Segment Information - Company's Segments Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Net sales:
Net sales	$ 1,048.5	$ 1,075.9	$ 2,051.6	$ 2,109.1
Earnings (losses) from operations:
Earnings from operations for segments	236.2	249.8	446.0	499.3
Americas
Net sales:
Net sales	454.8	474.9	861.1	900.1
Earnings (losses) from operations:
Earnings from operations for segments	86.9	95.8	143.8	170.4
Asia-Pacific
Net sales:
Net sales	297.6	300.5	621.7	629.1
Earnings (losses) from operations:
Earnings from operations for segments	73.2	79.6	159.2	179.6
Japan
Net sales:
Net sales	155.3	154.6	300.0	305.2
Earnings (losses) from operations:
Earnings from operations for segments	56.2	57.6	109.6	115.9
Europe
Net sales:
Net sales	116.3	121.4	218.8	228.4
Earnings (losses) from operations:
Earnings from operations for segments	19.7	17.6	31.9	31.9
Total reportable segments
Net sales:
Net sales	1,024.0	1,051.4	2,001.6	2,062.8
Earnings (losses) from operations:
Earnings from operations for segments	236.0	250.6	444.5	497.8
Other
Net sales:
Net sales	24.5	24.5	50.0	46.3
Earnings (losses) from operations:
Earnings from operations for segments	$ 0.2	$ (0.8)	$ 1.5	$ 1.5