Taxation (Schedule of Deferred Tax Recognized on Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Compensation and benefits	$ 125.9	$ 179.6
Lease obligations	44.5	65.9
Tax loss carryforwards	99.8	124.9
Investments	39.0	32.7
Accrued liabilities	97.7	4.1
Other	16.4	25.5
Total deferred tax assets	423.3	432.7
Valuation allowance	(104.5)	(126.4)
Deferred tax assets, net of valuation allowance	318.8	306.3
Deferred tax liabilities:
Goodwill and intangibles	(1,745.4)	(1,710.4)
Leased assets	(40.3)	(62.5)
Fixed assets	(27.8)	(40.0)
Other	(22.9)	(20.6)
Total deferred tax liabilities	(1,836.4)	(1,833.5)
Net deferred tax liability	$ (1,517.6)	$ (1,527.2)