Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Facility size	$ 6,000,000,000
Tax exempt bonds	(1,296,000,000)	(2,356,000,000)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	6,000,000,000
Long-term Commercial Paper	(2,021,000,000)
Outstanding letters of credit	(70,000,000)
Tax exempt bonds	(116,000,000)
Available capacity	3,793,000,000
Proceeds Loaned To Subsidiary Registrants [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Long-term Commercial Paper	(475,000,000)
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(355,000,000)	(395,000,000)
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,000,000,000
Long-term Commercial Paper	(300,000,000)
Outstanding letters of credit	(4,000,000)
Tax exempt bonds	(35,000,000)
Available capacity	661,000,000
Progress Energy [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(291,000,000)	(910,000,000)
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(291,000,000)	(669,000,000)
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750,000,000
Outstanding letters of credit	(2,000,000)
Available capacity	748,000,000
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds		(241,000,000)
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	650,000,000
Long-term Commercial Paper	(29,000,000)
Outstanding letters of credit	(1,000,000)
Available capacity	620,000,000
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(77,000,000)	(479,000,000)
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	650,000,000
Long-term Commercial Paper	(38,000,000)
Available capacity	612,000,000
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(573,000,000)	(573,000,000)
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	700,000,000
Long-term Commercial Paper	(175,000,000)
Outstanding letters of credit	(1,000,000)
Tax exempt bonds	(81,000,000)
Available capacity	443,000,000
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	2,250,000,000
Long-term Commercial Paper	(1,479,000,000)
Outstanding letters of credit	(62,000,000)
Available capacity	$ 709,000,000