Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Tax exempt bonds	$ (1,053)	$ (1,053)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	8,350
Commercial Paper	(2,022)
Outstanding letters of credit	(78)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	5,634
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	3,400
Commercial Paper	(977)
Outstanding letters of credit	(69)
Available capacity	2,354
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(355)	(355)
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	1,100
Commercial Paper	(300)
Outstanding letters of credit	(4)
Tax exempt bonds	(35)
Coal ash set-aside	(250)
Available capacity	511
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	850
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(48)	(48)
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	1,000
Commercial Paper	(150)
Outstanding letters of credit	(2)
Coal ash set-aside	(250)
Available capacity	598
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	950
Commercial Paper	(84)
Outstanding letters of credit	(1)
Available capacity	865
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(77)	(77)
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	450
Commercial Paper	(31)
Available capacity	419
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(572)	$ (572)
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	600
Commercial Paper	(150)
Tax exempt bonds	(81)
Available capacity	369
Proceeds Loaned To Subsidiary Registrants [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Commercial Paper	$ (625)