Business Combinations - Schedule of Pro Forma Information (Details) - Slack - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Business Acquisition [Line Items]
Total revenues	$ 6,863	$ 5,610	$ 19,606	$ 15,968
Pretax income	404	738	1,169	611
Net income	$ 545	$ 715	$ 1,108	$ 2,656