Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
	Oct. 03, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		$ 5,577	$ 6,576	$ 5,213	$ 5,377	$ 5,075	$ 6,202	$ 5,302	$ 5,792	$ 22,743	$ 22,371	$ 22,509
Interest expense										1,916	1,527	1,529
Depreciation and amortization										3,294	3,053	2,969
Equity in earnings (losses) of unconsolidated affiliates										(15)	69	130
Income tax expense (benefit) from continuing operations										1,156	1,256	1,225
Segment income										2,571	2,645	2,533
Add back noncontrolling interests component										7	9	5
Income (Loss) From Discontinued Operations, net of tax		(598)	180	(112)	122	49	45	(29)	112	(408)	177	(649)
Net income (loss)		(222)	1,181	512	699	482	935	547	867	2,170	2,831	1,889
Net Income (Loss) Attributable to Parent		(227)	1,176	509	694	477	932	543	864	2,152	2,816	1,883
Impairment charges										18	106	81
Costs to achieve mergers		208	84	111	120	30	24	22	21	523	97
Current State and Local Tax Expense (Benefit)										(15)	(12)	56
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										13,215	8,363	5,528
Assets		132,761				121,156				132,761	121,156	120,557
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		511	489	428	516	452	462	405	586	1,944	1,905	1,913
Interest expense										86	79	86
Depreciation and amortization										233	227	214
Income tax expense (benefit) from continuing operations										78	81	43
Segment income										192	149	68
Income (Loss) From Discontinued Operations, net of tax			34		2		(2)	(65)	90	36	23	(563)
Net Income (Loss) Attributable to Parent		57	89	23	59	43	32	(52)	149	228	172	(495)
Impairment charges												94
Costs to achieve mergers		2	$ 2	$ 1	$ 1	1	$ 1	$ 1	$ 1	6	4
Current State and Local Tax Expense (Benefit)										(13)	(1)	3
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										476	399	322
Assets		7,528				7,097				7,528	7,097	9,993
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(125)	(112)	(112)
Interest expense										(12)	(9)	(24)
Segment income										1		18
Segment Reporting Information Assets [Abstract]
Assets		188				188				188	188	190
Intersegment Eliminations [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues												(1)
Interest expense												1
Segment income											(1)	(1)
Segment Reporting Information Assets [Abstract]
Assets		(12)				(9)				(12)	(9)	(243)
Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										21,336	21,489	21,655
Equity in earnings (losses) of unconsolidated affiliates										5	(2)	(1)
Electric Utilities and Infrastructure [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										21,366	21,521	21,691
Interest expense										1,136	1,074	1,057
Depreciation and amortization										2,897	2,735	2,686
Equity in earnings (losses) of unconsolidated affiliates										5	(2)	(1)
Income tax expense (benefit) from continuing operations										1,672	1,602	1,582
Segment income										3,040	2,819	2,714
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										6,649	6,852	4,642
Assets		114,993				109,097				114,993	109,097	104,119
Electric Utilities and Infrastructure [Member] | Operating Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										1,410	1,331	1,317
Interest expense										58	53	43
Depreciation and amortization										151	147	138
Income tax expense (benefit) from continuing operations										55	59	71
Segment income										154	118	122
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										322	264	193
Assets		4,782				4,534				4,782	4,534	4,428
Electric Utilities and Infrastructure [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(30)	(32)	(36)
Gas Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										875	536	573
Equity in earnings (losses) of unconsolidated affiliates										19	1	0
Gas Utilities and Infrastructure [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										901	541	578
Interest expense										46	25	37
Depreciation and amortization										115	79	73
Equity in earnings (losses) of unconsolidated affiliates										19	1
Income tax expense (benefit) from continuing operations										90	44	45
Segment income										152	73	80
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										5,519	234	121
Assets		10,760				2,637				10,760	2,637	2,512
Gas Utilities and Infrastructure [Member] | Operating Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										503	541	578
Interest expense										27	25	37
Depreciation and amortization										80	79	73
Income tax expense (benefit) from continuing operations										44	45	45
Segment income										77	73	80
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										154	135	107
Assets		2,696				2,516				2,696	2,516	2,487
Gas Utilities and Infrastructure [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(26)	(5)	(5)
Commercial Renewables [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										484	286	235
Equity in earnings (losses) of unconsolidated affiliates										(82)	(6)	8
Impairment charges										71
Commercial Renewables [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										484	286	236
Interest expense										53	44	50
Depreciation and amortization										130	104	90
Equity in earnings (losses) of unconsolidated affiliates										(82)	(6)	8
Income tax expense (benefit) from continuing operations										(160)	(128)	(88)
Segment income										23	52	53
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										857	1,019	514
Assets		4,377				3,861				4,377	3,861	2,981
Commercial Renewables [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues												(1)
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										22,695	22,311	22,463
Total Reportable Segments [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										22,751	22,348	22,505
Interest expense										1,235	1,143	1,144
Depreciation and amortization										3,142	2,918	2,849
Equity in earnings (losses) of unconsolidated affiliates										(58)	(7)	7
Income tax expense (benefit) from continuing operations										1,602	1,518	1,539
Segment income										3,215	2,944	2,847
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										13,025	8,105	5,277
Assets		130,130				115,595				130,130	115,595	109,612
Total Reportable Segments [Member] | Operating Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										1,913	1,872	1,895
Interest expense										85	78	80
Depreciation and amortization										231	226	211
Income tax expense (benefit) from continuing operations										99	104	116
Segment income										231	191	202
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										476	399	300
Assets		7,478				7,050				7,478	7,050	6,915
Total Reportable Segments [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(56)	(37)	(42)
Other Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										48	60	46
Other Segment [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(69)	(75)	(70)
Other Segment [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										117	135	116
Interest expense										693	393	409
Depreciation and amortization										152	135	120
Equity in earnings (losses) of unconsolidated affiliates										43	76	123
Income tax expense (benefit) from continuing operations										(446)	(262)	(314)
Segment income										(645)	(299)	(332)
Costs to achieve mergers										329
Cost Savings Initiative, Net of tax										57
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										190	258	251
Assets		2,443				5,373				2,443	5,373	10,755
Other Segment [Member] | Corporate, Non-Segment [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										31	33	19
Interest expense										1	1	5
Depreciation and amortization										2	1	3
Income tax expense (benefit) from continuing operations										(21)	(23)	(73)
Segment income										(39)	(41)	(133)
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions												22
Assets		$ 62				$ 56				62	56	3,321
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Equity in earnings (losses) of unconsolidated affiliates										43	76	123
Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Costs to achieve mergers											60
Cost Savings Initiative, Net of tax											77
Edwardsport IGCC Plant [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Litigation Settlement, Expense											58
Ohio Valley Electric Corporation [Member] | Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges												94
Ohio Valley Electric Corporation [Member] | Other [Member] | Corporate, Non-Segment [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges												94
Dan River [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Litigation Settlement, Expense												102
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges										194
International Energy [Member] | Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										26	$ 45	$ 67
Piedmont Natural Gas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Net Income (Loss) Attributable to Parent										$ 20
Segment Reporting Information Assets [Abstract]
Payments to Acquire Businesses, Gross	$ 5,000
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information Assets [Abstract]
Payments to Acquire Businesses, Gross	$ 5,000