Consolidated Statements Of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock, Common	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance – beginning of period, net of tax at Dec. 31, 2021		$ 10,985	$ (7,464)	$ 8,478	$ 47,403	$ (1,074)
CB_Par value reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		(319)	2,510		(2,191)
Common Shares repurchased			(2,130)
Net shares issued under employee share-based compensation plans			290	(195)
Exercise of stock options				(27)
Share-based compensation expense				139
Funding of dividends declared to Retained earnings				(688)
Net income (loss)	$ 3,143				3,143
Funding of dividends declared from Additional paid-in capital					688
Dividends declared on Common Shares					(688)
Other Comprehensive Income (Loss), Net of Tax	(7,592)					(7,592)
Balance – end of period, net of tax at Jun. 30, 2022	51,268	10,666	(6,794)	7,707	48,355	(8,666)
Balance – beginning of period, net of tax at Mar. 31, 2022		10,666	(5,700)	7,988	47,165	(4,403)
CB_Par value reduction		0		0
Treasury Stock, Retired, Cost Method, Amount		0	0		0
Common Shares repurchased			(1,129)
Net shares issued under employee share-based compensation plans			35	4
Exercise of stock options				(6)
Share-based compensation expense				69
Funding of dividends declared to Retained earnings				(348)
Net income (loss)	1,190				1,190
Funding of dividends declared from Additional paid-in capital					348
Dividends declared on Common Shares					(348)
Other Comprehensive Income (Loss), Net of Tax	(4,263)					(4,263)
Balance – end of period, net of tax at Jun. 30, 2022	51,268	10,666	(6,794)	7,707	48,355	(8,666)
Balance – beginning of period, net of tax at Dec. 31, 2022	50,519	10,346	(5,113)	7,166	48,305	(10,185)
CB_Par value reduction		(9,759)		9,759
Treasury Stock, Retired, Cost Method, Amount		(346)	2,869		(2,523)
Common Shares repurchased			(1,152)
Net shares issued under employee share-based compensation plans			222	(206)
Exercise of stock options				(13)
Share-based compensation expense				155
Funding of dividends declared to Retained earnings				(698)
Net income (loss)	3,685				3,685
Funding of dividends declared from Additional paid-in capital					698
Dividends declared on Common Shares					(698)
Other Comprehensive Income (Loss), Net of Tax	363					363
Balance – end of period, net of tax at Jun. 30, 2023	52,875	241	(3,174)	16,163	49,467	(9,822)
Balance – beginning of period, net of tax at Mar. 31, 2023		10,346	(5,341)	6,680	50,197	(8,895)
CB_Par value reduction		(9,759)		9,759
Treasury Stock, Retired, Cost Method, Amount		(346)	2,869		(2,523)
Common Shares repurchased			(724)
Net shares issued under employee share-based compensation plans			22	5
Exercise of stock options				0
Share-based compensation expense				73
Funding of dividends declared to Retained earnings				(354)
Net income (loss)	1,793				1,793
Funding of dividends declared from Additional paid-in capital					354
Dividends declared on Common Shares					(354)
Other Comprehensive Income (Loss), Net of Tax	(927)					(927)
Balance – end of period, net of tax at Jun. 30, 2023	$ 52,875	$ 241	$ (3,174)	$ 16,163	$ 49,467	$ (9,822)