Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Beginning Balance	$ 2,225.2	$ 1,954.8
Stated capital	40.7	53.1	$ 40.7	$ 53.1
Additional Paid in Capital, Common Stock	761.3	920.1	740.7	937.6
Retained Earnings (Accumulated Deficit)	1,429.0	1,964.8	1,339.5	1,907.4
Accumulated Other Comprehensive Income (Loss), Net of Tax	(2.1)	(118.9)	41.3	(50.1)
Treasury Stock, Value	(53.4)	(1,001.7)	(9.3)	(979.8)
Stockholders' Equity Attributable to Noncontrolling Interest	74.6	82.9	72.3	86.6
Stockholders' Equity Roll Forward
Net Income	116.0	84.0
Foreign currency translation adjustment	(44.4)	(78.8)
Pension and postretirement liability adjustments	(1.6)	(1.3)
Change in fair value of marketable securities		(0.4)
Change in fair value of derivative financial instruments, net of reclassifications	2.2	4.2
Change in ownership of noncontrolling interest		0.5
Dividends	$ (23.8)	$ (22.9)
Dividend per share	$ 0.29	$ 0.28
Stock-based compensation expense	$ 6.5	$ 5.6
Stock purchased at fair market value	(26.3)	(42.3)
Stock option exercise activity	14.1	7.5
Restricted shares surrendered (issued)		0.0
Payment, Tax Withholding, Share-based Payment Arrangement	(17.8)	(10.2)
Ending Balance	2,250.1	1,900.3
Income tax (expense) benefit	(0.3)	(1.0)
Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Roll Forward
Ending Balance		(0.4)
Other Paid-In Capital
Stockholders' Equity Roll Forward
Stock-based compensation expense	6.5	5.6
Stock option exercise activity	14.1	0.9
Restricted shares surrendered (issued)		(22.2)
Retained Earnings
Stockholders' Equity Roll Forward
Net Income	113.3	80.7
Dividends	(23.8)	(22.9)
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Roll Forward
Ending Balance		(0.4)
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity Roll Forward
Foreign currency translation adjustment	(44.0)	(71.3)
Pension and postretirement liability adjustments	(1.6)	(1.3)
Change in fair value of marketable securities		(0.4)
Change in fair value of derivative financial instruments, net of reclassifications	2.2	4.2
Treasury Stock
Stockholders' Equity Roll Forward
Stock purchased at fair market value	26.3	42.3
Stock option exercise activity		8.4
Restricted shares surrendered (issued)		22.2
Payment, Tax Withholding, Share-based Payment Arrangement	(17.8)	(10.2)
Non controlling Interest
Stockholders' Equity Roll Forward
Net Income	2.7	3.3
Foreign currency translation adjustment	(0.4)	(7.5)
Change in ownership of noncontrolling interest		0.5
Pension and other postretirement liability adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax	61.8	65.6	$ 63.4	$ 66.9
Stockholders' Equity Roll Forward
Income tax (expense) benefit	$ 0.6	0.5
Accounting Standards Update 2016-13
Stockholders' Equity Roll Forward
Cumulative effect of change in accounting		$ 0.2