Income Taxes - Deferred Tax Assets (Liabilities) (Details) (USD $)			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 U.S. Internal Revenue Service (IRS)
Deferred Tax Assets:
Accrued payroll and related benefits	$ 119,000,000	$ 101,000,000
Deferred revenue	271,000,000	276,000,000
Unutilized tax net operating loss carry forwards	4,611,000,000	3,996,000,000
Fixed assets and intangible assets	134,000,000	157,000,000
Intercompany loss	148,000,000	164,000,000
Other	162,000,000	193,000,000
Total Deferred Tax Assets	5,445,000,000	4,887,000,000
Deferred Tax Liabilities:
Fixed assets and intangible assets	(702,000,000)	(542,000,000)
Deferred revenue	(87,000,000)	(93,000,000)
Other	(45,000,000)	(51,000,000)
Foreign branch income	(37,000,000)	(40,000,000)
Total Deferred Tax Liabilities	(871,000,000)	(726,000,000)
Net Deferred Tax Assets before valuation allowance	4,574,000,000	4,161,000,000
Valuation Allowance	(4,697,000,000)	(4,252,000,000)
Net Deferred Tax (Liability) Asset after Valuation Allowance	123,000,000	91,000,000
Net current deferred income tax asset	9,000,000	12,000,000
Net current deferred income tax liability	(3,000,000)	(3,000,000)
Net non-current deferred income tax asset	219,000,000	246,000,000
Net non-current deferred income tax liability	(348,000,000)	(346,000,000)
Operating Loss Carryforwards, increase			1,000,000,000
Internal Revenue Code 382, Cumulative Ownership Shift Benchmark			50.00%
Internal Revenue Code 382, Cumulative Ownership Shift Period Change			5.00%
Operating Loss Carryforwards			$ 8,526,000,000