Goodwill and Acquired Intangible Assets - Intangible Assets Acquired (Details) - USD ($) $ in Millions	6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jul. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 4,161		$ 744
Accumulated amortization	(777)		(716)
Acquired intangible assets, net	$ 3,384		28
Weighted average life in years	14 years	4 years
Customer Lists / User Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 3,038		256
Accumulated amortization	(282)		(248)
Acquired intangible assets, net	$ 2,756		8
Weighted average life in years	15 years	5 years
Purchased Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 681		421
Accumulated amortization	(426)		(404)
Acquired intangible assets, net	$ 255		17
Weighted average life in years	5 years	3 years
Trade Names and Logos
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 400		25
Accumulated amortization	(29)		(25)
Acquired intangible assets, net	$ 371		0
Weighted average life in years	15 years	0 years
Covenants Not to Compete or Sue
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 42		42
Accumulated amortization	(40)		(39)
Acquired intangible assets, net	$ 2		$ 3
Weighted average life in years	3 years	3 years