Consolidated Statement of Changes in Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common stock [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss), net of tax [Member]	Treasury stock, at cost [Member]	Common shares outstanding [Member]
Balance, beginning of year at Dec. 31, 2020		$ 23,743	$ 38,771	$ 2,502	$ (35,815)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		247
Compensation amortization under share-based plans and other changes		164
Net income	$ 3,662		3,662
Dividends			(876)
Other			(2)
Other comprehensive income (loss)	(1,309)			(1,309)
Treasury stock acquired — share repurchase authorizations					(2,156)
Net shares acquired related to employee share-based compensation plans					(44)
Balance, end of year at Dec. 31, 2021	28,887	24,154	41,555	1,193	(38,015)
Balance, beginning of year (in shares) at Dec. 31, 2020						252.4
Common shares outstanding
Treasury stock acquired — share repurchase authorization (in shares)						(13.9)
Net shares issued under employee share-based compensation plans (in shares)						2.7
Balance, end of year (in shares) at Dec. 31, 2021						241.2
Shareholders' Equity [Roll Forward]
Employee share-based compensation		227
Compensation amortization under share-based plans and other changes		184
Net income	2,842		2,842
Dividends			(880)
Other			(1)
Other comprehensive income (loss)	(7,638)			(7,638)
Treasury stock acquired — share repurchase authorizations					(2,000)
Net shares acquired related to employee share-based compensation plans	(61)				(61)
Balance, end of year at Dec. 31, 2022	$ 21,560	24,565	43,516	(6,445)	(40,076)
Common shares outstanding
Treasury stock acquired — share repurchase authorization (in shares)						(11.6)
Net shares issued under employee share-based compensation plans (in shares)						2.5
Balance, end of year (in shares) at Dec. 31, 2022	232.1					232.1
Shareholders' Equity [Roll Forward]
Employee share-based compensation		125
Compensation amortization under share-based plans and other changes		216
Net income	$ 2,991		2,991
Dividends			(915)
Other			(1)
Other comprehensive income (loss)	1,974			1,974
Treasury stock acquired — share repurchase authorizations	(965)				(965)
Net shares acquired related to employee share-based compensation plans	(64)				(64)
Balance, end of year at Dec. 31, 2023	$ 24,921	$ 24,906	$ 45,591	$ (4,471)	$ (41,105)
Common shares outstanding
Treasury stock acquired — share repurchase authorization (in shares)	(5.4)					(5.4)
Net shares issued under employee share-based compensation plans (in shares)						1.5
Balance, end of year (in shares) at Dec. 31, 2023	228.2					228.2