Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Tax exempt bonds	$ (1,053)	$ (1,296)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	7,500
Commercial Paper	(3,138)
Outstanding letters of credit	(72)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	3,674
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	3,475
Commercial Paper	(1,531)
Outstanding letters of credit	(65)
Available capacity	1,879
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Commercial Paper	625
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(355)	(355)
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance required	250
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	800
Commercial Paper	(300)
Outstanding letters of credit	(4)
Tax exempt bonds	(35)
Coal ash set-aside	(250)
Available capacity	211
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance required	250
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(48)	(291)
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance required	250
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,000
Commercial Paper	(333)
Outstanding letters of credit	(2)
Coal ash set-aside	(250)
Available capacity	415
Duke Energy Progress [Member] | Revolving Credit Facility [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance required	250
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,200
Commercial Paper	(709)
Outstanding letters of credit	(1)
Available capacity	490
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	425
Commercial Paper	(115)
Available capacity	310
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(572)	$ (573)
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