Income Taxes (Components of deferred tax assets and liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Components Of Deferred Tax Assets And Liabilities [Line Items]
Reserves and allowances	$ 78	$ 78
Intangibles	45	81
Net operating loss and credit carryforwards	156	167
Deferred tax assets - current	104	69
Deferred tax assets - non-current	175	257
Deferred tax assets	279	326
Property and equipment	(620)	(618)
Intangibles	(5)	0
Debt cancellation and other	(18)	(22)
Valuation allowance - current	0	0
Valuation allowance - non-current	(2)	(2)
Valuation allowance	(2)	(2)
Deferred tax liability - current	0	0
Deferred tax liability - non-current	(645)	(642)
Deferred tax liability	(645)	(642)
Net deferred tax asset (liability) - current	104	69
Net deferred tax assets (liability) - non-current	(470)	(385)
Net deferred tax asset (liability)	(366)	(316)
Current [Member]
Components Of Deferred Tax Assets And Liabilities [Line Items]
Reserves and allowances	45	69
Intangibles	0	0
Net operating loss and credit carryforwards	59	0
Property and equipment	0	0
Intangibles	0	0
Debt cancellation and other	0	0
Non-Current [Member]
Components Of Deferred Tax Assets And Liabilities [Line Items]
Reserves and allowances	33	9
Intangibles	45	81
Net operating loss and credit carryforwards	97	167
Property and equipment	(620)	(618)
Intangibles	(5)	0
Debt cancellation and other	$ (18)	$ (22)