Revenues - Contract Balances, Unearned Revenue and Remaining Performance Obligation (Details) $ in Millions	12 Months Ended
	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Aug. 31, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Contract asset	$ 449	$ 215
Percent of revenue recognized	0.50
Unearned Revenue [Roll Forward]
Unearned revenue, beginning of period	$ 8,564	6,995
Billings and other	18,662	14,770
Contribution from contract asset	101	13
Unearned revenue from business combinations	433	68
Unearned revenue, end of period	10,662	8,564
Remaining Performance Obligation
Current	15,000	11,900
Noncurrent	15,800	13,800
Total	30,800	25,700
Salesforce.org
Remaining Performance Obligation
Total	450
Tableau Software, Inc.
Disaggregation of Revenue [Line Items]
Contract asset			$ 131
Remaining Performance Obligation
Total	650
Revenue recognized ratably over time
Unearned Revenue [Roll Forward]
Revenue recognized	(15,586)	(12,426)
Revenue recognized over time as delivered
Unearned Revenue [Roll Forward]
Revenue recognized	(716)	(629)
Revenue recognized at a point in time
Unearned Revenue [Roll Forward]
Revenue recognized	$ (796)	$ (227)