
Debt securities, available-for-sale	310	270
Duke Energy Carolinas [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Debt securities, available-for-sale	1,065
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	1,593	1,309
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,615	1,316
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	43	74
Cash and cash equivalents	57	29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,913	3,553
Equity Securities, FV-NI, Accumulated Unrealized Loss	37	54
Equity securities, FV-NI	2,791	2,484
Debt securities, available-for-sale	1,122	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	1,358	1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	31	52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,546	3,217
Debt securities, available-for-sale	1,172
Progress Energy [Member] | Ndtf [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,330	1,093
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,356	1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	31	52
Cash and cash equivalents	57	59
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,450	3,153
Equity Securities, FV-NI, Accumulated Unrealized Loss	28	41
Equity securities, FV-NI	2,270	1,991
Debt securities, available-for-sale	1,180	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	2	0
Cash and cash equivalents	47	17
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	96	64
Debt securities, available-for-sale	96	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	1,042	842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	22	39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,741	2,500
Debt securities, available-for-sale	883
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	1,022	833
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,042	842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	22	39
Cash and cash equivalents	43	46
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,738	2,494
Equity Securities, FV-NI, Accumulated Unrealized Loss	20	30
Equity securities, FV-NI	1,812	1,588
Debt securities, available-for-sale	926	906
Duke Energy Progress [Member] | Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Cash and cash equivalents	3	6
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3	6
Debt securities, available-for-sale	3	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	316	263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	9	13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	762	707
Debt securities, available-for-sale	289
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	308	260
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	314	263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	9	13
Cash and cash equivalents	14	13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	712	659
Equity Securities, FV-NI, Accumulated Unrealized Loss	8	11
Equity securities, FV-NI	458	403
Debt securities, available-for-sale	254	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	2
Cash and cash equivalents	1	1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	50	48
Debt securities, available-for-sale	50	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	37	29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	1	1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	118	108
Equity securities, FV-NI	76	67
Debt securities, available-for-sale	42
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule Of Available For Sale Securities And Other Trading Assets [Line Items]
Equity securities, FV-NI	$ 76	$ 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
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	$ 35	$ 19
Equity securities, FV-NI, realized loss	30	13
Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	2,923		$ 2,402
Equity Securities, FV-NI, Accumulated Unrealized Loss	65		95
Equity securities, FV-NI	5,061		4,475
Other Classification [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	47		36
Equity Securities, FV-NI, Accumulated Unrealized Loss			1
Equity securities, FV-NI	112		99
Duke Energy Carolinas [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	23	10
Equity securities, FV-NI, realized loss	21	5
Duke Energy Carolinas [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,593		1,309
Equity Securities, FV-NI, Accumulated Unrealized Loss	37		54
Equity securities, FV-NI	2,791		2,484
Progress Energy [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	12	9
Equity securities, FV-NI, realized loss	9	8
Progress Energy [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,330		1,093
Equity Securities, FV-NI, Accumulated Unrealized Loss	28		41
Equity securities, FV-NI	2,270		1,991
Duke Energy Progress [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	10	8
Equity securities, FV-NI, realized loss	8	8
Duke Energy Progress [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,022		833
Equity Securities, FV-NI, Accumulated Unrealized Loss	20		30
Equity securities, FV-NI	1,812		1,588
Duke Energy Florida [Member]
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract]
Equity securities, FV-NI, realized gain	2	1
Equity securities, FV-NI, realized loss	1	$ 0
Duke Energy Florida [Member] | Ndtf [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	308		260
Equity Securities, FV-NI, Accumulated Unrealized Loss	8		11
Equity securities, FV-NI	458		403
Duke Energy Indiana [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Accumulated Unrealized Gain	37		29
Equity securities, FV-NI	76		67
Duke Energy Indiana [Member] | Other Classification [Member]
Equity Securities, FV-NI, Accumulated Unrealized Gain (Loss) [Abstract]
Equity securities, FV-NI	$ 76		$ 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
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	$ 2,447
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	10	$ 5
