Taxation - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 62.1	$ 69.9
Reductions for statute closings	9.3
Unrecognized tax benefits that, if recognized, would affect the effective tax rate	48.3
Minimum
Income Tax Contingency [Line Items]
Range of possible change in gross unrecognized tax benefits	6.0
Maximum
Income Tax Contingency [Line Items]
Range of possible change in gross unrecognized tax benefits	$ 12.0