Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Difference between income taxes computed at the U.S. federal statutory income tax rate and the income tax expense (benefit)
Federal income tax provision at statutory rate	$ 343	$ 462	$ 510
Statutory income tax rate (in percent)	35.00%	35.00%	35.00%
State taxes, net of federal benefit	5	6	31
State taxes, net of federal benefit (in percent)	0.00%	0.00%	2.00%
Research and development credits	(24)	(49)	(10)
Research and development credits (in percent)	(2.00%)	(4.00%)	(1.00%)
Domestic production activity deduction	0	(9)	(17)
Domestic production activity deduction (in percent)	0.00%	(1.00%)	(1.00%)
Foreign rate differential	(245)	(174)	(241)
Foreign rate differential (in percent)	(25.00%)	(13.00%)	(17.00%)
Change in tax reserves	128	89	53
Change in tax reserves (in percent)	13.00%	7.00%	4.00%
Shortfall from employee stock option exercises	0	0	8
Shortfall from employee stock option exercises (in percent)	0.00%	0.00%	0.00%
Return to provision adjustment	(7)	(3)	(4)
Return to provision adjustment (in percent)	(1.00%)	0.00%	0.00%
Net Operating Loss tax attribute received from Internal Revenue Service audit	0	0	(46)
Net Operating Loss tax attribute received from IRS audit (in percent)	0.00%	0.00%	(3.00%)
Net Operating Loss tax attribute received from Purchase Transaction	(52)	(16)	0
Net Operating Loss tax attribute received from Purchase Transaction (in percent)	(5.00%)	(1.00%)	0.00%
Other	(2)	3	25
Other (in percent)	0.00%	0.00%	2.00%
Income tax expense	$ 146	$ 309	$ 309
Total (in percent)	15.00%	23.00%	21.00%