Leases - Supplemental Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2021	Oct. 31, 2020
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 24	$ 14
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 43	$ 19