Revenue (Aging of Trade Receivables) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	$ 894	$ 969
Trade and Other Receivables, not past due	1,836	1,789
Deferred Payment Arrangements	106	215
Trade and Other Receivables	3,211	3,299
30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	148	185
60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	47	22
90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	180	119
Duke Energy Carolinas
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	324	328
Trade and Other Receivables, not past due	465	445
Deferred Payment Arrangements	46	96
Trade and Other Receivables	991	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	20	1
Duke Energy Carolinas | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	74	16
Progress Energy
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	283	283
Trade and Other Receivables, not past due	781	707
Deferred Payment Arrangements	35	80
Trade and Other Receivables	1,182	1,166
Progress Energy | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	42	54
Progress Energy | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	10	10
Progress Energy | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	31	32
Duke Energy Progress
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	156	167
Trade and Other Receivables, not past due	408	398
Deferred Payment Arrangements	24	52
Trade and Other Receivables	623	655
Duke Energy Progress | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	22	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	7	9
Duke Energy Florida
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	127	116
Trade and Other Receivables, not past due	372	307
Deferred Payment Arrangements	11	28
Trade and Other Receivables	558	509
Duke Energy Florida | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	20	29
Duke Energy Florida | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	4	6
Duke Energy Florida | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	24	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	2
Trade and Other Receivables	100	102
Duke Energy Ohio | CRC
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	66	87
Duke Energy Ohio | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	4	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	32	30
Duke Energy Indiana
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	30	16
Trade and Other Receivables, not past due	29	26
Trade and Other Receivables	72	58
Duke Energy Indiana | CRC
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	114	134
Duke Energy Indiana | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	2	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	10	12
Piedmont
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	5	86
Trade and Other Receivables, not past due	82	149
Deferred Payment Arrangements	7	7
Trade and Other Receivables	119	262
Piedmont | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	8	8
Piedmont | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	5	3
Piedmont | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	$ 12	$ 9