Related Party Transactions (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013
Related Party Transaction [Line Items]
Debt instrument, face amount	$ 5,343	$ 4,023
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Intercompany loan receivable	382	222
Debt instrument, face amount	650
Progress Energy [Member]
Related Party Transaction [Line Items]
Intercompany loan receivable	0	75
Intercompany loan payable	455	1,213
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Intercompany loan payable	364	462
Debt instrument, face amount	1,000	800
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Intercompany loan receivable	207	0
Intercompany loan payable	0	181
Debt instrument, face amount	650
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Intercompany loan receivable	1	57
Transfer of Vermillion Generating Station	(28)
Intercompany loan payable	245	43
Debt instrument, face amount		450
Duke Energy Ohio [Member] | DECAM [Member]
Related Party Transaction [Line Items]
Intercompany loan payable	79	43
Duke Energy Ohio [Member] | Vermillion Generation Station [Member]
Related Party Transaction [Line Items]
Transfer of Vermillion Generating Station	28
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Intercompany loan receivable		96
Transfer of Vermillion Generating Station	26
Intercompany loan payable	81	0
Debt instrument, face amount	250	500
Duke Energy Indiana [Member] | Vermillion Generation Station [Member]
Related Party Transaction [Line Items]
Transfer of Vermillion Generating Station	$ 26