Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Tax-exempt bonds	$ (730,000,000)	$ (941,000,000)
Duke Energy Carolinas
Line of Credit Facility [Line Items]
Tax-exempt bonds	(243,000,000)	(243,000,000)
Duke Energy Progress
Line of Credit Facility [Line Items]
Tax-exempt bonds	(48,000,000)	(48,000,000)
Duke Energy Ohio
Line of Credit Facility [Line Items]
Tax-exempt bonds	(77,000,000)	(77,000,000)
Duke Energy Indiana
Line of Credit Facility [Line Items]
Tax-exempt bonds	(362,000,000)	$ (572,000,000)
Revolving Credit Facility
Line of Credit Facility [Line Items]
Facility Size	8,000,000,000
Commercial Paper	(2,537,000,000)
Outstanding letters of credit	(50,000,000)
Tax-exempt bonds	(81,000,000)
Coal ash set-aside	(500,000,000)
Available capacity	4,832,000,000
Revolving Credit Facility | Parent Company
Line of Credit Facility [Line Items]
Facility Size	2,650,000,000
Commercial Paper	(1,119,000,000)
Outstanding letters of credit	(42,000,000)
Available capacity	1,489,000,000
Revolving Credit Facility | Duke Energy Carolinas
Line of Credit Facility [Line Items]
Facility Size	1,500,000,000
Commercial Paper	(325,000,000)
Outstanding letters of credit	(4,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	921,000,000
Revolving Credit Facility | Duke Energy Progress
Line of Credit Facility [Line Items]
Facility Size	1,250,000,000
Commercial Paper	(207,000,000)
Outstanding letters of credit	(2,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	791,000,000
Revolving Credit Facility | Duke Energy Florida
Line of Credit Facility [Line Items]
Facility Size	800,000,000
Available capacity	800,000,000
Revolving Credit Facility | Duke Energy Ohio
Line of Credit Facility [Line Items]
Facility Size	600,000,000
Commercial Paper	(296,000,000)
Available capacity	304,000,000
Revolving Credit Facility | Duke Energy Indiana
Line of Credit Facility [Line Items]
Facility Size	600,000,000
Commercial Paper	(176,000,000)
Tax-exempt bonds	(81,000,000)
Available capacity	343,000,000
Revolving Credit Facility | Piedmont
Line of Credit Facility [Line Items]
Facility Size	600,000,000
Commercial Paper	(414,000,000)
Outstanding letters of credit	(2,000,000)
Available capacity	184,000,000
Proceeds Loaned To Subsidiary Registrants | Revolving Credit Facility | Parent Company
Line of Credit Facility [Line Items]
Commercial Paper	$ (625,000,000)