Consolidated Statement of Changes in Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common stock [Member]	Retained earnings [Member]	Retained earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated other comprehensive income (loss), net of tax [Member]	Treasury stock, at cost [Member]	Common shares outstanding [Member]
Shareholders' Equity [Roll Forward]
Shareholders' equity		$ 23,144	$ 35,204		$ (1,859)	$ (33,595)
Balance, beginning of year at Dec. 31, 2018		23,144	35,204		(1,859)	(33,595)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		180
Compensation amortization under share-based plans and other changes		145
Net income	$ 2,622		2,622
Dividends			(848)
Other			(1)
Other comprehensive income (loss)	2,499				2,499
Treasury stock acquired — share repurchase authorization						(1,500)
Net shares acquired related to employee share-based compensation plans						(48)
Balance, end of year at Dec. 31, 2019	25,943	23,469	36,977	$ (43)	640	(35,143)
Balance, beginning of year (in shares) at Dec. 31, 2018							263.6
Common shares outstanding
Treasury stock acquired — share repurchase authorization (in shares)							(10.8)
Net shares issued under employee share-based compensation plans (in shares)							2.7
Balance, end of year (in shares) at Dec. 31, 2019							255.5
Shareholders' Equity [Roll Forward]
Shareholders' equity	25,943	23,469	36,977	$ (43)	640	(35,143)
Employee share-based compensation		123
Compensation amortization under share-based plans and other changes		151
Net income	2,697		2,697
Dividends			(864)
Other			4
Other comprehensive income (loss)	1,862				1,862
Treasury stock acquired — share repurchase authorization						(625)
Net shares acquired related to employee share-based compensation plans	(47)					(47)
Balance, end of year at Dec. 31, 2020	$ 29,201	23,743	38,771		2,502	(35,815)
Common shares outstanding
Treasury stock acquired — share repurchase authorization (in shares)							(4.9)
Net shares issued under employee share-based compensation plans (in shares)							1.8
Balance, end of year (in shares) at Dec. 31, 2020	252.4						252.4
Shareholders' Equity [Roll Forward]
Shareholders' equity	$ 29,201	23,743	38,771		2,502	(35,815)
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 authorization	(2,160)					(2,156)
Net shares acquired related to employee share-based compensation plans	(44)					(44)
Balance, end of year at Dec. 31, 2021	$ 28,887	24,154	41,555		1,193	(38,015)
Common shares outstanding
Treasury stock acquired — share repurchase authorization (in shares)	(13.9)						(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						241.2
Shareholders' Equity [Roll Forward]
Shareholders' equity	$ 28,887	$ 24,154	$ 41,555		$ 1,193	$ (38,015)