Debt securities, available-for-sale, realized loss	11	13
Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	2,302		$ 2,231
Other Classification [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	310		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	17		4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2		13
Debt securities, available-for-sale	624		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	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax			2
Debt securities, available-for-sale	57		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	5		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		4
Debt securities, available-for-sale	317		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	2		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		1
Debt securities, available-for-sale	89		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	25		14
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	5		12
Debt securities, available-for-sale	1,102		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	1		1
Debt securities, available-for-sale	52		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	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		2
Debt securities, available-for-sale	145		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 loss, before tax	1		1
Debt securities, available-for-sale	61		58
Duke Energy Carolinas [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,065
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	9	5
Debt securities, available-for-sale, realized loss	10	10
Duke Energy Carolinas [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,122		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	9		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2		9
Debt securities, available-for-sale	354		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	1		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0		1
Debt securities, available-for-sale	62		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	11		5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	3		8
Debt securities, available-for-sale	509		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	1		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		2
Debt securities, available-for-sale	140		143
Progress Energy [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,172
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	1	0
Debt securities, available-for-sale, realized loss	1	3
Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	1,180		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	96		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	8		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax			4
Debt securities, available-for-sale	270		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	4		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		3
Debt securities, available-for-sale	255		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	2		0
Debt securities, available-for-sale	49		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	14		9
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2		4
Debt securities, available-for-sale	593		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
Duke Energy Progress [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	883
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized gain	1	0
Debt securities, available-for-sale, realized loss	1	2
Duke Energy Progress [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	926		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	3		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	6		2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0		3
Debt securities, available-for-sale	204		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	4		1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		3
Debt securities, available-for-sale	254		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	10		6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		3
Debt securities, available-for-sale	422		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, accumulated gross unrealized gain, before tax	0		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0		0
Debt securities, available-for-sale	3		3
Duke Energy Florida [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	289
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract]
Debt securities, available-for-sale, realized loss	0	$ 1
Duke Energy Florida [Member] | Ndtf [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	254		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	50		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 gain, before tax	2		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0		1
Debt securities, available-for-sale	66		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, accumulated gross unrealized gain, before tax	0		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0		0
Debt securities, available-for-sale	1		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	2		0
Debt securities, available-for-sale	49		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	4		3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1		1
Debt securities, available-for-sale	171		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, accumulated gross unrealized gain, before tax	0		0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0		0
Debt securities, available-for-sale	2		2
Duke Energy Indiana [Member]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax [Abstract]
Debt securities, available-for-sale	42
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	7		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 loss, before tax	1		1
Debt securities, available-for-sale	34		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		$ 0

