STATEMENT OF CHANGES IN EQUITY AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Statement of Changes in Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,157.6	$ 1,190.8
Effect of accounting change on prior years			$ 0.1	$ (2.3)
Adjusted beginning balance			1,157.7	1,188.5
Net earnings	61.1	77.9
(Earnings) loss attributable to noncontrolling interest, net of tax	0.1	0.0
Dividends declared (See Note 7)	(49.9)	(47.2)
Dividends paid to noncontrolling interest		(0.2)
Treasury stock purchased	(11.7)	(55.3)
Treasury stock issued	13.8	3.9
Foreign currency translation adjustments	8.8	16.7
Cash flow hedges, net of tax	3.9	2.3
Defined benefit pension plans, net of tax	0.5	0.4
Stock-based compensation transactions, net of tax	11.0	9.3
Ending balance	1,195.2	1,196.3
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	2,613.8	2,511.3
Effect of accounting change on prior years			0.1	(2.3)
Adjusted beginning balance			2,613.9	2,509.0
Net earnings	61.1	77.9
(Earnings) loss attributable to noncontrolling interest, net of tax	0.1
Dividends declared (See Note 7)	(51.2)	(48.6)
Ending balance	2,623.9	2,538.3
Common Stock & Additional Contributed Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	529.1	516.7
Adjusted beginning balance			529.1	516.7
Dividends declared (See Note 7)	1.3	1.4
Treasury stock issued	(14.6)	(10.8)
Stock-based compensation transactions, net of tax	11.0	9.3
Ending balance	526.8	516.6
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,908.3)	(1,828.3)
Adjusted beginning balance			(1,908.3)	(1,828.3)
Treasury stock purchased	(11.7)	(55.3)
Treasury stock issued	28.4	14.7
Ending balance	(1,891.6)	(1,868.9)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	0.6	0.6
Adjusted beginning balance			0.6	0.6
(Earnings) loss attributable to noncontrolling interest, net of tax	(0.1)
Dividends paid to noncontrolling interest		(0.2)
Ending balance	0.5	0.4
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(77.6)	(9.5)
Adjusted beginning balance			$ (77.6)	$ (9.5)
Foreign currency translation adjustments	8.8	16.7
Cash flow hedges, net of tax	3.9	2.3
Defined benefit pension plans, net of tax	0.5	0.4
Ending balance	$ (64.4)	$ 9.9