CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock, at Cost	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2019			2,000,000	433,000,000
Beginning balance at Dec. 31, 2019	$ 22,201	$ (331)	$ 1,570	$ 6	$ 18,891	$ 6,498	$ (331)	$ (4,353)	$ (411)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(672)					(672)
Dividends to preferred stockholders	(107)					(107)
Preferred stock issued	395		$ 395
Treasury stock purchased (in shares)				(8,000,000)
Treasury stock purchased	(270)							(270)
Share-based compensation plans (in shares)				1,000,000
Share-based compensation plans	30				30
Employee stock purchase plan (in shares)				1,000,000
Employee stock purchase plan	19				19
Total comprehensive income (loss):
Net income	1,057					1,057
Other comprehensive income (loss)	351								351
Total comprehensive income (loss)	1,408					1,057			351
Ending balance (in shares) at Dec. 31, 2020			2,000,000	427,000,000
Ending balance at Dec. 31, 2020	22,673		$ 1,965	$ 6	18,940	6,445		(4,623)	(60)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(670)					(670)
Dividends to preferred stockholders	(113)					(113)
Preferred stock issued	296		296
Preferred stock redemption	$ (250)		$ (247)			(3)
Treasury stock purchased (in shares)	(6,455,636)			(6,000,000)
Treasury stock purchased	$ (295)							(295)
Share-based compensation plans (in shares)				1,000,000
Share-based compensation plans	43				43
Employee stock purchase plan	22				22
Total comprehensive income (loss):
Net income	2,319					2,319
Other comprehensive income (loss)	(605)								(605)
Total comprehensive income (loss)	1,714					2,319			(605)
Ending balance (in shares) at Dec. 31, 2021			2,000,000	422,000,000
Ending balance at Dec. 31, 2021	23,420		$ 2,014	$ 6	19,005	7,978		(4,918)	(665)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(779)					(779)
Dividends to preferred stockholders	(113)					(113)
Issuance of common stock - business acquisition (in shares)				72,000,000
Issuance of common stock - business acquisition	$ 3,036				3,036
Treasury stock purchased (in shares)	(3,815,922)			(4,000,000)
Treasury stock purchased	$ (153)							(153)
Share-based compensation plans (in shares)				2,000,000
Share-based compensation plans	77				77
Employee stock purchase plan	24				24
Total comprehensive income (loss):
Net income	2,073					2,073
Other comprehensive income (loss)	(3,895)								(3,895)
Total comprehensive income (loss)	(1,822)					2,073			(3,895)
Ending balance (in shares) at Dec. 31, 2022			2,000,000	492,000,000
Ending balance at Dec. 31, 2022	$ 23,690		$ 2,014	$ 6	$ 22,142	$ 9,159		$ (5,071)	$ (4,560)