Stockholders' Equity - Restricted Stock Unit Activity and Related Share-Based Compensation Expense (Details) - Restricted Stock Units (RSUs) $ / shares in Units, shares in Thousands, $ in Billions	3 Months Ended
	Oct. 31, 2021 USD ($) $ / shares shares
Number of Shares
Nonvested at beginning of period (in shares) | shares	9,038
Granted (in shares) | shares	271
Vested (in shares) | shares	(627)
Forfeited (in shares) | shares	(361)
Nonvested at end of period (in shares) | shares	8,321
Weighted Average Grant Date Fair Value
Nonvested, weighted average grant date fair value, at beginning of period (in dollars per shares) | $ / shares	$ 345.86
Granted, weighted average grant date fair value (in dollars per shares) | $ / shares	555.65
Vested, weighted average grant date fair value (in dollars per shares) | $ / shares	275.10
Forfeited, weighted average grant date fair value (in dollars per shares) | $ / shares	270.71
Nonvested, weighted average grant date fair value, at end of period (in dollars per shares) | $ / shares	$ 361.30
Unrecognized compensation cost related to non-vested RSUs | $	$ 2.6
Weighted average vesting period, in years	2 years 10 months 24 days