Derivative Financial Instruments and Hedging Activities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Total amounts presented in the accompanying consolidated statements of operations for line items affected by the net gains (losses) shown above: [Abstract]
Sales	$ 1,222	$ 1,178	$ 3,481	$ 3,404
Other income (expense), net	9	4	13	13
Foreign Currency Denominated Debt [Member]
Foreign currency-denominated debt designated as net investment hedge: [Abstract]
Net gain (loss) recognized in AOCI	(33)	(5)	(66)	(2)
Currency derivatives [Member]
Currency derivatives designated as cash flow hedges: [Abstract]
Net gain (loss) recognized in AOCI	(39)	4	(73)	17
Currency derivatives [Member] | Sales [Member]
Currency derivatives designated as cash flow hedges: [Abstract]
Net gain (loss) reclassified from AOCI into earnings	4	5	21	16
Currency derivatives not designated as hedging instruments: [Abstract]
Net gain (loss) recognized in earnings	(6)	(1)	(11)	(2)
Currency derivatives [Member] | Other Income [Member]
Currency derivatives not designated as hedging instruments: [Abstract]
Net gain (loss) recognized in earnings	$ 4	$ 4	$ 15	$ 6