Income Taxes (Components of Income Tax Expense (Benefits)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal income tax expense (benefit)	$ 123	$ 267	$ 15
State and other income tax expense (benefit)	23	67	21
Total current income tax expense (benefit)	146	334	36
Federal deferred income tax expense (benefit)	68	(47)	193
State and other income tax deferred expense (benefit)	40	(5)	38
Total deferred income tax expense (benefit)	108	(52)	231
Income Tax Expense (Benefit)	$ 254	$ 282	$ 267