Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2019
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation and qualifying accounts, beginning balance	$ 12	$ 3	$ 5
Additions Charged to Expense/ Revenue	92	68	59
Deductions	(8)	(59)	(61)
Valuation and qualifying accounts, ending balance	96	12	3
Reserve for returns and credits
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation and qualifying accounts, beginning balance	24	24	17
Additions Charged to Expense/ Revenue	168	170	190
Deductions	(171)	(170)	(183)
Valuation and qualifying accounts, ending balance	21	24	24
Reserve for promotional discounts and rebates
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation and qualifying accounts, beginning balance	11	11	10
Additions Charged to Expense/ Revenue	62	73	92
Deductions	(63)	(73)	(91)
Valuation and qualifying accounts, ending balance	$ 10	$ 11	$ 11