Income Taxes - Components of Income Tax (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of income before provision for income taxes and noncontrolling interest
Domestic									$ 296.2	$ 160.6	$ 474.2
Foreign									118.2	372.1	337.6
Income before income taxes	$ 174.0	$ 118.1	$ 77.8	$ 44.5	$ 188.4	$ 152.0	$ 150.9	$ 41.4	414.4	532.7	811.8
Current provision (benefit):
Federal									6.2	(126.1)	594.3
States									14.4	9.0	13.9
Foreign									48.5	38.9	45.4
Total current provision (benefit)									69.1	(78.2)	653.6
Deferred provision (benefit):
Federal									0.8	36.6	(128.7)
States									2.8	2.2	(17.7)
Foreign									(3.3)	5.2	(1.6)
Total deferred provision (benefit)									0.3	44.0	(148.0)
Income tax reconciliation
Expected provision at 35% rate									87.0	111.9	284.1
State taxes, net of federal benefit									9.4	7.4	12.0
Foreign income at different tax rates									1.8	(12.8)	(46.4)
R&D tax credits									(18.8)	(22.1)	(15.1)
Share-based compensation									3.8	4.7	0.0
Non-deductible compensation									3.3	1.9	1.6
Temporary differences not currently benefited									12.9	0.0	0.0
Recognition of previously unrecognized tax benefits									25.4		0.0
Lapses in federal statutes of limitations									7.5	67.6	0.0
Tax accounting method changes									0.0	(65.4)	0.0
Release of valuation allowance									0.0	0.0	(1.7)
Domestic production activities									0.0	0.0	(12.4)
Impact of the U.S. Tax Cuts and Jobs Act									0.0	2.8	289.5
Other									2.9	5.0	(6.0)
Total provision (benefit) for income taxes									$ 69.4	(34.2)	$ 505.6
Product
Income tax reconciliation
Income tax benefit result of filing a change in accounting method										(33.2)
Service
Income tax reconciliation
Income tax benefit result of filing a change in accounting method										$ (33.2)