Reportable Segments (Details 1) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Revenues, Assets, and Long-Lived Assets [Line Items]
Net sales	$ 2,092.0	$ 1,972.3	$ 1,957.8	$ 1,778.9	$ 1,902.1	$ 2,011.9	$ 2,021.5	$ 1,902.5	$ 7,801.0	$ 7,838.0	$ 7,357.1
Assets	16,970.4				16,711.3				16,970.4	16,711.3	15,301.2
Total long-lived assets (excluding goodwill and other intangible assets)	2,264.2				2,056.4				2,264.2	2,056.4	1,887.5
United States [Member]
Revenues, Assets, and Long-Lived Assets [Line Items]
Net sales									7,247.9	7,298.0	6,786.5
Assets	16,547.6				16,338.0				16,547.6	16,338.0	14,828.2
Long-lived assets	2,209.9				2,037.5				2,209.9	2,037.5	1,869.8
Total international [Member]
Revenues, Assets, and Long-Lived Assets [Line Items]
Net sales									553.1	540.0	570.6
Assets	422.8				373.3				422.8	373.3	473.0
Long-lived assets	54.3				18.9				54.3	18.9	17.7
Canada [Member]
Revenues, Assets, and Long-Lived Assets [Line Items]
Net sales									445.3	421.9	431.8
Assets	421.3				362.1				421.3	362.1	428.7
Long-lived assets	54.3				18.9				54.3	18.9	17.4
All other international [Member]
Revenues, Assets, and Long-Lived Assets [Line Items]
Net sales									107.8	118.1	138.8
Assets	1.5				11.2				1.5	11.2	44.3
Long-lived assets	$ 0.0				$ 0.0				$ 0.0	$ 0.0	$ 0.3