Changes in Stockholders' Equity (Schedule of Stockholders' Equity) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance beginning of period	$ 2,690.6	$ 3,019.0	$ 2,907.0	$ 2,993.5
Stock compensation	10.1	12.3	12.7	24.8
Issuance of stock awards	(0.1)	(0.3)	(15.7)	(22.9)
AdjustmentstoAdditionalPaidinCapitalSharebasedCompensationExerciseofSSARs		3.1	0.1	3.4
Net income	60.0	140.4	126.3	206.1
Net income (loss)	69.7	140.8	134.4	205.9
Other comprehensive (loss) income, net of reclassification adjustments:
Foreign currency translation adjustments	(30.3)	4.4	(245.1)	16.6
Defined benefit pension plans, net of tax	3.4	3.0	6.9	6.0
Deferred gains and losses on derivatives, net of tax	(4.4)	4.8	5.0	0.7
Payment of dividends to stockholders	(11.9)	(12.2)	(24.0)	(23.7)
Purchases and retirement of common stock		(40.0)	(55.0)	(70.0)
Investment by noncontrolling interests	0.1	0.4		1.0
Balance end of period	2,717.5	3,128.7	2,717.5	3,128.7
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			(0.5)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance beginning of period	0.8	0.8	0.8	0.8
Other comprehensive (loss) income, net of reclassification adjustments:
Balance end of period	0.8	0.8	0.8	0.8
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance beginning of period	0.0	9.7	4.7	10.2
Stock compensation	10.2	12.3	16.1	24.8
Issuance of stock awards	(0.1)	(0.2)	(7.3)	(13.2)
AdjustmentstoAdditionalPaidinCapitalSharebasedCompensationExerciseofSSARs		(3.1)		(3.1)
Other comprehensive (loss) income, net of reclassification adjustments:
Purchases and retirement of common stock		(11.6)	(3.4)	(11.6)
Balance end of period	10.1	7.1	10.1	7.1
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance beginning of period	4,432.7	4,491.0	4,443.5	4,477.3
Stock compensation	(0.1)		(3.4)
Issuance of stock awards	0.0	(0.1)	(8.4)	(9.7)
AdjustmentstoAdditionalPaidinCapitalSharebasedCompensationExerciseofSSARs			0.1	0.3
Net income	69.7	140.8	134.4	205.9
Other comprehensive (loss) income, net of reclassification adjustments:
Payment of dividends to stockholders	(11.9)	(12.2)	(24.0)	(23.7)
Purchases and retirement of common stock		(28.4)	(51.6)	(58.4)
Balance end of period	4,490.4	4,591.1	4,490.4	4,591.1
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance beginning of period	(1,791.4)	(1,545.8)	(1,595.2)	(1,555.4)
Other comprehensive (loss) income, net of reclassification adjustments:
Foreign currency translation adjustments	(32.8)	3.7	(241.9)	14.4
Defined benefit pension plans, net of tax	3.4	3.0	6.9	6.0
Deferred gains and losses on derivatives, net of tax	(4.4)	4.8	5.0	0.7
Balance end of period	(1,825.2)	(1,534.3)	(1,825.2)	(1,534.3)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance beginning of period	48.5	63.3	53.2	60.6
Net income	(9.7)	(0.4)	(8.1)	0.2
Other comprehensive (loss) income, net of reclassification adjustments:
Foreign currency translation adjustments	2.5	0.7	(3.2)	2.2
Investment by noncontrolling interests	0.1	0.4		1.0
Balance end of period	$ 41.4	$ 64.0	41.4	$ 64.0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			$ (0.5)