Derivatives and Hedging (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Pretax deferred losses related to effective cash flow hedges	$ 59	$ 151
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	4
Undesignated commodity contracts latest expiration year	2018
Duke Energy Carolinas [Member]
Derivative [Line Items]
Pretax deferred losses related to effective cash flow hedges	23
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	5
Progress Energy [Member]
Derivative [Line Items]
Pretax deferred losses related to effective cash flow hedges	61	65
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	$ 5