Restructuring Liability (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2020	Sep. 30, 2020
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2020	$ 31.9
Restructuring charges	41.8
Cash paid	(49.0)
Reclassification to held for sale	(6.2)
Foreign currency translation adjustments and other	(0.5)
Restructuring liability as of September 30, 2020	18.0
Current portion		$ 12.5
Noncurrent portion		5.5
Total	18.0	18.0
Employee severance and termination
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2020	19.1
Restructuring charges	32.3
Cash paid	(39.6)
Reclassification to held for sale	(2.8)
Foreign currency translation adjustments and other	0.4
Restructuring liability as of September 30, 2020	9.4
Current portion		9.4
Noncurrent portion		0.0
Total	9.4	9.4
Employee severance and termination \| Switzerland
Restructuring Reserve [Roll Forward]
Restructuring charges	12.7
Employee severance and termination \| U.K./Ireland
Restructuring Reserve [Roll Forward]
Restructuring charges	11.8
Office closures
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2020	2.2
Restructuring charges	3.1
Cash paid	(2.2)
Reclassification to held for sale	(3.4)
Foreign currency translation adjustments and other	0.3
Restructuring liability as of September 30, 2020	0.0
Current portion		0.0
Noncurrent portion		0.0
Total	0.0	0.0
Contract termination
Restructuring Reserve [Roll Forward]
Restructuring liability as of January 1, 2020	10.6
Restructuring charges	6.4
Cash paid	(7.2)
Reclassification to held for sale	0.0
Foreign currency translation adjustments and other	(1.2)
Restructuring liability as of September 30, 2020	8.6
Current portion		3.1
Noncurrent portion		5.5
Total	8.6	$ 8.6
Central and Corporate \| Employee severance and termination
Restructuring Reserve [Roll Forward]
Restructuring charges	$ 6.6

Amount of financing receivable reclassified to held-for-sale.

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Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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