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