Goodwill and Acquired Intangible Assets - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning	$ 1,655	$ 1,611
Goodwill Acquired/ Adjusted	(1)	44
Goodwill, ending	1,654	1,655
Small Business & Self-Employed
Goodwill [Roll Forward]
Goodwill, beginning	1,518	1,496
Goodwill Acquired/ Adjusted	0	22
Goodwill, ending	1,518	1,518
Goodwill net of accumulated impairment losses			$ 114
Consumer
Goodwill [Roll Forward]
Goodwill, beginning	42	23
Goodwill Acquired/ Adjusted	0	19
Goodwill, ending	42	42
Strategic Partner
Goodwill [Roll Forward]
Goodwill, beginning	95	92
Goodwill Acquired/ Adjusted	(1)	3
Goodwill, ending	$ 94	$ 95