Revenues - Disaggregation of Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 3,997	$ 3,281	$ 7,734	$ 6,287
Americas
Disaggregation of Revenue [Line Items]
Total revenues	2,816	2,338	5,433	4,439
Europe
Disaggregation of Revenue [Line Items]
Total revenues	786	629	1,541	1,235
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	$ 395	$ 314	$ 760	$ 613
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	$ 3,745	$ 3,060	$ 7,241	$ 5,870
Sales Cloud
Disaggregation of Revenue [Line Items]
Total revenues	1,130	1,004	2,203	1,969
Service Cloud
Disaggregation of Revenue [Line Items]
Total revenues	1,087	892	2,107	1,740
Salesforce Platform and Other
Disaggregation of Revenue [Line Items]
Total revenues	912	712	1,754	1,287
Marketing and Commerce Cloud
Disaggregation of Revenue [Line Items]
Total revenues	$ 616	$ 452	$ 1,177	$ 874