CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - 9 months ended Oct. 31, 2017 - USD ($) shares in Millions, $ in Millions	Total	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Non-controlling Interests [Member]
Beginning Balances at Jan. 31, 2017	$ 3,028.4	$ 2,078.3	$ (256.2)	$ 1.2	$ 1,190.2	$ 14.9
Beginning Balance, Shares at Jan. 31, 2017	124.5			124.5
Exercise of stock options and vesting of restricted stock units ("RSUs")	$ 13.9	0.0	0.0	$ 0.0	13.9	0.0
Exercise of stock options and vesting of restricted stock units ("RSUs"), shares				0.6
Adjustments Related to Tax Withholding for Share-based Compensation	(7.5)	0.0	0.0	$ 0.0	(7.5)	0.0
Shares Paid for Tax Withholding for Share Based Compensation				(0.1)
Share-based compensation expense	21.8	0.0	0.0	$ 0.0	21.8	0.0
Purchase and retirement of Common Stock, Value	$ (60.2)	(55.0)	0.0	$ 0.0	(5.2)	0.0
Purchase and retirement of Common Stock, Shares	(0.7)			(0.7)
Cash dividends on Common Stock	$ (180.6)	(180.6)	0.0	$ 0.0	0.0	0.0
Accrued dividends on share-based awards	(0.5)	(0.5)	0.0	0.0	0.0	0.0
Other comprehensive earnings (loss), net of tax	45.3	0.0	45.3	0.0	0.0	0.0
Net earnings	308.2	308.2	0.0	0.0	0.0	0.0
Non-controlling interests	0.3	0.0	0.0	0.0	0.0	0.3
Ending Balances at Oct. 31, 2017	$ 3,169.1	$ 2,150.4	$ (210.9)	$ 1.2	$ 1,213.2	$ 15.2
Ending Balance, Shares at Oct. 31, 2017	124.3			124.3