Derivatives and Hedging (Cash Flow Hedges - Location and Amount of PreTax Recognized in Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	$ (406)		$ (367)
Designated As Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total pretax gains (losses) recorded in AOCI	2		14
Pretax gains and (losses) recognized in earnings on derivatives	(1)	[1],[2]	(1)	[1],[2]
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recorded in AOCI - interest rate contracts	2		13
Interest expense	(1)	[2],[3]	(1)	[1],[2]
Designated As Hedging Instrument [Member] | Commodity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recorded in AOCI - commodity contracts			1
Duke Energy Carolinas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	(101)		(82)
Progress Energy [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	(169)		(198)
Duke Energy Progress [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	(57)		(48)
Duke Energy Florida [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	(49)		(49)
Duke Energy Ohio [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	(22)		(18)
Duke Energy Indiana [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	$ (43)		$ (41)

[1] Represents the gains and losses on cash flow hedges previously recorded in AOCI during the term of the hedging relationship and reclassified into earnings during the current period.

[2] Amounts in AOCI related to terminated hedges are reclassified to earnings as the interest expense is recorded. The effective portion of the hedges will be amortized to interest expense over the term of the related debt.

[3] Represents the gains and losses on cash flow hedges previously recorded in AOCI during the term of the hedging relationships and reclassified into earnings during the current period.