Investments in Debt and Equit_5

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	$ 3,022	$ 2,458
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	76	131
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	7,785	7,075
Debt securities, available-for-sale	2,447
Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	2,971	2,421
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	74	126
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	7,363	6,706
Debt securities, available-for-sale	2,302	2,231
Equity Securities, FV-NI, Accumulated Unrealized Gain	2,923	2,402
Equity Securities, FV-NI, Accumulated Unrealized Loss	65	95
Cash and cash equivalents	114	88
Equity securities, FV-NI	5,061	4,475
Ndtf [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	17	4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2	13
Debt securities, available-for-sale	624	566
Ndtf [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	5	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	4
Debt securities, available-for-sale	317	353
Ndtf [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	25	14
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	5	12
Debt securities, available-for-sale	1,102	1,076
Ndtf [Member] | Other debt obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	2
Debt securities, available-for-sale	145	148
Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	51	37
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	2	5
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	422	369
Debt securities, available-for-sale	310	270
Equity Securities, FV-NI, Accumulated Unrealized Gain	47	36
Equity Securities, FV-NI, Accumulated Unrealized Loss		1
Cash and cash equivalents	51	22
Equity securities, FV-NI	112	99
Other Classification [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax		2
Debt securities, available-for-sale	57	60
Other Classification [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	2	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	1
Debt securities, available-for-sale	89	85
Other Classification [Member] | US treasury and government [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	52	45
Other Classification [Member] | Other debt obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	1
Debt securities, available-for-sale	61	58
Duke Energy Carolinas [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	1,065
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	1,615	1,316
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	43	74
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,913	3,553
Debt securities, available-for-sale	1,122	1,069
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,593	1,309
Equity Securities, FV-NI, Accumulated Unrealized Loss	37	54
Cash and cash equivalents	57	29
Equity securities, FV-NI	2,791	2,484
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	9	2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2	9
Debt securities, available-for-sale	354	341
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	1
Debt securities, available-for-sale	62	81
Duke Energy Carolinas [Member] | Ndtf [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	11	5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	3	8
Debt securities, available-for-sale	509	475
Duke Energy Carolinas [Member] | Ndtf [Member] | Other debt obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	2
Debt securities, available-for-sale	140	143
Progress Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,358	1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	31	52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,546	3,217
Debt securities, available-for-sale	1,172
Progress Energy [Member] | Ndtf [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,356	1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	31	52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3,450	3,153
Debt securities, available-for-sale	1,180	1,162
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,330	1,093
Equity Securities, FV-NI, Accumulated Unrealized Loss	28	41
Cash and cash equivalents	57	59
Equity securities, FV-NI	2,270	1,991
Progress Energy [Member] | Ndtf [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	8	2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax		4
Debt securities, available-for-sale	270	225
Progress Energy [Member] | Ndtf [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	3
Debt securities, available-for-sale	255	272
Progress Energy [Member] | Ndtf [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	14	9
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	2	4
Debt securities, available-for-sale	593	601
Progress Energy [Member] | Ndtf [Member] | Other debt obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	5	5
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	2	0
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	96	64
Debt securities, available-for-sale	96	64
Cash and cash equivalents	47	17
Progress Energy [Member] | Other Classification [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	2	0
Debt securities, available-for-sale	49	47
Duke Energy Progress [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	1,042	842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	22	39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,741	2,500
Debt securities, available-for-sale	883
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	1,042	842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	22	39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	2,738	2,494
Debt securities, available-for-sale	926	906
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,022	833
Equity Securities, FV-NI, Accumulated Unrealized Loss	20	30
Cash and cash equivalents	43	46
Equity securities, FV-NI	1,812	1,588
Duke Energy Progress [Member] | Ndtf [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	6	2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	3
Debt securities, available-for-sale	204	171
Duke Energy Progress [Member] | Ndtf [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	3
Debt securities, available-for-sale	254	271
Duke Energy Progress [Member] | Ndtf [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	10	6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	3
Debt securities, available-for-sale	422	415
Duke Energy Progress [Member] | Ndtf [Member] | Other debt obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale	3	3
Duke Energy Progress [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	3	6
Debt securities, available-for-sale	3	6
Cash and cash equivalents	3	6
Duke Energy Florida [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	316	263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	9	13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	762	707
Debt securities, available-for-sale	289
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	314	263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	9	13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	712	659
Debt securities, available-for-sale	254	256
Equity Securities, FV-NI, Accumulated Unrealized Gain	308	260
Equity Securities, FV-NI, Accumulated Unrealized Loss	8	11
Cash and cash equivalents	14	13
Equity securities, FV-NI	458	403
Duke Energy Florida [Member] | Ndtf [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	2	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	1
Debt securities, available-for-sale	66	54
Duke Energy Florida [Member] | Ndtf [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale	1	1
Duke Energy Florida [Member] | Ndtf [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4	3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	1
Debt securities, available-for-sale	171	186
Duke Energy Florida [Member] | Ndtf [Member] | Other debt obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale	2	2
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	2
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	50	48
Debt securities, available-for-sale	50	48
Cash and cash equivalents	1	1
Duke Energy Florida [Member] | Other Classification [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	2	0
Debt securities, available-for-sale	49	47
Duke Energy Indiana [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain	37	29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss	1	1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI	118	108
Debt securities, available-for-sale	42
Equity Securities, FV-NI, Accumulated Unrealized Gain	37	29
Equity securities, FV-NI	76	67
Duke Energy Indiana [Member] | Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	7	8
Duke Energy Indiana [Member] | Municipal bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	1	1
Debt securities, available-for-sale	34	33
Duke Energy Indiana [Member] | US treasury and government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	1	0
Duke Energy Indiana [Member] | Other Classification [Member]
Debt Securities, Available-for-sale [Line Items]
Equity securities, FV-NI	$ 76	$ 67

