Business Combinations (Narrative) (Details) $ in Millions		1 Months Ended								3 Months Ended								12 Months Ended
	Apr. 30, 2019 USD ($)	Oct. 31, 2019 USD ($)	Aug. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	May 31, 2019 USD ($)	Aug. 31, 2018 USD ($)	May 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jul. 31, 2015 USD ($)	Jan. 31, 2020 USD ($)	Oct. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2020 USD ($)		Jan. 31, 2019 USD ($)		Jan. 31, 2018 USD ($) company
Business Acquisition [Line Items]
Weighted average remaining useful life																		5 years 3 months 18 days
Total revenues										$ 4,851	$ 4,513	$ 3,997	$ 3,737	$ 3,603	$ 3,392	$ 3,281	$ 3,006	$ 17,098		$ 13,282		$ 10,540
Loss on settlement of Salesforce.org reseller agreement				$ 166														$ 166		0	[1],[2]	0	[1],[2]
Useful Life																		5 years 3 months 18 days
Goodwill										$ 25,134				$ 12,851				$ 25,134		$ 12,851		7,314
Developed Technology Rights
Business Acquisition [Line Items]
Weighted average remaining useful life																		4 years 1 month 6 days
Useful Life																		4 years 1 month 6 days
Customer relationships
Business Acquisition [Line Items]
Weighted average remaining useful life																		6 years 6 months
Useful Life																		6 years 6 months
Tableau Software, Inc.
Business Acquisition [Line Items]
Transaction costs			$ 40
Consideration transferred			14,845
Finite-lived intangible assets acquired			$ 3,252
Share conversion ratio			1.103
Fair value of stock options and restricted stock awards assumed			$ 1,500
Fair value of stock options and restricted stock awards assumed			292
Assumed unvested options and restricted stock, allocated to future services			1,200
Cash			1
Intangible assets			3,252
Goodwill			10,806
Tableau Software, Inc. | Developed Technology Rights
Business Acquisition [Line Items]
Finite-lived intangible assets acquired			$ 2,000
Weighted average remaining useful life			5 years
Useful Life			5 years
Tableau Software, Inc. | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets acquired			$ 1,231
Weighted average remaining useful life			8 years
Useful Life			8 years
ClickSoftware Technologies Ltd.
Business Acquisition [Line Items]
Consideration transferred		$ 1,386							$ 14
Finite-lived intangible assets acquired			$ 276
Share conversion ratio		0.109592
Fair value of stock options and restricted stock awards assumed		$ 103
Fair value of stock options and restricted stock awards assumed		81
Assumed unvested options and restricted stock, allocated to future services		22									22
Remeasurement gain		39
Cash		587
Intangible assets		276									276
Goodwill		$ 1,132									$ 1,132
ClickSoftware Technologies Ltd. | Developed Technology Rights
Business Acquisition [Line Items]
Finite-lived intangible assets acquired			$ 215
Weighted average remaining useful life			4 years
Useful Life			4 years
ClickSoftware Technologies Ltd. | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets acquired			$ 61
Weighted average remaining useful life			8 years
Useful Life			8 years
Salesforce.org
Business Acquisition [Line Items]
Consideration transferred				134
Total revenues																		$ 228
Cash				300
Loss on settlement of Salesforce.org reseller agreement				166														$ 166	[1],[2]
Goodwill				$ 164
MapAnything, Inc.
Business Acquisition [Line Items]
Consideration transferred	$ 23				$ 213
Remeasurement gain					9
Intangible assets					53
Goodwill					$ 152
Datorama
Business Acquisition [Line Items]
Consideration transferred						$ 766
Finite-lived intangible assets acquired						$ 202
Share conversion ratio						0.4133
Fair value of stock options and restricted stock awards assumed						$ 170
Fair value of stock options and restricted stock awards assumed						93
Assumed unvested options and restricted stock, allocated to future services						77
Cash						136
Intangible assets						202
Goodwill						586
Datorama | Developed Technology Rights
Business Acquisition [Line Items]
Finite-lived intangible assets acquired						$ 159
Weighted average remaining useful life						4 years
Useful Life						4 years
Datorama | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets acquired						$ 42
Weighted average remaining useful life						8 years
Useful Life						8 years
MuleSoft
Business Acquisition [Line Items]
Consideration transferred							$ 6,425
Finite-lived intangible assets acquired							$ 1,279
Share conversion ratio							0.3680
Fair value of stock options and restricted stock awards assumed							$ 824
Fair value of stock options and restricted stock awards assumed							387
Assumed unvested options and restricted stock, allocated to future services							437
Cash							4,860
Intangible assets							1,279
Goodwill							4,816
MuleSoft | General and administrative
Business Acquisition [Line Items]
Transaction costs							24
Consideration transferred							6,400
MuleSoft | Developed Technology Rights
Business Acquisition [Line Items]
Finite-lived intangible assets acquired							$ 224
Weighted average remaining useful life							4 years
Useful Life							4 years
MuleSoft | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets acquired							$ 1,046
Weighted average remaining useful life							8 years
Useful Life							8 years
CloudCraze
Business Acquisition [Line Items]
Consideration transferred								$ 190
Goodwill								134									$ 134
CloudCraze | Developed Technology Rights
Business Acquisition [Line Items]
Finite-lived intangible assets acquired								58
CloudCraze | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets acquired								$ 58
Two Companies
Business Acquisition [Line Items]
Consideration transferred																						$ 38
Number of companies acquired | company																						2
Intangible assets																						$ 3
Goodwill																						$ 35
Minimum | MapAnything, Inc.
Business Acquisition [Line Items]
Weighted average remaining useful life					4 years
Useful Life					4 years
Minimum | CloudCraze | Developed Technology Rights
Business Acquisition [Line Items]
Weighted average remaining useful life								1 year
Useful Life								1 year
Minimum | CloudCraze | Customer relationships
Business Acquisition [Line Items]
Weighted average remaining useful life								1 year
Useful Life								1 year
Maximum | MapAnything, Inc.
Business Acquisition [Line Items]
Weighted average remaining useful life					5 years
Useful Life					5 years
Maximum | CloudCraze | Developed Technology Rights
Business Acquisition [Line Items]
Weighted average remaining useful life								7 years
Useful Life								7 years
Maximum | CloudCraze | Customer relationships
Business Acquisition [Line Items]
Weighted average remaining useful life								7 years
Useful Life								7 years

[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