Income Taxes (Components of Income Tax Expense (Benefits)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current income tax expense (benefit)
Federal	$ (19)us-gaap_CurrentFederalTaxExpenseBenefit	$ 123us-gaap_CurrentFederalTaxExpenseBenefit	$ 267us-gaap_CurrentFederalTaxExpenseBenefit
State and other income tax	20	23	67
Total current income taxes	1us-gaap_CurrentIncomeTaxExpenseBenefit	146us-gaap_CurrentIncomeTaxExpenseBenefit	334us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred income tax expense (benefit)
Federal	251	68	(47)
State and other income tax	46	40	(5)
Total deferred income taxes	297us-gaap_DeferredIncomeTaxExpenseBenefit	108us-gaap_DeferredIncomeTaxExpenseBenefit	(52)us-gaap_DeferredIncomeTaxExpenseBenefit
Income tax expense	$ 298us-gaap_IncomeTaxExpenseBenefit	$ 254us-gaap_IncomeTaxExpenseBenefit	$ 282us-gaap_IncomeTaxExpenseBenefit

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.