Income Taxes (Narrative) (Details) (USD $)	3 Months Ended				12 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Income Tax Examination [Line Items]
Unrecognized federal tax benefit					$ 762,000,000
Alternative minimum tax					370,000,000
Income tax special items, net	8,000,000	[1]	0	[1]
Income tax provision (benefit)	13,000,000		(22,000,000)
American Taxpayer Relief Act of 2012 credit			22,000,000
AA [Member]
Income Tax Examination [Line Items]
Unrecognized federal tax benefit					647,000,000
Alternative minimum tax					467,000,000
Income tax special items, net	7,000,000	[1]	0	[1]
Income tax provision (benefit)	11,000,000		(30,000,000)
American Taxpayer Relief Act of 2012 credit			30,000,000
State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
NOL subject to expiration					4,700,000,000
Valuation allowance					415,000,000
State and Local Jurisdiction [Member] | AA [Member]
Income Tax Examination [Line Items]
NOL subject to expiration					3,800,000,000
Valuation allowance					378,000,000
Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
NOL subject to expiration					10,600,000,000
Valuation allowance					4,600,000,000
Internal Revenue Service (IRS) [Member] | AA [Member]
Income Tax Examination [Line Items]
NOL subject to expiration					9,500,000,000
Valuation allowance					4,900,000,000
Foreign Tax Authority and State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Income tax provision (benefit)	5,000,000
Foreign Tax Authority and State and Local Jurisdiction [Member] | AA [Member]
Income Tax Examination [Line Items]
Income tax provision (benefit)	$ 4,000,000

[1] The 2014 first quarter included a special $8 million non-cash deferred income tax provision related to certain indefinite-lived intangible assets.