Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Effective tax rate (as a percent)	25.00%		26.00%	23.00%	24.00%
Statutory tax rate (as a percent)				35.00%
Reasonably possible amount that gross unrecognized tax benefits may change within the next twelve months, high end of range	$ 22			$ 22
Pharmacyclics Inc
Reversal of previously recognized state valuation allowances		$ 103