Revenue (Aging of Trade Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Unbilled receivables	$ 969	$ 843
Not past due	1,789
Deferred Payment Arrangements	215
Trade and Other Receivables	3,299
30-60 days
Financing Receivable, Past Due [Line Items]
Past due	185
60-90 days
Financing Receivable, Past Due [Line Items]
Past due	22
90+ days
Financing Receivable, Past Due [Line Items]
Past due	119
Duke Energy Carolinas
Financing Receivable, Past Due [Line Items]
Unbilled receivables	328	298
Not past due	445
Deferred Payment Arrangements	96
Trade and Other Receivables	966
Duke Energy Carolinas | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	80
Duke Energy Carolinas | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	1
Duke Energy Carolinas | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	16
Progress Energy
Financing Receivable, Past Due [Line Items]
Unbilled receivables	283	217
Not past due	707
Deferred Payment Arrangements	80
Trade and Other Receivables	1,166
Progress Energy | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	54
Progress Energy | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	10
Progress Energy | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	32
Duke Energy Progress
Financing Receivable, Past Due [Line Items]
Unbilled receivables	167	122
Not past due	398
Deferred Payment Arrangements	52
Trade and Other Receivables	655
Duke Energy Progress | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	25
Duke Energy Progress | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	4
Duke Energy Progress | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	9
Duke Energy Florida
Financing Receivable, Past Due [Line Items]
Unbilled receivables	116	95
Not past due	307
Deferred Payment Arrangements	28
Trade and Other Receivables	509
Duke Energy Florida | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	29
Duke Energy Florida | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	6
Duke Energy Florida | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	23
Duke Energy Ohio
Financing Receivable, Past Due [Line Items]
Unbilled receivables	2	1
Not past due	60
Trade and Other Receivables	102
Duke Energy Ohio | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	8
Duke Energy Ohio | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	2
Duke Energy Ohio | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	30
Duke Energy Indiana
Financing Receivable, Past Due [Line Items]
Unbilled receivables	16	16
Not past due	26
Trade and Other Receivables	58
Duke Energy Indiana | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	3
Duke Energy Indiana | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	1
Duke Energy Indiana | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	12
Piedmont
Financing Receivable, Past Due [Line Items]
Unbilled receivables	86	$ 78
Not past due	149
Deferred Payment Arrangements	7
Trade and Other Receivables	262
Piedmont | 30-60 days
Financing Receivable, Past Due [Line Items]
Past due	8
Piedmont | 60-90 days
Financing Receivable, Past Due [Line Items]
Past due	3
Piedmont | 90+ days
Financing Receivable, Past Due [Line Items]
Past due	$ 9