CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Comprehensive Income [Abstract]
Net earnings	$ 100.2	$ 95.1	$ 308.2	$ 288.3
Other comprehensive (loss) earnings, net of tax
Foreign currency translation adjustments	(10.0)	(13.5)	41.3	13.6
Unrealized (loss) gain on marketable securities	(1.3)	(0.1)	(1.6)	1.9
Unrealized gain (loss) on hedging instruments	1.6	(7.6)	(0.4)	4.8
Net unrealized gain on benefit plans	2.0	2.2	6.0	6.6
Other comprehensive earnings (loss), net of tax	(7.7)	(19.0)	45.3	26.9
Comprehensive earnings	$ 92.5	$ 76.1	$ 353.5	$ 315.2