Income Taxes (Components of deferred tax assets and liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Components Of Deferred Tax Assets And Liabilities [Line Items]
Reserves and allowances	$ 119	$ 78
Intangibles	0	45
Debt cancellation and other	37	0
Net operating loss and credit carryforwards	449	156
Deferred tax assets - current	265	104
Deferred tax assets - non-current	340	175
Total deferred tax assets	605	279
Property and equipment	(1,236)	(620)
Intangibles	(405)	(5)
Debt cancellation and other	0	(18)
Valuation allowance - current	0	0
Valuation allowance - non-current	(1)	(2)
Valuation allowance	1	2
Deferred tax liability - current	0	0
Deferred tax liability - non-current	(1,642)	(645)
Total deferred tax liability	1,642	645
Net deferred tax asset (liability) - current	265	104
Net deferred tax assets (liability) - non-current	(1,302)	(470)
Total deferred income tax asset (liability)	(1,037)	(366)
Current [Member]
Components Of Deferred Tax Assets And Liabilities [Line Items]
Reserves and allowances	61	45
Intangibles	0	0
Debt cancellation and other	0	0
Net operating loss and credit carryforwards	204	59
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	58	33
Intangibles	0	45
Debt cancellation and other	37	0
Net operating loss and credit carryforwards	245	97
Property and equipment	(1,236)	(620)
Intangibles	(405)	(5)
Debt cancellation and other	$ 0	$ (18)