Fair Value Measurements (Details) - USD ($) $ in Millions	Jul. 31, 2021	Apr. 30, 2021	Jul. 31, 2020	Apr. 30, 2020
Assets:
Cash and cash equivalents, Carrying Amount	$ 1,172	$ 1,150	$ 908	$ 675
Cash and cash equivalents, Fair Value	1,172	1,150
Liabilities:
Short-term borrowings, Carrying Amount	155	205
Short-term borrowings, Fair Value	155	205
Long-term debt, Carrying Amount	2,346	2,354
Fair Value, Inputs, Level 2 [Member]
Assets:
Currency derivatives, Fair Value	4	3
Liabilities:
Currency derivatives, Fair Value	12	31
Long-term debt, Fair Value	2,718	2,663
Foreign Exchange Contract [Member]
Assets:
Currency derivatives, Carrying Amount	4	3
Liabilities:
Currency derivatives, Carrying Amount	$ 12	$ 31