Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tax Credit Carryforward [Line Items]
Change in estimate related to restructuring transactions			$ 30.5
Deferred tax assets, tax credit carryforwards, excluding adoption of ASU 2013-11	$ 120.3
Tax credit carryforward, valuation allowance	120.3
Foreign tax credit carryforwards	87.6
Tax credit carryforwards, research	24.8
Tax credit carryforward	7.9
Deferred tax assets, net operating loss	432.2
Operating loss carryforwards subject to offset in accordance with ASU 2013--11	77.5
Tax loss and deduction carryforwards	478.5	$ 425.0
Valuation allowance	941.4	815.4
Undistributed earnings of foreign subsidiaries	1,200.0
Decrease in deferred tax liability associated with undistributed earnings of foreign subsidiaries	10.2
Potential offset to valuation allowance	52.1
Total gross unrecognized tax benefits	249.8	251.7	372.1	$ 331.7
Unrecognized tax benefits that would impact effective tax rate	14.1
Expense (reversal of expense) for interest and penalties	0.2	0.5	1.0
Accrued interest and penalties	6.3	7.1
Increase in unrecognized tax benefits is reasonably possible	0.8
Minimum
Tax Credit Carryforward [Line Items]
Increase in unrecognized tax benefits is reasonably possible	85.0
Maximum
Tax Credit Carryforward [Line Items]
Increase in unrecognized tax benefits is reasonably possible	90.0
United Kingdom Tax Authority
Tax Credit Carryforward [Line Items]
Foreign income tax benefit		89.1	21.0
Foreign
Tax Credit Carryforward [Line Items]
Tax loss and deduction carryforwards	18.0
Valuation allowance	414.2
Operating loss carryforwards	2,480.8
Deferred tax asset, not subject to expiration	924.9
Deferred tax assets, operating loss carryforwards, subject to expiration	1,555.9
Domestic
Tax Credit Carryforward [Line Items]
Tax loss and deduction carryforwards	46.3
Deferred tax asset, not subject to expiration	220.4
Deferred Tax Assets That Cannot Be Benefitted
Tax Credit Carryforward [Line Items]
Net increase (decrease) in valuation allowance	141.4	163.7	65.1
Deferred Tax Assets Generated In Current Year
Tax Credit Carryforward [Line Items]
Net increase (decrease) in valuation allowance	115.0	70.9	69.9
Deferred Tax Assets, Change In Judgment
Tax Credit Carryforward [Line Items]
Net increase (decrease) in valuation allowance	26.4	3.7	4.7
Deferred Tax Asset, Tax On Foreign Income
Tax Credit Carryforward [Line Items]
Net increase (decrease) in valuation allowance		$ 89.1	21.0
Deferred Tax Assets, True-up Adjustment
Tax Credit Carryforward [Line Items]
Net increase (decrease) in valuation allowance			$ (30.5)
Valuation Allowance, Federal Loss Carryforwards | Domestic
Tax Credit Carryforward [Line Items]
Valuation allowance	$ 46.3