Investments in Debt and Equit_6

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Mar. 31, 2019USD ($)
Debt Instrument [Line Items]
Due in one year or less	$ 74
Due after one through five years	537
Due after five through 10 years	577
Due after 10 years	1,259
Total	2,447
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	9
Due after one through five years	153
Due after five through 10 years	287
Due after 10 years	616
Total	1,065
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	41
Due after one through five years	341
Due after five through 10 years	245
Due after 10 years	545
Total	1,172
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	21
Due after one through five years	251
Due after five through 10 years	196
Due after 10 years	415
Total	883
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	20
Due after one through five years	90
Due after five through 10 years	49
Due after 10 years	130
Total	289
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	4
Due after one through five years	17
Due after five through 10 years	4
Due after 10 years	17
Total	$ 42

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 2,447
Derivative assets	35	$ 57
Total assets	7,820	7,132
Derivative liabilities	(244)	(242)
Net assets (liabilities)	7,576	6,890
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	4
Total assets	5,845	5,156
Derivative liabilities	(23)	(11)
Net assets (liabilities)	5,822	5,145
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	27	25
Total assets	1,906	1,883
Derivative liabilities	(100)	(90)
Net assets (liabilities)	1,806	1,793
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	6	28
Total assets	6	28
Derivative liabilities	(121)	(141)
Net assets (liabilities)	(115)	(113)
Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	63	65
Net assets (liabilities)	63	65
Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	5,061	4,475
Debt securities, available-for-sale	2,302	2,231
Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	4,998	4,410
Debt securities, available-for-sale	630	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	63	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	310	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	103	67
Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	207	203
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,065
Derivative assets	5	3
Total assets	3,918	3,556
Derivative liabilities	(39)	(33)
Net assets (liabilities)	3,879	3,523
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,940	2,568
Net assets (liabilities)	2,940	2,568
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	3
Total assets	915	923
Derivative liabilities	(39)	(33)
Net assets (liabilities)	876	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	63	65
Net assets (liabilities)	63	65
Duke Energy Carolinas [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,791	2,484
Debt securities, available-for-sale	1,122	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	2,728	2,419
Debt securities, available-for-sale	212	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	910	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	63	65
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,172
Derivative assets	8	4
Total assets	3,554	3,221
Derivative liabilities	(44)	(44)
Net assets (liabilities)	3,510	3,177
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	2,735	2,435
Derivative liabilities	0
Net assets (liabilities)	2,735	2,435
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	4
Total assets	819	786
Derivative liabilities	(44)	(44)
Net assets (liabilities)	775	742
Progress Energy [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,270	1,991
Debt securities, available-for-sale	1,180	1,162
Progress Energy [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,270	1,991
Debt securities, available-for-sale	418	427
Progress Energy [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	762	735
Progress Energy [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	96	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	47	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	49	47
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	883
Derivative assets	8	4
Total assets	2,749	2,504
Derivative liabilities	(12)	(27)
Net assets (liabilities)	2,737	2,477
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	2,113	1,888
Derivative liabilities	0
Net assets (liabilities)	2,113	1,888
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	4
Total assets	636	616
Derivative liabilities	(12)	(27)
Net assets (liabilities)	624	589
Duke Energy Progress [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	1,812	1,588
Debt securities, available-for-sale	926	906
Duke Energy Progress [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	1,812	1,588
Debt securities, available-for-sale	298	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	628	612
Duke Energy Progress [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	3	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	3	6
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	289
Total assets	762	707
Derivative liabilities	(18)	(9)
Net assets (liabilities)	744	698
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	579	537
Net assets (liabilities)	579	537
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	183	170
Derivative liabilities	(18)	(9)
Net assets (liabilities)	165	161
Duke Energy Florida [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	458	403
Debt securities, available-for-sale	254	256
Duke Energy Florida [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	458	403
Debt securities, available-for-sale	120	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	134	123
Duke Energy Florida [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	50	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	1	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	49	47
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	76	67
Debt securities, available-for-sale	42
Derivative assets	5	23
Total assets	123	131
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	1
Total assets	76	68
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	42	41
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	22
Total assets	5	22
Duke Energy Indiana [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	76	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	76	67
Piedmont Natural Gas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	3
Derivative liabilities	(121)	(141)
Net assets (liabilities)	(119)	(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	(121)	(141)
Net assets (liabilities)	(121)	(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	42	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	$ 42	$ 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
	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement, transfers between activity levels	$ 0	$ 0
Derivatives (net)
Balance at beginning of period	(113,000,000)	(114,000,000)
Purchases, sales, issuances and settlements:
Settlements	(12,000,000)	(14,000,000)
Total gains included on the Condensed Consolidated Balance Sheet	10,000,000	4,000,000
Balance at end of period	(115,000,000)	(124,000,000)
Duke Energy Indiana [Member]
Derivatives (net)
Balance at beginning of period	22,000,000	27,000,000
Purchases, sales, issuances and settlements:
Settlements	(10,000,000)	(14,000,000)
Total gains included on the Condensed Consolidated Balance Sheet	(7,000,000)	(6,000,000)
Balance at end of period	5,000,000	7,000,000
Piedmont Natural Gas [Member]
Derivatives (net)
Balance at beginning of period	(141,000,000)	(142,000,000)
Purchases, sales, issuances and settlements:
Total gains and settlements	20,000,000	10,000,000
Balance at end of period	$ (121,000,000)	$ (132,000,000)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosures) (Details) $ in Millions	Mar. 31, 2019USD ($)$ / MWh$ / MMBTU	Dec. 31, 2018USD ($)$ / MWh$ / MMBTU	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ (115)	$ (113)	$ (124)	$ (114)
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ 1	$ 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	0.17	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	2.40	4.59
Duke Energy Indiana [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ 5	$ 22	7	27
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ 5	$ 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	(0.42)	(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	7.85	8.27
Piedmont Natural Gas [Member]
Fair Value Measurement Inputs and Valuation Techniques
Net derivative asset (liability)	$ (121)	$ (141)	$ (132)	$ (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)	$ (121)	$ (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	2.03	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	3.15	2.95

