Stock Compensation - Effect on Shares Outstanding and Treasury Shares (Details) - shares shares in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change In Treasury Stock Roll Forward [Roll Forward]
Treasury stock (in shares)	817	821	809	796
Repurchases (in shares)	3	23	27
Shares issued (in shares)	(7)	(11)	(14)

Number, after forfeiture, of shares or units issued under share-based payment arrangement. Excludes shares or units issued under employee stock ownership plan (ESOP).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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