Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
	Oct. 03, 2016	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues		$ 6,115	$ 6,628	$ 5,643	$ 6,135	$ 5,799	$ 6,482	$ 5,555	$ 5,729	$ 24,521	$ 23,565	$ 22,743
Interest expense										2,094	1,986	1,916
Depreciation and amortization										4,074	3,527	3,294
Equity in earnings (losses) of unconsolidated affiliates										83	119	(15)
Income tax expense (benefit) from continuing operations										448	1,196	1,156
Segment income (loss)										2,647	3,065	2,571
Add back noncontrolling interests component										(22)	5	7
Income (Loss) From Discontinued Operations, net of tax		20	4	(5)		(2)	(2)	(2)		19	(6)	(408)
Net income (loss)		454	1,066	502	622	703	955	689	717	2,644	3,064	2,170
Net Income (Loss) Attributable to Parent		464	1,082	500	620	703	954	686	716	2,666	3,059	2,152
Tax Act										20	(112)
After-tax severance charges		187								187	15	118
After-tax loss on sale and retirement					(107)					(107)
Asset Impairment Charges										402	282	18
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										9,668	8,198	13,215
Segment assets		145,392				137,914				145,392	137,914	132,761
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues		505	469	459	524	497	471	437	518	1,957	1,923	1,944
Interest expense										92	91	86
Depreciation and amortization										268	261	233
Income tax expense (benefit) from continuing operations										43	59	78
Segment income (loss)										176	193	192
Income (Loss) From Discontinued Operations, net of tax							(1)				(1)	36
Net Income (Loss) Attributable to Parent		55	$ 100	46	(25)	65	55	$ 30	$ 42	176	192	228
Tax Act		2				(23)				2	(23)
After-tax severance charges		6								6		3
After-tax loss on sale and retirement					107					107
Asset Impairment Charges											1
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										827	686	476
Segment assets		8,555				7,875				8,555	7,875	7,528
Piedmont Natural Gas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Net Income (Loss) Attributable to Parent												20
Asset Impairment Charges											7
Segment Reporting Information Assets [Abstract]
Payments to Acquire Businesses, Gross	$ 5,000
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Income (Loss) From Discontinued Operations, net of tax												(534)
Asset Impairment Charges												194
Regulatory settlements [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Regulatory settlement charges				$ 179	$ 86	23	$ 135			265	158
Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										22,242	21,300	21,336
Equity in earnings (losses) of unconsolidated affiliates										6	5	5
Tax Act										24	231
Electric Utilities and Infrastructure [Member] | Regulatory settlements [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Regulatory settlement charges										202	98
Electric Utilities and Infrastructure [Member] | After-tax impairment charge [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Asset Impairment Charges, net of tax										46
Gas Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										1,783	1,743	875
Equity in earnings (losses) of unconsolidated affiliates										27	62	19
Tax Act										1	26
Gas Utilities and Infrastructure [Member] | Piedmont Natural Gas [Member]
Segment Reporting Information Assets [Abstract]
Payments to Acquire Businesses, Gross	$ 5,000
Gas Utilities and Infrastructure [Member] | After-tax impairment charge [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Asset Impairment Charges, net of tax										42
Commercial Renewables [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										477	460	484
Equity in earnings (losses) of unconsolidated affiliates										(1)	(5)	(82)
Tax Act										3	442
Asset Impairment Charges, net of tax										91	74
Asset Impairment Charges												71
Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										19	62	48
Tax Act										2	597
After-tax severance charges										144
After-tax loss on sale and retirement										82
Costs to achieve mergers, acquisition costs										65	64	329
Cost Savings Initiative, Net of tax												57
Other Segments [Member] | International Energy [Member]
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions												26
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										24,502	23,503	22,695
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										22,273	21,331	21,366
Interest expense										1,288	1,240	1,136
Depreciation and amortization										3,523	3,010	2,897
Equity in earnings (losses) of unconsolidated affiliates										5	5	5
Income tax expense (benefit) from continuing operations										799	1,355	1,672
Segment income (loss)										3,058	3,210	3,040
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										8,086	7,024	6,649
Segment assets		125,364				119,423				125,364	119,423	114,993
