Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10)(1))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=120320667&loc=SL49117168-202975

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Acquisitions/Divestitures - Goodwill (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Jul. 09, 2019	Dec. 31, 2018
Acquisitions
Goodwill	$ 57,833	$ 58,222		$ 36,265
Red Hat, Inc.
Acquisitions
Goodwill	$ 23,000		$ 22,986
Expected percent of goodwill deductible for tax purposes	6.00%
Cloud & Cognitive Software \| Red Hat, Inc.
Acquisitions
Goodwill	$ 18,400
Global Technology Services \| Red Hat, Inc.
Acquisitions
Goodwill	3,100
Global Business Services \| Red Hat, Inc.
Acquisitions
Goodwill	1,100
Systems \| Red Hat, Inc.
Acquisitions
Goodwill	$ 400