Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	$ 23,868	$ 25,079	$ 24,521
Interest expense	2,162	2,204	2,094
Depreciation and amortization	4,705	4,548	4,074
Equity in (losses) earnings of unconsolidated affiliates	(2,005)	162	83
Income tax expense (benefit) from continuing operations	(236)	519	448
Segment income (loss)	1,263	3,714	2,647
Add back noncontrolling interests component	295	177	22
Add back preferred stock dividend	107	41
Loss from discontinued operations, net of tax	7	(7)	19
Net income (loss)	1,377	3,748	2,666
Capital expenditures	10,421	11,446	9,668
Segment assets	162,388	158,838	145,392
Segment Reporting Information Assets [Abstract]
After-tax severance charges	(85)	16	187
Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	1,858	1,940	1,957
Interest expense	102	109	92
Depreciation and amortization	278	265	268
Income tax expense (benefit) from continuing operations	43	40	43
Segment income (loss)	252	239	176
Loss from discontinued operations, net of tax		(1)
Net income (loss)	252	238	176
Capital expenditures	834	952	827
Segment assets	10,025	9,338	8,555
Segment Reporting Information Assets [Abstract]
After-tax severance charges			6
Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	(199)	(200)	(199)
Interest expense	(16)	(58)	(45)
Depreciation and amortization	(29)	(5)	(1)
Segment assets		188	188
Eliminations | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Segment assets	(2)
Electric Utilities and Infrastructure
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	21,687	22,798	22,242
Equity in (losses) earnings of unconsolidated affiliates	(1)	9	6
Segment Reporting Information Assets [Abstract]
After tax impairment charge	948
Reduction of prior year impairment	152
Tax Act				$ 24
Shareholder Contribution expense	16
Electric Utilities and Infrastructure | After-tax impairment charge
Segment Reporting Information Assets [Abstract]
After tax impairment charge			46
Electric Utilities and Infrastructure | Regulatory settlements
Segment Reporting Information Assets [Abstract]
Regulatory settlement charges			202
Electric Utilities and Infrastructure | Clemson University Combined Heat and Power Plant
Segment Reporting Information Assets [Abstract]
After tax impairment charge	19
Electric Utilities and Infrastructure | Gas Pipeline Assets
Segment Reporting Information Assets [Abstract]
After tax impairment charge	5
Electric Utilities and Infrastructure | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	21,720	22,831	22,273
Interest expense	1,320	1,345	1,288
Depreciation and amortization	4,068	3,951	3,523
Equity in (losses) earnings of unconsolidated affiliates	(1)	9	5
Income tax expense (benefit) from continuing operations	340	785	799
Segment income (loss)	2,669	3,536	3,058
Capital expenditures	7,629	8,263	8,086
Segment assets	138,225	135,561	125,364
Segment Reporting Information Assets [Abstract]
Reduction of prior year impairment		27
Electric Utilities and Infrastructure | Operating Segments | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	1,405	1,456	1,450
Interest expense	85	80	67
Depreciation and amortization	200	182	183
Income tax expense (benefit) from continuing operations	19	20	47
Segment income (loss)	162	159	186
Capital expenditures	548	680	655
Segment assets	6,615	6,188	5,643
Electric Utilities and Infrastructure | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	33	33	31
Gas Utilities and Infrastructure
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	1,653	1,770	1,783
Equity in (losses) earnings of unconsolidated affiliates	(2,017)	114	27
Segment Reporting Information Assets [Abstract]
After tax impairment charge	7
Tax Act				1
Gas Utilities and Infrastructure | After-tax impairment charge
Segment Reporting Information, Profit (Loss) [Abstract]
Equity in (losses) earnings of unconsolidated affiliates	2,100
Segment Reporting Information Assets [Abstract]
After tax impairment charge		19	42
Gas Utilities and Infrastructure | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	1,748	1,866	1,881
Interest expense	135	117	106
Depreciation and amortization	258	256	245
Equity in (losses) earnings of unconsolidated affiliates	(2,017)	114	27
Income tax expense (benefit) from continuing operations	(349)	22	78
Segment income (loss)	(1,266)	432	274
Capital expenditures	1,309	1,539	1,133
Segment assets	13,849	13,921	12,361
Gas Utilities and Infrastructure | Operating Segments | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	453	484	506
Interest expense	17	29	24
Depreciation and amortization	78	83	85
Income tax expense (benefit) from continuing operations	26	21	24
Segment income (loss)	96	85	93
Capital expenditures	286	272	172
Segment assets	3,380	3,116	2,874
Gas Utilities and Infrastructure | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	95	96	98
Commercial Renewables
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	502	487	477
Equity in (losses) earnings of unconsolidated affiliates		(4)	(1)
Segment Reporting Information Assets [Abstract]
Tax Act				3
Commercial Renewables | Noncontrolling Interests
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues			91
Segment Reporting Information Assets [Abstract]
After tax impairment charge			2
Commercial Renewables | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	502	487	477
Interest expense	66	95	88
Depreciation and amortization	199	168	155
Equity in (losses) earnings of unconsolidated affiliates		(4)	(1)
Income tax expense (benefit) from continuing operations	(65)	(115)	(147)
Segment income (loss)	286	198	9
Capital expenditures	1,219	1,423	193
Segment assets	6,716	6,020	4,204
Total Reportable Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	23,842	25,055	24,502
Total Reportable Segments | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	23,970	25,184	24,631
Interest expense	1,521	1,557	1,482
Depreciation and amortization	4,525	4,375	3,923
Equity in (losses) earnings of unconsolidated affiliates	(2,018)	119	31
Income tax expense (benefit) from continuing operations	(74)	692	730
Segment income (loss)	1,689	4,166	3,341
Capital expenditures	10,157	11,225	9,412
Segment assets	158,790	155,502	141,929
Total Reportable Segments | Operating Segments | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	1,858	1,940	1,956
Interest expense	102	109	91
Depreciation and amortization	278	265	268
Income tax expense (benefit) from continuing operations	45	41	71
Segment income (loss)	258	244	279
Capital expenditures	834	952	827
Segment assets	9,995	9,304	8,517
Total Reportable Segments | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	128	129	129
Other
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	26	24	19
Segment Reporting Information Assets [Abstract]
Tax Act				$ 2
Costs to achieve mergers, acquisition costs			65
Other | Other
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	97	95	89
Interest expense	657	705	657
Depreciation and amortization	209	178	152
Equity in (losses) earnings of unconsolidated affiliates	13	43	52
Income tax expense (benefit) from continuing operations	(162)	(173)	(282)
Segment income (loss)	(426)	(452)	(694)
Capital expenditures	264	221	256
Segment assets	3,598	3,148	3,275
Other | Other | Duke Energy Ohio
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues			1
Interest expense			1
Income tax expense (benefit) from continuing operations	(2)	(1)	(28)
Segment income (loss)	(6)	(5)	(103)
Segment assets	32	34	38
Other | Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues	71	71	70
Other
Segment Reporting Information, Profit (Loss) [Abstract]
Equity in (losses) earnings of unconsolidated affiliates	13	$ 43	51
Segment Reporting Information Assets [Abstract]
After-tax severance charges			144
Loss in disposal			$ 82
Severance Charge Reversal	$ 98