Fair Value Measurements (Other

Fair Value Measurements (Other Fair Value Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	$ 56,182	$ 54,529
Long-term debt, fair value	58,242	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	10,965	10,939
Long-term debt, fair value	11,951	11,471
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	19,251	18,911
Long-term debt, fair value	20,942	19,885
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	9,048	8,204
Long-term debt, fair value	9,469	8,300
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	7,265	7,321
Long-term debt, fair value	8,000	7,742
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	2,960	2,165
Long-term debt, fair value	3,149	2,239
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	3,722	3,782
Long-term debt, fair value	4,242	4,158
Piedmont Natural Gas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, book value	2,138	2,138
Long-term debt, fair value	$ 2,243	$ 2,180

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2017
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable interest entity, financial or other support, amount	$ 0	$ 0
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%
OVEC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable interest entity ownership interest	9.00%
Duke Energy Indiana [Member] | Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%
Atlantic Coast Pipeline [Member] | Financial Guarantee [Member]
Variable Interest Entities [Line Items]
Maximum potential amount of future payments associated with guarantees	$ 737,000,000
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	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Long-Term Debt	$ 53,681	$ 51,123
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	10,658	10,633
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	8,893	7,451
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	$ 6,795	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	$ 534	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	$ 630	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	$ 495	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	$ 317	$ 357

