Business Combinations - Revenue and Earnings From Acquired Business (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Business Acquisition [Line Items]
Total revenues		$ 26,492	$ 21,252	$ 17,098
Pretax loss		$ 1,532	$ 2,561	$ 706
Slack
Business Acquisition [Line Items]
Total revenues	$ 592
Pretax loss	$ (1,105)