Segment Information - Company's Segments Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Net sales:
Net sales	$ 1,014.6	$ 1,012.4	$ 3,066.1	$ 3,121.5
Earnings (losses) from operations:
Earnings from operations for segments	169.3	185.8	615.3	685.2
Americas
Net sales:
Net sales	422.5	442.1	1,283.6	1,342.2
Earnings (losses) from operations:
Earnings from operations for segments	60.5	60.0	204.3	230.4
Asia-Pacific
Net sales:
Net sales	294.1	294.0	915.8	923.1
Earnings (losses) from operations:
Earnings from operations for segments	42.9	66.2	202.1	245.8
Japan
Net sales:
Net sales	169.3	142.1	469.3	447.3
Earnings (losses) from operations:
Earnings from operations for segments	57.4	49.3	167.0	165.3
Europe
Net sales:
Net sales	111.3	114.1	330.0	342.6
Earnings (losses) from operations:
Earnings from operations for segments	12.1	12.3	44.1	44.2
Total reportable segments
Net sales:
Net sales	997.2	992.3	2,998.7	3,055.2
Earnings (losses) from operations:
Earnings from operations for segments	172.9	187.8	617.5	685.7
Other
Net sales:
Net sales	17.4	20.1	67.4	66.3
Earnings (losses) from operations:
Earnings from operations for segments	$ (3.6)	$ (2.0)	$ (2.2)	$ (0.5)