Variable Interest Entities (S_2

Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	$ 1,957	$ 2,005
Other, current assets	976	1,049
Regulatory assets, noncurrent	13,301	13,617
Property, plant and equipment, cost	139,377	134,458
Accumulated depreciation and amortization	(43,992)	(43,126)
Other noncurrent assets	2,969	2,935
Current Liabilities: Other	1,810	2,085
Current maturities of long-term debt	2,501	3,406
Long-Term Debt	53,681	51,123
Other Noncurrent Liabilities: Asset Retirement Obligations	12,256	9,548
Other Noncurrent Liabilities: Other	1,587	1,650
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	560	520
Other, current assets	31	72
Regulatory assets, noncurrent	3,429	3,457
Property, plant and equipment, cost	46,929	44,741
Accumulated depreciation and amortization	(15,899)	(15,496)
Other noncurrent assets	1,027	1,027
Current Liabilities: Other	415	571
Current maturities of long-term debt	7	6
Long-Term Debt	10,658	10,633
Other Noncurrent Liabilities: Asset Retirement Obligations	5,219	3,659
Other Noncurrent Liabilities: Other	645	671
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	622	703
Other, current assets	45	62
Regulatory assets, noncurrent	4,041	4,111
Property, plant and equipment, cost	33,188	31,459
Accumulated depreciation and amortization	(11,635)	(11,423)
Other noncurrent assets	627	612
Current Liabilities: Other	346	408
Current maturities of long-term debt	5	603
Long-Term Debt	8,893	7,451
Other Noncurrent Liabilities: Asset Retirement Obligations	5,471	4,311
Other Noncurrent Liabilities: Other	89	106
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	454	434
Other, current assets	55	46
Regulatory assets, noncurrent	2,316	2,454
Property, plant and equipment, cost	19,111	18,792
Accumulated depreciation and amortization	(5,003)	(4,968)
Other noncurrent assets	318	311
Current Liabilities: Other	426	406
Current maturities of long-term debt	470	270
Long-Term Debt	6,795	7,051
Other Noncurrent Liabilities: Asset Retirement Obligations	579	586
Other Noncurrent Liabilities: Other	95	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	5	5
Regulatory assets, current	52	52
Other, current assets	12	39
Regulatory assets, noncurrent	1,032	1,041
Current Liabilities: Other	2	10
Current maturities of long-term debt	54	53
Long-Term Debt	1,082	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	630	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	495	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	317	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	534	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	140	123
Property, plant and equipment, cost	4,018	4,007
Accumulated depreciation and amortization	(733)	(698)
Other noncurrent assets	280	261
Current maturities of long-term debt	173	174
Long-Term Debt	1,583	1,587
Other Noncurrent Liabilities: Asset Retirement Obligations	107	106
Other Noncurrent Liabilities: Other	$ 212	$ 212

Variable Interest Entities (S_3

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,602	$ 1,409
Taxes accrued	470	577
Current Liabilities: Other	1,810	2,085
Deferred income taxes	8,040	7,806
Other Noncurrent Liabilities: Other	1,587	1,650
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	1,235	1,060
Total assets	1,235	1,060
Taxes accrued	(1)	(1)
Current Liabilities: Other	2	4
Deferred income taxes	40	21
Other Noncurrent Liabilities: Other	11	12
Total liabilities	52	36
Net assets	1,183	1,024
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	998	822
Total assets	998	822
Taxes accrued	(1)	(1)
Deferred income taxes	40	21
Total liabilities	39	20
Net assets	959	802
Commercial Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	187	190
Total assets	187	190
Net assets	187	190
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	50	48
Total assets	50	48
Current Liabilities: Other	2	4
Other Noncurrent Liabilities: Other	11	12
Total liabilities	13	16
Net assets	37	32
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	79	114
Taxes accrued	157	202
Current Liabilities: Other	69	74
Deferred income taxes	842	817
Other Noncurrent Liabilities: Other	79	93
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	67	93
Total assets	67	93
Net assets	67	93
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	102	122
Taxes accrued	63	43
Current Liabilities: Other	92	107
Deferred income taxes	1,050	1,009
Other Noncurrent Liabilities: Other	29	16
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	89	118
Total assets	89	118
Net assets	$ 89	$ 118

