Retirement-Related Benefits - Contributions, Defined Benefit Pension Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Retirement-Related Benefits
Total	$ 1,847	$ 1,962
Pension Plans, Including Multi-employer Plans \| Non-U.S. Plans
Retirement-Related Benefits
Estimated cash contributions to the defined benefit plans in next fiscal year	$ 200

Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-18

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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