Summary of Significant Accounting Policies (Narrative)(Details) (USD $)	12 Months Ended		1 Months Ended	12 Months Ended	96 Months Ended	6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2022	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2011	Mar. 01, 2013
Organization And Basis Of Presentation [Line Items]
SAFSTOR Commencement Period	60 years
Preferred Stock Of Subsidiaries [Abstract]
Payments for the redemption of preferred stock		$ 96,000,000
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	2,036,000,000	1,501,000,000		1,424,000,000			2,036,000,000	2,110,000,000
Restricted Cash [Abstract]
Restricted cash	298,000,000	307,000,000					298,000,000
Duke Energy Carolinas [Member]
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	13,000,000	23,000,000		19,000,000			13,000,000	289,000,000
Progress Energy [Member]
Preferred Stock Of Subsidiaries [Abstract]
Payments for the redemption of preferred stock		96,000,000
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	42,000,000	58,000,000		231,000,000			42,000,000	230,000,000
Duke Energy Progress [Member]
Preferred Stock Of Subsidiaries [Abstract]
Payments for the redemption of preferred stock		62,000,000	62,000,000	0
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	9,000,000	21,000,000		18,000,000			9,000,000	20,000,000
Duke Energy Progress [Member] | Minimum [Member]
Preferred Stock Of Subsidiaries [Abstract]
Redemption price									$ 101.00
Duke Energy Progress [Member] | Maximum [Member]
Preferred Stock Of Subsidiaries [Abstract]
Redemption price									$ 110.00
Duke Energy Florida [Member]
Preferred Stock Of Subsidiaries [Abstract]
Payments for the redemption of preferred stock		34,000,000	34,000,000
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	8,000,000	16,000,000		131,000,000			8,000,000	16,000,000
Duke Energy Florida [Member] | Minimum [Member]
Preferred Stock Of Subsidiaries [Abstract]
Redemption price									$ 101.00
Duke Energy Florida [Member] | Maximum [Member]
Preferred Stock Of Subsidiaries [Abstract]
Redemption price									$ 104.25
Duke Energy Ohio [Member]
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	20,000,000	36,000,000		31,000,000			20,000,000	99,000,000
Duke Energy Indiana [Member]
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	6,000,000	15,000,000		36,000,000			6,000,000	16,000,000
International Energy [Member]
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents at end of period	1,680,000,000						1,680,000,000
Restricted Cash [Abstract]
Cash Repatriation period	8 years
International Energy [Member] | Scenario, Forecast [Member]
Cash and Cash Equivalents [Abstract]
Foreign Earnings Repatriated					$ 2,700,000,000
Utility Franchise Tax Member [Member] | Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate						3.22%
Utility Franchise Tax Member [Member] | Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate						3.22%
Electricity Sales Tax Member [Member] | Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate						3.00%
Electricity Sales Tax Member [Member] | Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate						3.00%
Current [Member] | Electricity Sales Tax Member [Member] | Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate							7.00%
Current [Member] | Electricity Sales Tax Member [Member] | Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate							7.00%