Variable Interest Entities (Pip

Variable Interest Entities (Pipeline Investments) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 1,602	$ 1,409
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 1,235	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	$ 973	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	$ 998	$ 822

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold) (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 253	$ 269
Less: Retained interests	67	93
Net receivables sold	186	176
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	322	336
Less: Retained interests	89	118
Net receivables sold	$ 233	$ 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
	Mar. 31, 2019	Mar. 31, 2018
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 575	$ 567
Loss recognized on sale	4	3
Cash proceeds from receivables sold	597	585
Return received on retained interests	2	2
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	734	694
Loss recognized on sale	5	3
Cash proceeds from receivables sold	758	711
Return received on retained interests	$ 3	$ 2

Revenue (Remaining Performance

Revenue (Remaining Performance Obligations) (Details) $ in Millions	Mar. 31, 2019USD ($)
Progress Energy [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 86
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months
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, amount	$ 121
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 87
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 82
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 39
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 42
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	457
Duke Energy Progress [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 7
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months
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, amount	$ 9
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 9
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 9
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 9
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 9
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	52
Duke Energy Florida [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 79
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months
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, amount	$ 112
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 78
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 73
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 30
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, 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	405
Duke Energy Indiana [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 7
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months
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, amount	$ 10
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 5
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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	$ 22
Piedmont Natural Gas [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	53
Piedmont Natural Gas [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 69
Piedmont Natural Gas [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months
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, amount	$ 65
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 64
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 61
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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, amount	$ 431
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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	$ 743

Revenue (Disaggregation of Reve

Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 5,998	$ 5,928
Revenue from sources other than contracts with customers	165	207
Total operating revenues	6,163	6,135
Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,221	5,161
Total operating revenues	5,321	5,315
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,370	2,350
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,427	1,375
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	711	664
Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	541	633
Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	172	139
Gas Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	731	717
Total operating revenues	732	702
Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	414	413
Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	206	201
Gas Utilities and Infrastructure [Member] | Natural Gas, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	48	48
Gas Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	63	55
Commercial Renewables [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	42	33
Total operating revenues	106	101
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	17
Total operating revenues	4	17
Duke Energy Carolinas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,719	1,694
Revenue from sources other than contracts with customers	25	69
Total operating revenues	1,744	1,763
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,719	1,694
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	760	781
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	496	472
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	266	255
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	119	119
Duke Energy Carolinas [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	78	67
Progress Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,493	2,526
Revenue from sources other than contracts with customers	79	50
Total operating revenues	2,572	2,576
Progress Energy [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,493	2,526
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,114	1,112
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | General [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	632	631
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	222	208
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Electricity, US Regulated [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	353	446
Progress Energy [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	172	129
Duke Energy Progress [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,443	1,442
Revenue from sources other than contracts with customers	41	18
Total operating revenues	1,484	1,460
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,443	1,442
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	536	516
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	306	299
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	161	145
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	315	397
Duke Energy Progress [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	125	85
Duke Energy Florida [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,050	1,083
Revenue from sources other than contracts with customers	36	32
Total operating revenues	1,086	1,115
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,050	1,083
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	578	595
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	326	333
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	61	62
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	38	50
Duke Energy Florida [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47	43
Duke Energy Ohio [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	531	507
Revenue from sources other than contracts with customers		17
Total operating revenues	531	524
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	355	320
Total operating revenues	355	336
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	189	180
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	103	96
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	33	30
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	14
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	14
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	176	173
Total operating revenues	176	174
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	112	111
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	49	49
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	7	7
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8	6
Duke Energy Ohio [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		14
Duke Energy Indiana [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	764	714
Revenue from sources other than contracts with customers	4	17
Total operating revenues	768	731
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	764	714
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	306	278
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	197	178
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	190	173
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	54	68
Duke Energy Indiana [Member] | Electric Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	17	17
Piedmont Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	570	557
Revenue from sources other than contracts with customers	9	(4)
Total operating revenues	579	553
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	570	557
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	302	302
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	157	152
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	42	41
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
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 56	$ 49

