Leases - Supplemental Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jan. 23, 2021	Jan. 25, 2020
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities — operating cash flows	$ 201	$ 206
Right-of-use assets obtained in exchange for operating leases liabilities	$ 218	$ 77