Fair Value Of Financial Assets and Liabilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Auction Rate Securities [Abstract]
Settlements	$ (10)	$ (54)	$ (3)	$ (63)
Interest Rate Current [Member]
Auction Rate Securities [Abstract]
Level 3 ARS assumptions	0.20%		0.20%
Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Risk Adjusted Discount Rates [Member]
Auction Rate Securities [Abstract]
Level 3 ARS assumptions	5.80%		5.80%
Duke Energy Carolinas [Member]
Auction Rate Securities [Abstract]
Settlements	$ 1	$ (8)	$ 8	$ (8)