Revenue (Unbilled Revenues) (De

Revenue (Unbilled Revenues) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 733	$ 896
Duke Energy Carolinas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	281	313
Progress Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	193	244
Duke Energy Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	108	148
Duke Energy Florida [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	85	96
Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	1	2
Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	18	23
Piedmont Natural Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	38	73
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	62	86
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 109	$ 128

Stockholders' Equity (Earnings

Stockholders' Equity (Earnings Per Share Data) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Equity [Abstract]
Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities	$ 898	$ 619
Weighted average shares outstanding - basic and diluted (in shares)	727	701
Earnings per share from continuing operations attributable to Duke Energy common stockholders, Basic and Diluted	$ 1.24	$ 0.88
Potentially dilutive items excluded from the calculation	2	2
Dividends declared per common share (usd per share)	$ 0.9275	$ 0.89

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	Mar. 31, 2019	Mar. 31, 2018	Dec. 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						$ 13	$ 21
Stock issued during period, shares, DRIP								2.2
Stock issued during period, value, DRIP								$ 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
ATM [Member] | JPMorgan Chase [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered			1.1			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					1.3
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
Subsequent Event [Member] | ATM [Member] | Citibank [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		$ 88.82

Stockholders' Equity (Preferred

Stockholders' Equity (Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 29, 2019	Mar. 31, 2019	Jun. 15, 2024
Class of Stock [Line Items]
Preferred stock, par value (in usd per share)	$ 0.001	$ 0.001
Proceeds from the issuance of preferred stock, net of issuance costs	$ 974	$ 974
Redemption price (in usd per share)		$ 25.50
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Shares issued (in shares)	40,000,000
Price per share (in usd per share)	$ 25
Liquidation preference per share (in usd per share)	$ 25
Cumulative dividend rate per annum	5.75%
Scenario, Forecast [Member]
Class of Stock [Line Items]
Redemption price (in usd per share)			$ 25

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - Qualified Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 37	$ 45
Interest cost on projected benefit obligation	83	75
Expected return on plan assets	(143)	(140)
Amortization of actuarial loss (gain)	24	33
Amortization of prior service (credit) cost	(8)	(8)
Net periodic costs	(7)	5
Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	12	15
Interest cost on projected benefit obligation	20	18
Expected return on plan assets	(38)	(37)
Amortization of actuarial loss (gain)	6	7
Amortization of prior service (credit) cost	(2)	(2)
Net periodic costs	(2)	1
Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	11	13
Interest cost on projected benefit obligation	26	24
Expected return on plan assets	(44)	(45)
Amortization of actuarial loss (gain)	9	11
Amortization of prior service (credit) cost	(1)	(1)
Net periodic costs	1	2
Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	6	7
Interest cost on projected benefit obligation	12	11
Expected return on plan assets	(23)	(21)
Amortization of actuarial loss (gain)	3	5
Net periodic costs	(2)	2
Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	4	5
Interest cost on projected benefit obligation	14	13
Expected return on plan assets	(22)	(23)
Amortization of actuarial loss (gain)	6	6
Net periodic costs	2	1
Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1
Interest cost on projected benefit obligation	5	5
Expected return on plan assets	(8)	(7)
Amortization of actuarial loss (gain)	1	1
Net periodic costs	(1)
Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	2
Interest cost on projected benefit obligation	6	6
Expected return on plan assets	(11)	(10)
Amortization of actuarial loss (gain)	2	2
Net periodic costs	(1)	0
Piedmont Natural Gas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	2
Interest cost on projected benefit obligation	3	3
Expected return on plan assets	(5)	(6)
Amortization of actuarial loss (gain)	2	3
Amortization of prior service (credit) cost	(3)	(3)
Net periodic costs	$ (2)	$ (1)

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 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	9.60%	22.50%
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	17.70%	22.00%
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	17.30%	13.20%
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	17.80%	14.10%
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	19.30%	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	16.90%	32.40%
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	24.10%	25.90%
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	21.80%	24.10%