Leases - Lease Expenses (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Apr. 25, 2020	Apr. 25, 2020
Leases [Abstract]
Operating lease expense	$ 101	$ 315
Short-term lease expense	18	51
Variable lease expense	37	116
Total lease expense	$ 156	$ 482