Goodwill and Other Intangible Assets (Details) $ in Millions	9 Months Ended
Jan. 31, 2021 USD ($)
Goodwill [Roll Forward]
Balance at April 30, 2020	$ 756
Sale of business (Note 14)	(4)
Acquisition (Note 14)	6
Foreign currency translation adjustment	16
Balance at January 31, 2021	774
Indefinite-lived Intangible Assets [Roll Forward]
Balance at April 30, 2020	635
Sale of business (Note 14)	(1)
Acquisition (Note 14)	8
Foreign currency translation adjustment	34
Balance at January 31, 2021	$ 676

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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