Revenue (Aging of Trade Receivables) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	$ 829	$ 843
Trade and Other Receivables, not past due	1,624
Trade and Other Receivables	2,904
30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	152
60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	90
90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	209
Duke Energy Carolinas
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	332	298
Trade and Other Receivables, not past due	470
Trade and Other Receivables	944
Duke Energy Carolinas | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	49
Duke Energy Carolinas | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	29
Duke Energy Carolinas | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	64
Progress Energy
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	274	217
Trade and Other Receivables, not past due	685
Trade and Other Receivables	1,102
Progress Energy | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	56
Progress Energy | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	34
Progress Energy | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	53
Duke Energy Progress
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	137	122
Trade and Other Receivables, not past due	336
Trade and Other Receivables	542
Duke Energy Progress | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	28
Duke Energy Progress | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	17
Duke Energy Progress | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	24
Duke Energy Florida
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	137	95
Trade and Other Receivables, not past due	344
Trade and Other Receivables	555
Duke Energy Florida | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	28
Duke Energy Florida | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	17
Duke Energy Florida | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	29
Duke Energy Ohio
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	1	1
Trade and Other Receivables, not past due	48
Trade and Other Receivables	88
Duke Energy Ohio | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	6
Duke Energy Ohio | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	4
Duke Energy Ohio | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	29
Duke Energy Indiana
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	7	16
Trade and Other Receivables, not past due	28
Trade and Other Receivables	47
Duke Energy Indiana | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	1
Duke Energy Indiana | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	1
Duke Energy Indiana | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	10
Piedmont Natural Gas
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	6	$ 78
Trade and Other Receivables, not past due	73
Trade and Other Receivables	108
Piedmont Natural Gas | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	6
Piedmont Natural Gas | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	5
Piedmont Natural Gas | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	$ 18