Revenue (Aging of Trade Receivables) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	$ 716	$ 843
Trade and Other Receivables, not past due	1,584
Trade and Other Receivables	2,726
30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	216
60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	65
90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	145
Duke Energy Carolinas
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	285	298
Trade and Other Receivables, not past due	448
Trade and Other Receivables	839
Duke Energy Carolinas | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	69
Duke Energy Carolinas | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	18
Duke Energy Carolinas | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	19
Progress Energy
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	195	217
Trade and Other Receivables, not past due	585
Trade and Other Receivables	924
Progress Energy | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	67
Progress Energy | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	20
Progress Energy | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	57
Duke Energy Progress
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	85	122
Trade and Other Receivables, not past due	321
Trade and Other Receivables	496
Duke Energy Progress | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	44
Duke Energy Progress | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	14
Duke Energy Progress | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	32
Duke Energy Florida
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	110	95
Trade and Other Receivables, not past due	262
Trade and Other Receivables	426
Duke Energy Florida | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	23
Duke Energy Florida | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	6
Duke Energy Florida | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	25
Duke Energy Ohio
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	1	1
Trade and Other Receivables, not past due	45
Trade and Other Receivables	89
Duke Energy Ohio | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	9
Duke Energy Ohio | 60-90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	2
Duke Energy Ohio | 90 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	32
Duke Energy Indiana
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	16	16
Trade and Other Receivables, not past due	24
Trade and Other Receivables	53
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	11
Piedmont Natural Gas
Financing Receivable, Past Due [Line Items]
Unbilled Receivables	32	$ 78
Trade and Other Receivables, not past due	134
Trade and Other Receivables	200
Piedmont Natural Gas | 30-60 days
Financing Receivable, Past Due [Line Items]
Trade and Other Receivables	18
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	$ 11