Income Taxes - Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of variation of effective income tax rate from continuing operations from the statutory federal income tax rate
Income tax at the U.S. federal statutory rate		$ 83.2	$ 99.2	$ 85.7
Adjustments:
State and local income taxes, net of federal tax benefit		4.8	7.4	6.8
Tax on foreign remittances and U.S. tax on foreign income		22.5	26.4	21.1
Tax expense related to undistributed earnings of foreign subsidiaries		0.1	6.0	0.0
Foreign losses without current tax benefits		2.5	3.2	3.7
Foreign earnings taxed at different rates including tax holidays		11.1	12.6	11.1
U.S. foreign tax credit		(13.8)	(18.3)	(21.2)
Accruals and settlements related to tax audits		3.4	11.1	(3.8)
Valuation allowance changes		(0.7)	(44.5)	0.0
Deferred taxes related to branch operations	$ 5.3	0.0	5.3	0.0
U.S. Tax Reform		0.0	0.0	(10.6)
Other tax rate change		0.8	(5.0)	(2.4)
Other items, net		(10.0)	(5.7)	12.2
United States and foreign tax provision on income		$ 103.9	$ 97.7	$ 102.6
Effective income tax rate		26.20%	20.70%	25.10%