CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - 6 months ended Jul. 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")	$ 10.7	0.0	0.0	$ 0.0	10.7	0.0
Exercise of stock options and vesting of restricted stock units ("RSUs"), shares				0.4
Adjustments Related to Tax Withholding for Share-based Compensation	(7.2)	0.0	0.0	$ 0.0	(7.2)	0.0
Shares Paid for Tax Withholding for Share Based Compensation				(0.1)
Share-based compensation expense	16.0	0.0	0.0	$ 0.0	16.0	0.0
Purchase and retirement of Common Stock, Value	$ (32.5)	(29.7)	0.0	$ 0.0	(2.8)	0.0
Purchase and retirement of Common Stock, Shares	(0.4)			(0.3)
Cash dividends on Common Stock	$ (118.3)	(118.3)	0.0	$ 0.0	0.0	0.0
Accrued dividends on share-based awards	(0.3)	(0.3)	0.0	0.0	0.0	0.0
Other comprehensive earnings (loss), net of tax	53.0	0.0	53.0	0.0	0.0	0.0
Net earnings	207.9	207.9	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 Jul. 31, 2017	$ 3,158.0	$ 2,137.9	$ (203.2)	$ 1.2	$ 1,206.9	$ 15.2
Ending Balance, Shares at Jul. 31, 2017	124.5			124.5