Employee Benefit Plans (Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	$ 855	$ 969
Regulatory assets	14,637	14,062
Regulatory liabilities	17,363	16,406
Duke Energy Carolinas
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	50	73
Regulatory assets	3,479	3,469
Regulatory liabilities	7,685	7,008
Progress Energy
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	417	505
Regulatory assets	6,939	6,533
Regulatory liabilities	6,044	5,691
Duke Energy Progress
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	221	242
Regulatory assets	4,651	4,468
Regulatory liabilities	5,249	4,924
Duke Energy Florida
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	166	231
Regulatory assets	2,288	2,064
Regulatory liabilities	796	768
Duke Energy Ohio
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	109	113
Regulatory assets	707	649
Regulatory liabilities	801	813
Duke Energy Indiana
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	167	171
Regulatory assets	1,555	1,328
Regulatory liabilities	1,692	1,738
Piedmont
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	7	8
Regulatory assets	457	455
Regulatory liabilities	1,114	1,132
Pension Plan | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	1,071	780
Noncurrent pension liability	43	77
Net amount recognized	(1,028)	(703)
Regulatory assets	1,649	1,910
Accumulated other comprehensive (income) loss
Deferred income tax asset	(20)	(21)
Prior service credit	(1)	(2)
Net actuarial loss (gain)	92	100
Net amount recognized in accumulated other comprehensive income (loss)	71	77
Pension Plan | Duke Energy Carolinas | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	462	393
Net amount recognized	(462)	(393)
Regulatory assets	324	381
Pension Plan | Progress Energy | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	494	379
Noncurrent pension liability	1	45
Net amount recognized	(493)	(334)
Regulatory assets	563	691
Accumulated other comprehensive (income) loss
Net actuarial loss (gain)	1	2
Net amount recognized in accumulated other comprehensive income (loss)	1	2
Pension Plan | Duke Energy Progress | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	268	229
Net amount recognized	(268)	(229)
Regulatory assets	252	283
Pension Plan | Duke Energy Florida | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	219	143
Noncurrent pension liability	1	45
Net amount recognized	(218)	(98)
Regulatory assets	311	408
Pension Plan | Duke Energy Ohio | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	74	58
Noncurrent pension liability	86	88
Net amount recognized	12	30
Regulatory assets	93	110
Pension Plan | Duke Energy Indiana | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	100	79
Noncurrent pension liability	111	110
Net amount recognized	11	31
Regulatory assets	190	209
Pension Plan | Piedmont | Qualified Plan
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	61	50
Net amount recognized	(61)	(50)
Regulatory assets	75	80
Other Post-Retirement Benefit Plans
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	12	8
Current pension liability	9	9
Noncurrent pension liability	417	471
Net amount recognized	414	472
Regulatory assets	129	144
Regulatory liabilities	162	139
Accumulated other comprehensive (income) loss
Deferred income tax liability	3	3
Prior service credit	(1)	(1)
Net actuarial loss (gain)	(14)	(13)
Net amount recognized in accumulated other comprehensive income (loss)	(12)	(11)
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	14	35
Net amount recognized	14	35
Regulatory liabilities	44	32
Other Post-Retirement Benefit Plans | Progress Energy
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	5	6
Noncurrent pension liability	259	294
Net amount recognized	264	300
Regulatory assets	126	144
Other Post-Retirement Benefit Plans | Duke Energy Progress
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	3	4
Noncurrent pension liability	146	164
Net amount recognized	149	168
Regulatory assets	79	88
Other Post-Retirement Benefit Plans | Duke Energy Florida
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	2
Noncurrent pension liability	112	129
Net amount recognized	114	131
Regulatory assets	47	56
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	1	1
Current pension liability	1	2
Noncurrent pension liability	16	17
Net amount recognized	16	18
Regulatory assets	4
Regulatory liabilities	21	17
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	48	54
Net amount recognized	48	54
Regulatory assets	28	32
Regulatory liabilities	63	62
Other Post-Retirement Benefit Plans | Piedmont
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	12	7
Net amount recognized	(12)	(7)
Regulatory liabilities	$ 5	$ 3