Leases Lease Cost and Other Information (Details) - USD ($) $ in Millions		12 Months Ended
		Apr. 30, 2021	Apr. 30, 2020
Leases [Abstract]
Total lease cost	[1]	$ 41	$ 29
Cash paid for amounts included in the measurement of lease liabilities	[2]	26	21
Right-of-use assets obtained in exchange for new lease liabilities		$ 25	$ 35

[1] Consists primarily of operating lease cost. Other components of lease cost were not material.

[2] Classified within operating activities in the accompanying consolidated statement of cash flows.