CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Retained Earnings	Accumulated Other Comprehensive Loss	Common Stock	Additional Paid-In Capital	Non- Controlling Interests
Beginning balance 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of restricted stock units	22.6				22.6
Exercise of stock options and vesting of restricted stock units (shares)				0.5
Shares withheld related to net share settlement of share-based compensation	(7.6)				(7.6)
Shares withheld related to net share settlement of share-based compensation (shares)				(0.1)
Share-based compensation expense	30.3				30.3
Purchase and retirement of Common Stock	$ (377.3)	(351.8)			(25.5)
Purchase and retirement of Common Stock (shares)	(3.0)			(3.0)
Cash dividends on Common Stock	$ (196.9)	(196.9)
Accrued dividends on share-based awards	(0.8)	(0.9)			0.1
Other comprehensive earnings (loss), net of tax	(81.5)		(81.5)
Net earnings	381.9	381.9
Non-controlling interests	(0.4)					(0.4)
Ending balance at Oct. 31, 2018	$ 3,022.4	1,948.6	(217.7)	$ 1.2	1,275.9	14.4
Ending balance (shares) at Oct. 31, 2018	121.9			121.9
Beginning balance at Jul. 31, 2018	$ 3,071.5	1,986.8	(196.7)	$ 1.2	1,265.6	14.6
Beginning balance (shares) at Jul. 31, 2018				122.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of restricted stock units	5.8				5.8
Exercise of stock options and vesting of restricted stock units (shares)				0.1
Shares withheld related to net share settlement of share-based compensation	(0.8)				(0.8)
Share-based compensation expense	10.5				10.5
Purchase and retirement of Common Stock	$ (71.0)	(65.9)			(5.1)
Purchase and retirement of Common Stock (shares)	(0.6)			(0.6)
Cash dividends on Common Stock	$ (67.2)	(67.2)
Accrued dividends on share-based awards	(0.1)	0.0			(0.1)
Other comprehensive earnings (loss), net of tax	(21.0)		(21.0)
Net earnings	94.9	94.9
Non-controlling interests	(0.2)					(0.2)
Ending balance at Oct. 31, 2018	$ 3,022.4	1,948.6	(217.7)	$ 1.2	1,275.9	14.4
Ending balance (shares) at Oct. 31, 2018	121.9			121.9
Beginning balance at Jan. 31, 2019	$ 3,130.9	2,045.6	(204.8)	$ 1.2	1,275.4	13.5
Beginning balance (shares) at Jan. 31, 2019	121.5			121.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of restricted stock units	$ 4.3				4.3
Exercise of stock options and vesting of restricted stock units (shares)				0.3
Shares withheld related to net share settlement of share-based compensation	(9.6)				(9.6)
Shares withheld related to net share settlement of share-based compensation (shares)				(0.1)
Share-based compensation expense	20.0				20.0
Purchase and retirement of Common Stock	$ (163.4)	(148.0)			(15.4)
Purchase and retirement of Common Stock (shares)	(1.8)			(1.8)
Cash dividends on Common Stock	$ (206.7)	(206.7)
Accrued dividends on share-based awards	(1.6)	(1.9)			0.3
Other comprehensive earnings (loss), net of tax	7.8		7.8
Net earnings	339.9	339.9
Non-controlling interests	(0.9)					(0.9)
Ending balance at Oct. 31, 2019	$ 3,142.5	2,076.7	(223.0)	$ 1.2	1,275.0	12.6
Ending balance (shares) at Oct. 31, 2019	119.9			119.9
Beginning balance at Jul. 31, 2019	$ 3,193.1	2,139.4	(237.0)	$ 1.2	1,276.5	13.0
Beginning balance (shares) at Jul. 31, 2019				120.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of restricted stock units	1.7				1.7
Shares withheld related to net share settlement of share-based compensation	(0.5)				(0.5)
Share-based compensation expense	4.8				4.8
Purchase and retirement of Common Stock	$ (78.0)	(70.4)			(7.6)
Purchase and retirement of Common Stock (shares)	(0.9)			(0.9)
Cash dividends on Common Stock	$ (69.7)	(69.7)
Accrued dividends on share-based awards	(0.9)	(1.0)			0.1
Other comprehensive earnings (loss), net of tax	14.0		14.0
Net earnings	78.4	78.4
Non-controlling interests	(0.4)					(0.4)
Ending balance at Oct. 31, 2019	$ 3,142.5	$ 2,076.7	$ (223.0)	$ 1.2	$ 1,275.0	$ 12.6
Ending balance (shares) at Oct. 31, 2019	119.9			119.9