Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 5,419	$ 4,513	$ 15,435	$ 12,247
Americas
Disaggregation of Revenue [Line Items]
Total revenues	3,758	3,216	10,724	8,649
Europe
Disaggregation of Revenue [Line Items]
Total revenues	1,149	880	3,253	2,421
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	$ 512	$ 417	$ 1,458	$ 1,177
Untied States | Geographic concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk percentage	96.00%	96.00%	96.00%	96.00%
Subscription and support
Disaggregation of Revenue [Line Items]
Total revenues	$ 5,085	$ 4,239	$ 14,500	$ 11,480
Sales
Disaggregation of Revenue [Line Items]
Total revenues	1,311	1,168	3,835	3,371
Service
Disaggregation of Revenue [Line Items]
Total revenues	1,376	1,140	3,931	3,247
Platform and Other
Disaggregation of Revenue [Line Items]
Total revenues	1,594	1,287	4,470	3,041
Marketing and Commerce
Disaggregation of Revenue [Line Items]
Total revenues	$ 804	$ 644	$ 2,264	$ 1,821