Business Combinations (Consideration Transferred) (Details) - USD ($) $ in Millions	1 Months Ended						12 Months Ended
	Oct. 31, 2019	Aug. 31, 2019	Jun. 30, 2019	Aug. 31, 2018	May 31, 2018	Jul. 31, 2015	Jan. 31, 2020		Jan. 31, 2019	[1],[2]	Jan. 31, 2018	[1],[2]
Business Acquisition [Line Items]
Loss on settlement of Salesforce.org reseller agreement			$ (166)				$ (166)		$ 0		$ 0
Tableau Software, Inc.
Business Acquisition [Line Items]
Cash		$ 1
Common stock issued		14,552
Fair value of stock options and restricted stock awards assumed		292
Total		$ 14,845
ClickSoftware Technologies Ltd.
Business Acquisition [Line Items]
Cash	$ 587
Common stock issued	663
Fair value of stock options and restricted stock awards assumed	81
Fair value of pre-existing relationship	55
Total	$ 1,386					$ 14
Salesforce.org
Business Acquisition [Line Items]
Cash			300
Loss on settlement of Salesforce.org reseller agreement			(166)				$ (166)	[1],[2]
Total			$ 134
Datorama
Business Acquisition [Line Items]
Cash				$ 136
Common stock issued				537
Fair value of stock options and restricted stock awards assumed				93
Total				$ 766
MuleSoft
Business Acquisition [Line Items]
Cash					$ 4,860
Common stock issued					1,178
Fair value of stock options and restricted stock awards assumed					387
Total					$ 6,425

[1] Amounts include amortization of intangible assets acquired through business combinations, as follows:  Fiscal Year Ended January 31, 202020192018Cost of revenues$440  $215  $166  Marketing and sales352  232  121  

[2] Amounts include stock-based expense, as follows:  Fiscal Year Ended January 31, 202020192018Cost of revenues$204  $161  $130  Research and development510  307  260  Marketing and sales852  643  469  General and administrative219  172  138