Stockholders' Equity - Restricted Stock Unit Activity and Related Share-Based Compensation Expense (Details) - Restricted Stock Units (RSUs) $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Apr. 30, 2018 USD ($) $ / shares shares
Number of Shares
Nonvested at beginning of period (in shares) | shares	8,636
Granted (in shares) | shares	687
Unregistered restricted stock granted in connection with acquisitions (in shares) | shares	75
Vested (in shares) | shares	(1,074)
Forfeited (in shares) | shares	(1,033)
Nonvested at end of period (in shares) | shares	7,291
Weighted Average Grant Date Fair Value
Nonvested, Weighted Average Grant Date Fair Value, at beginning of period (in dollars per shares) | $ / shares	$ 98.76
Granted, Weighted Average Grant Date Fair Value (in dollars per shares) | $ / shares	158.18
Unregistered restricted stock granted in connection with acquisitions (in dollars per share) | $ / shares	163.00
Vested, Weighted Average Grant Date Fair Value (in dollars per shares) | $ / shares	79.40
Forfeited, Weighted Average Grant Date Fair Value (in dollars per shares) | $ / shares	86.95
Nonvested, Weighted Average Grant Date Fair Value, at end of period (in dollars per shares) | $ / shares	$ 109.55
Unrecognized compensation cost related to non-vested RSUs | $	$ 509
Weighted average vesting period, in years	2 years