Taxation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Deferred tax assets, net	$ 318.8	$ 306.3
Deferred tax liabilities, net	1,523.5	1,529.5
Unremitted foreign earnings	1,060.0	1,017.0
Unrecognized tax benefits that would impact effective tax rate	50.5
Accrued interest and penalties	13.2	11.7	$ 3.2
Tax Year 2020
Tax Credit Carryforward [Line Items]
Accrued interest and penalties	1.7
Tax Year 2019
Tax Credit Carryforward [Line Items]
Accrued interest and penalties		8.5
Tax Year 2018
Tax Credit Carryforward [Line Items]
Accrued interest and penalties			$ 0.3
State
Tax Credit Carryforward [Line Items]
Tax loss carryforward subject to expiration	37.2	38.0
Deferred loss carrying not subject to expiration	$ 2.7
Canada
Tax Credit Carryforward [Line Items]
Dividends withholding tax rate (percent)	5.00%
Federal and Foreign Tax Authority
Tax Credit Carryforward [Line Items]
Tax loss carryforward subject to expiration	$ 8.6
Deferred loss carrying not subject to expiration	54.0
Tax loss carryforwards	62.6	$ 86.9
Maximum
Tax Credit Carryforward [Line Items]
Change in unrecognized tax benefits is reasonably possible, amount	16.0
Other assets
Tax Credit Carryforward [Line Items]
Deferred tax assets, net	$ 5.9