Revenue (Aging of Trade Receivables) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	$ 758	$ 969
Trade and Other Receivables, not past due	1,656	1,789
Deferred Payment Arrangements	170	215
Trade and Other Receivables	2,931	3,299
30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	181	185
60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	46	22
90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	120	119
Duke Energy Carolinas
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	293	328
Trade and Other Receivables, not past due	337	445
Deferred Payment Arrangements	80	96
Trade and Other Receivables	818	966
Duke Energy Carolinas | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	62	80
Duke Energy Carolinas | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	15	1
Duke Energy Carolinas | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	31	16
Progress Energy
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	183	283
Trade and Other Receivables, not past due	633	707
Deferred Payment Arrangements	53	80
Trade and Other Receivables	952	1,166
Progress Energy | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	46	54
Progress Energy | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	11	10
Progress Energy | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	26	32
Duke Energy Progress
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	90	167
Trade and Other Receivables, not past due	357	398
Deferred Payment Arrangements	37	52
Trade and Other Receivables	525	655
Duke Energy Progress | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	31	25
Duke Energy Progress | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	6	4
Duke Energy Progress | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	4	9
Duke Energy Florida
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	93	116
Trade and Other Receivables, not past due	275	307
Deferred Payment Arrangements	16	28
Trade and Other Receivables	426	509
Duke Energy Florida | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	15	29
Duke Energy Florida | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	5	6
Duke Energy Florida | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	22	23
Duke Energy Ohio
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	4	2
Trade and Other Receivables, not past due	55	60
Deferred Payment Arrangements	4
Trade and Other Receivables	102	102
Duke Energy Ohio | CRC
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	55	87
Duke Energy Ohio | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	8	8
Duke Energy Ohio | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	3	2
Duke Energy Ohio | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	28	30
Duke Energy Indiana
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	16	16
Trade and Other Receivables, not past due	35	26
Trade and Other Receivables	66	58
Duke Energy Indiana | CRC
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	87	134
Duke Energy Indiana | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	3	3
Duke Energy Indiana | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	1	1
Duke Energy Indiana | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	11	12
Piedmont
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	44	86
Trade and Other Receivables, not past due	185	149
Deferred Payment Arrangements	8	7
Trade and Other Receivables	271	262
Piedmont | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	21	8
Piedmont | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	6	3
Piedmont | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	$ 7	$ 9