Condensed Statements of Consolidated Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 188.5	$ 194.6	$ 321.5	$ 321.4
Other comprehensive income (loss):
Foreign currency translation adjustments	(5.6)	(13.1)	(11.7)	21.9
Cash flow hedging derivative activity, net of tax	6.1	0.8	8.2	2.4
Pension and other postretirement benefit plans activity, net of tax	1.6	5.9	3.2	5.7
Available-for-sale securities activity, net of tax	0.3	(0.6)	0.6	(0.3)
Total Other Comprehensive Income (Loss)	2.4	(7.0)	0.3	29.7
Comprehensive Income	$ 190.9	$ 187.6	$ 321.8	$ 351.1