Income Taxes, Deferred Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carry-forwards	$ 1.0	$ 1.3
Foreign tax credit carry-forwards	75.4	69.7
Research and other credit carry-forwards	128.7	122.5
Deferred revenue	109.3	104.9
Stock-based compensation	49.1	55.8
Cost sharing adjustment	70.1	0.0
Reserves and accruals not currently deductible	173.9	129.8
Other	19.2	19.8
Total deferred tax assets	626.7	503.8
Valuation allowance	(146.2)	(144.5)
Deferred tax assets, net of valuation allowance	480.5	359.3
Deferred tax liabilities:
Property and equipment basis differences	(44.1)	(35.6)
Purchased intangibles	(3.1)	(16.7)
Unremitted foreign earnings	(365.4)	(260.6)
Deferred compensation and other	(12.0)	(5.1)
Other	0.0	0.0
Total deferred tax liabilities	(424.6)	(318.0)
Net deferred tax assets	55.9	41.3
Valuation allowance	146.2	144.5
Increase (decrease) in DTA valuation allowance	1.7	$ (11.2)
Cumulative undistributed earnings of certain foreign subsidiaries	2,200.0
California [Member]
Deferred tax liabilities:
Net operating loss carry-forwards	49.5
Tax credit carry-forwards	237.1
Tax credit carry-forward to be credited to APIC when realized	19.5
California Deferred Tax Assets [Member]
Deferred tax assets:
Valuation allowance	(128.1)
Deferred tax liabilities:
Valuation allowance	128.1
Net operating loss carry-forwards	48.0
Massachusetts Deferred Tax Assets [Member]
Deferred tax assets:
Valuation allowance	(9.7)
Deferred tax liabilities:
Valuation allowance	9.7
Capital Loss Carryforward [Member]
Deferred tax assets:
Valuation allowance	(8.4)
Deferred tax liabilities:
Valuation allowance	$ 8.4