Operating Segments [Member] | Electric Utilities and Infrastructure [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										1,450	1,373	1,410
Interest expense										67	62	58
Depreciation and amortization										183	178	151
Income tax expense (benefit) from continuing operations										47	40	55
Segment income (loss)										186	138	154
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										655	491	322
Segment assets		5,643				5,066				5,643	5,066	4,782
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										1,881	1,836	901
Interest expense										106	105	46
Depreciation and amortization										245	231	115
Equity in earnings (losses) of unconsolidated affiliates										27	62	19
Income tax expense (benefit) from continuing operations										78	116	90
Segment income (loss)										274	319	152
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										1,133	907	5,519
Segment assets		12,361				11,462				12,361	11,462	10,760
Operating Segments [Member] | Gas Utilities and Infrastructure [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										506	508	503
Interest expense										24	28	27
Depreciation and amortization										85	83	80
Income tax expense (benefit) from continuing operations										24	39	44
Segment income (loss)										93	85	77
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										172	195	154
Segment assets		2,874				2,758				2,874	2,758	2,696
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										477	460	484
Interest expense										88	87	53
Depreciation and amortization										155	155	130
Equity in earnings (losses) of unconsolidated affiliates										(1)	(5)	(82)
Income tax expense (benefit) from continuing operations										(147)	(628)	(160)
Segment income (loss)										9	441	23
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										193	92	857
Segment assets		4,204				4,156				4,204	4,156	4,377
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										24,631	23,627	22,751
Interest expense										1,482	1,432	1,235
Depreciation and amortization										3,923	3,396	3,142
Equity in earnings (losses) of unconsolidated affiliates										31	62	(58)
Income tax expense (benefit) from continuing operations										730	843	1,602
Segment income (loss)										3,341	3,970	3,215
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										9,412	8,023	13,025
Segment assets		141,929				135,041				141,929	135,041	130,130
Operating Segments [Member] | Total Reportable Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										1,956	1,881	1,913
Interest expense										91	90	85
Depreciation and amortization										268	261	231
Income tax expense (benefit) from continuing operations										71	79	99
Segment income (loss)										279	223	231
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										827	686	476
Segment assets		8,517				7,824				8,517	7,824	7,478
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										(199)	(200)	(125)
Interest expense										(45)	(20)	(12)
Depreciation and amortization										(1)
Segment income (loss)												1
Segment Reporting Information Assets [Abstract]
Segment assets		188				188				188	188	188
Intersegment Eliminations [Member] | Duke Energy Ohio [Member]
Segment Reporting Information Assets [Abstract]
Segment assets						(15)					(15)	(12)
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										31	31	30
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										98	93	26
Intersegment Eliminations [Member] | Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										70	76	69
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										129	124	56
Corporate, Non-Segment [Member] | Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										89	138	117
Interest expense										657	574	693
Depreciation and amortization										152	131	152
Equity in earnings (losses) of unconsolidated affiliates										52	57	43
Income tax expense (benefit) from continuing operations										(282)	353	(446)
Segment income (loss)										(694)	(905)	(645)
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										256	175	190
Segment assets		3,275				2,685				3,275	2,685	2,443
Corporate, Non-Segment [Member] | Other Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues										1	42	31
Interest expense										1	1	1
Depreciation and amortization												2
Income tax expense (benefit) from continuing operations										(28)	(20)	(21)
Segment income (loss)										(103)	(30)	(39)
Segment Reporting Information Assets [Abstract]
Segment assets		$ 38				$ 66				38	66	62
Noncontrolling Interest [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Net income (loss)										(22)	$ 5	$ 18
Noncontrolling Interest [Member] | Commercial Renewables [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Asset Impairment Charges, net of tax										$ 2