Condensed Statements of Consolidated Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 230.8	$ 211.2	$ 467.8	$ 365.8
Other comprehensive income (loss):
Foreign currency translation adjustments	2.3	0.6	15.2	5.1
Cash flow hedging derivative activity, net of tax	2.7	(33.8)	5.3	(74.6)
Pension and other postretirement benefit plans activity, net of tax	28.7	1.4	30.4	2.5
Available-for-sale securities activity, net of tax	(0.3)	0.1	0.6	0.4
Total Other Comprehensive Income (Loss)	33.4	(31.7)	51.5	(66.6)
Comprehensive Income	$ 264.2	$ 179.5	$ 519.3	$ 299.2