Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Beginning Balance	$ 2,250.1	$ 1,900.3	$ 2,225.2	$ 1,954.8
Stated capital	40.7	53.1	40.7	53.1	$ 40.7	$ 40.7	$ 53.1	$ 53.1
Additional Paid in Capital, Common Stock	778.6	924.4	778.6	924.4	761.3	740.7	920.1	937.6
Retained Earnings (Accumulated Deficit)	1,510.9	2,005.7	1,510.9	2,005.7	1,429.0	1,339.5	1,964.8	1,907.4
Accumulated Other Comprehensive Income (Loss), Net of Tax	19.8	(99.2)	19.8	(99.2)	(2.1)	41.3	(118.9)	(50.1)
Treasury Stock, Value	(59.1)	(1,000.4)	(59.1)	(1,000.4)	(53.4)	(9.3)	(1,001.7)	(979.8)
Stockholders' Equity Attributable to Noncontrolling Interest	76.4	84.0	76.4	84.0	74.6	72.3	82.9	86.6
Stockholders' Equity Roll Forward
Net Income	107.2	61.8	223.2	145.8
Foreign currency translation adjustment	23.2	24.5	(21.2)	(54.3)
Pension and postretirement liability adjustments	(1.7)	(1.5)	(3.3)	(2.8)
Change in fair value of marketable securities		0.5		0.1
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(0.2)	(2.6)	2.0	1.6
Dividends	$ (22.9)	$ (21.0)	$ (46.7)	$ (43.9)
Dividend per share	$ 0.30	$ 0.28	$ 0.59	$ 0.56
Stock-based compensation expense	$ 6.0	$ 5.8	$ 12.5	$ 11.4
Purchase of treasury shares			(26.3)	(42.3)
Stock option exercise activity	11.3		25.4	7.5
Restricted shares surrendered (issued)		0.0		0.0
Payment, Tax Withholding, Share-based Payment Arrangement	(5.7)	(0.2)	(23.5)	(10.4)
Ending Balance	2,367.3	1,967.6	2,367.3	1,967.6
Income tax benefit	0.7	1.2	0.4	0.2
Other Comprehensive Income (Loss), Net of Tax, Change in Noncontrolling Interest				(0.5)
Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Roll Forward
Ending Balance		(0.4)		(0.4)
Other Paid-In Capital
Stockholders' Equity Roll Forward
Stock-based compensation expense	6.0	5.8	12.5	11.4
Stock option exercise activity	11.3		25.4	0.9
Restricted shares surrendered (issued)		(1.5)		(23.7)
Retained Earnings
Stockholders' Equity Roll Forward
Net Income	104.8	61.9	218.1	142.6
Dividends	(22.9)	(21.0)	(46.7)	(43.9)
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Roll Forward
Ending Balance		(0.4)		(0.4)
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity Roll Forward
Foreign currency translation adjustment	23.8	23.3	(20.2)	(48.0)
Pension and postretirement liability adjustments	(1.7)	(1.5)	(3.3)	(2.8)
Change in fair value of marketable securities		0.5		0.1
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(0.2)	(2.6)	2.0	1.6
Treasury Stock
Stockholders' Equity Roll Forward
Purchase of treasury shares			26.3	42.3
Stock option exercise activity				8.4
Restricted shares surrendered (issued)		1.5		23.7
Payment, Tax Withholding, Share-based Payment Arrangement	(5.7)	(0.2)	(23.5)	(10.4)
Non controlling Interest
Stockholders' Equity Roll Forward
Net Income	2.4	(0.1)	5.1	3.2
Foreign currency translation adjustment	(0.6)	1.2	(1.0)	(6.3)
Other Comprehensive Income (Loss), Net of Tax, Change in Noncontrolling Interest				(0.5)
Pension and other postretirement liability adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax	60.1	64.1	60.1	64.1	$ 61.8	$ 63.4	$ 65.6	$ 66.9
Stockholders' Equity Roll Forward
Income tax benefit	$ 0.5	0.5	$ 1.1	$ 1.0
Accounting Standards Update 2016-13
Stockholders' Equity Roll Forward
Cumulative effect of change in accounting		$ 0.2