Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Beginning Balance	$ 2,367.3	$ 1,967.6	$ 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	781.7	930.6	781.7	930.6	778.6	740.7	924.4	937.6
Retained Earnings (Accumulated Deficit)	1,576.2	2,073.4	1,576.2	2,073.4	1,510.9	1,339.5	2,005.7	1,907.4
Accumulated Other Comprehensive Income (Loss), Net of Tax	(12.3)	(39.3)	(12.3)	(39.3)	19.8	41.3	(99.2)	(50.1)
Treasury Stock, Value	(89.4)	(989.7)	(89.4)	(989.7)	(59.1)	(9.3)	(1,000.4)	(979.8)
Stockholders' Equity Attributable to Noncontrolling Interest	79.5	70.9	79.5	70.9	76.4	72.3	84.0	86.6
Stockholders' Equity Roll Forward
Net Income	91.6	91.3	314.8	237.1
Foreign currency translation adjustments	(32.9)	63.5	(54.1)	9.2
Pension and postretirement liability adjustments	(1.5)	(1.2)	(4.8)	(4.0)
Change in fair value of marketable securities		(0.1)	0.0	0.0
Payments of Ordinary Dividends	0.6	16.1	0.6	16.1
Dividends	$ (22.8)	$ (21.1)	$ (69.5)	$ (65.0)
Dividend per share	$ 0.30	$ 0.28	$ 0.89	$ 0.84
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	$ 3.1	$ 7.8	$ 15.6	$ 19.2
Purchase of treasury shares	(30.3)		(56.6)	(42.3)
Restricted shares surrendered (issued)		0.0		0.0
Payment, Tax Withholding, Share-based Payment Arrangement		(1.6)	(23.5)	(12.0)
Ending Balance	2,376.4	2,099.0	2,376.4	2,099.0
Income tax benefit (expense)	(0.6)	1.3	(0.2)	1.5
Other Comprehensive Income (Loss), Net of Tax, Change in Noncontrolling Interest				(0.5)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture		10.7	25.4	18.2
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments and Tax	2.5	(1.8)	4.5	(0.2)
Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Roll Forward
Net Income	91.6		314.8
Ending Balance		(0.4)		(0.4)
Other Paid-In Capital
Stockholders' Equity Roll Forward
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	3.1	7.8	15.6	19.2
Restricted shares surrendered (issued)		(0.1)		(23.8)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture		1.5	25.4	2.4
Retained Earnings
Stockholders' Equity Roll Forward
Net Income	88.1	88.8	306.2	231.4
Dividends	(22.8)	(21.1)	(69.5)	(65.0)
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 adjustments	(33.1)	63.0	(53.3)	15.0
Pension and postretirement liability adjustments	(1.5)	(1.2)	(4.8)	(4.0)
Change in fair value of marketable securities		(0.1)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments and Tax	2.5	(1.8)	4.5	(0.2)
Treasury Stock
Stockholders' Equity Roll Forward
Purchase of treasury shares	30.3		56.6	42.3
Restricted shares surrendered (issued)		0.1		23.8
Payment, Tax Withholding, Share-based Payment Arrangement		(1.6)	(23.5)	(12.0)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture		12.2		20.6
Non controlling Interest
Stockholders' Equity Roll Forward
Net Income	3.5	2.5	8.6	5.7
Foreign currency translation adjustments	0.2	0.5	(0.8)	(5.8)
Payments of Ordinary Dividends	0.6	16.1	0.6	16.1
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	58.6	62.9	58.6	62.9	$ 60.1	$ 63.4	$ 64.1	$ 66.9
Stockholders' Equity Roll Forward
Income tax benefit (expense)	$ 0.5	$ 0.4	$ 1.6	1.4
Accounting Standards Update 2016-13
Stockholders' Equity Roll Forward
Cumulative effect of change in accounting				$ 0.2