Leases ROU Assets and Liabilities (Details) - USD ($) $ in Millions	Apr. 30, 2022	Apr. 30, 2021
Leases [Abstract]
Right-of-use assets	$ 74	$ 67
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]
Lease Liabilities:
Current	$ 21	$ 20
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]
Non-current	$ 54	$ 49
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]
Total	$ 75	$ 69
Weighted-average discount rate	1.80%	1.90%
Weighted-average remaining term	5 years	5 years 3 months 18 days