Derivatives and Hedge Accounting Activities (Selected Information Related to Gains (Losses) on Cash Flow Hedges Included in AOCI) (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Commodity Gas	Dec. 31, 2013 Commodity Electricity	Dec. 31, 2013 Commodity Other	Dec. 31, 2013 Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (288)	$ (122)	$ (3)	$ (172)	$ (3)	$ (110)
Amounts Expected to be Reclassified to Earnings during the next 12 Months After-Tax	$ (137)		$ (3)	$ (124)	$ (3)	$ (7)
Maximum Term			28 months	36 months	29 months	364 months