Income Taxes - Provision for income taxes from continuing operations (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2019
Current:
Federal	$ 399	$ 372	$ 271
State	121	79	67
Foreign	17	21	14
Total current	537	472	352
Deferred:
Federal	(33)	(47)	(23)
State	(11)	(47)	(4)
Foreign	1	(6)	(1)
Total deferred	(43)	(100)	(28)
Total provision for income taxes	$ 494	$ 372	$ 324