Income Taxes, Provision and Effective tax rate (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Taxes
Provision for income taxes	$ (99.3)	$ (91.8)	$ (213.3)	$ (250.0)
Effective tax rate (as a percent)	22.10%	24.50%	20.00%	22.90%
Discrete income tax benefit, tax on foreign income			$ 19.9
Discrete income tax benefit, impact on effective tax rate (in basis points)			(1.90%)
Excess tax benefit from option exercises	$ 10.7	$ 1.6	$ 28.1	$ 21.3
Excess tax benefit, impact on effective tax rate (in basis points)	(2.40%)	(0.40%)	(2.60%)	(1.90%)
Early extinguishment of debt, impact on effective tax rate (in basis points)		0.40%		0.10%