CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) - 3 months ended Apr. 30, 2018 - 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, 2018	$ 3,248.2	$ 2,114.2	$ (138.0)	$ 1.2	$ 1,256.0	$ 14.8
Beginning Balance, Shares at Jan. 31, 2018	124.5			124.5
Exercise of stock options and vesting of restricted stock units	$ 4.5	0.0	0.0	$ 0.0	4.5	0.0
Exercise of stock options and vesting of restricted stock units, shares				0.2
Shares withheld related to net share settlement of share-based compensation	(6.5)	0.0	0.0	$ 0.0	(6.5)	0.0
Shares Paid for Tax Withholding for Share Based Compensation				(0.1)
Share-based compensation expense	9.0	0.0	0.0	$ 0.0	9.0	0.0
Purchase and retirement of Common Stock, Value	$ (40.5)	(37.1)	0.0	$ 0.0	(3.4)	0.0
Purchase and retirement of Common Stock, Shares	(0.4)			(0.4)
Cash dividends on Common Stock	$ (62.2)	(62.2)	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 (loss) earnings, net of tax	(29.9)	0.0	(29.9)	0.0	0.0	0.0
Net earnings	142.3	142.3	0.0	0.0	0.0	0.0
Non-controlling interests	0.1	0.0	0.0	0.0	0.0	0.1
Ending Balances at Apr. 30, 2018	$ 3,268.6	2,159.0	(166.1)	$ 1.2	1,259.6	14.9
Ending Balance, Shares at Apr. 30, 2018	124.2			124.2
Cumulative effect adjustment from adoption of new accounting standards	$ 3.9	$ 2.1	$ 1.8	$ 0.0	$ 0.0	$ 0.0