Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Jul. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	$ 84		$ 43
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Upward adjustments to non-marketable equity securities	46	$ 8
Cumulative upward adjustments to non-marketable equity securities	$ 63