Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Examination [Line Items]
Unrecognized federal tax benefit					$ 762,000,000
Alternative minimum tax					370,000,000
Deferred income tax provision related to indefinite-lived intangible assets	7,000,000		15,000,000
State and international tax expense	3,000,000		8,000,000
American Taxpayer Relief Act of 2012 credit				22,000,000
Income tax provision (benefit)	340,000,000	0	353,000,000	(22,000,000)
AA [Member]
Income Tax Examination [Line Items]
Unrecognized federal tax benefit					647,000,000
Alternative minimum tax					467,000,000
Non-cash tax provision on sale of fuel hedging contracts	328,000,000		328,000,000
Deferred income tax provision related to indefinite-lived intangible assets	7,000,000		14,000,000
State and international tax expense	1,000,000		5,000,000
Income tax provision (benefit)	336,000,000	0	347,000,000	(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
Fuel Hedging Contract [Member]
Income Tax Examination [Line Items]
Non-cash tax provision on sale of fuel hedging contracts	330,000,000		330,000,000
Fuel Hedging Contract [Member] | AA [Member]
Income Tax Examination [Line Items]
Non-cash tax provision on sale of fuel hedging contracts	$ 328,000,000		$ 328,000,000