Income Taxes - Deferred Tax Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Net operating loss carryforward	$ 10	$ 3
Tax credit carryforward	37	9
Share-based compensation	233	79
Accrued expenses and other liabilities	83	58
Other	16	0
Total deferred tax assets	379	149
Less: valuation allowance	(37)	(9)
Deferred tax assets, net of valuation allowance	342	140
Deferred tax liabilities:
Depreciation and amortization	(97)	(69)
Purchased intangible assets	(92)	(10)
Deferred foreign taxes	(15)	(1)
Total deferred tax liabilities	(204)	(80)
Net deferred tax assets	$ 138	$ 60