Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2017	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	$ 51.7	$ 113.3
Tax credit carryforward		68.2
Disallowed interest carryforward	40.2	5.4
Provisional income tax benefit			$ 196.8
Final income tax benefit			$ 186.3
Unrecognized tax benefits that would favorably impact effective tax rate	47.4	42.3		$ 36.0
Accrued interest and penalties	2.1	2.4		$ 0.0
Income tax impact related to tax court decision		1.0
U.S.
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards		383.1
Operating loss carryforward, subject to expiration		140.8
Operating loss carryforward, not subject to expiration		242.3
Disallowed interest carryforward		6.7
Foreign
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards		117.2
Operating loss carryforward, subject to expiration		7.8
Operating loss carryforward, not subject to expiration		$ 109.4
Foreign | Swiss Federal Tax Administration (FTA)
Tax Credit Carryforward [Line Items]
Income tax expense, remeasurement of deferred tax assets	$ 4.4
Foreign | Maximum
Tax Credit Carryforward [Line Items]
Carryforward period		20 years
Foreign | Minimum
Tax Credit Carryforward [Line Items]
Carryforward period		5 years