CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - 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, 2021			2,000,000	422,000,000
Beginning 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	(165)					(165)
Dividends to preferred stockholders	(24)					(24)
Share-based compensation plans (in shares)				1,000,000
Share-based compensation plans	10				10
Employee stock purchase plan	6				6
Total comprehensive income (loss):
Net income	420					420
Other comprehensive income (loss)	(1,593)								(1,593)
Total comprehensive income (loss)	(1,173)					420			(1,593)
Ending balance (in shares) at Mar. 31, 2022			2,000,000	423,000,000
Ending balance at Mar. 31, 2022	22,074		$ 2,014	$ 6	19,021	8,209		(4,918)	(2,258)
Beginning balance (in shares) at Dec. 31, 2022			2,000,000	492,000,000
Beginning balance at Dec. 31, 2022	23,690	$ (26)	$ 2,014	$ 6	22,142	9,159	$ (26)	(5,071)	(4,560)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(205)					(205)
Dividends to preferred stockholders	$ (23)					(23)
Treasury stock purchased (in shares)	(10,089,291)			(10,000,000)
Treasury stock purchased	$ (400)							(400)
Share repurchase excise tax	(4)							(4)
Share-based compensation plans (in shares)				2,000,000
Share-based compensation plans	33				33
Employee stock purchase plan	8				8
Total comprehensive income (loss):
Net income	511					511
Other comprehensive income (loss)	617								617
Total comprehensive income (loss)	1,128					511			617
Ending balance (in shares) at Mar. 31, 2023			2,000,000	484,000,000
Ending balance at Mar. 31, 2023	$ 24,201		$ 2,014	$ 6	$ 22,183	$ 9,416		$ (5,475)	$ (3,943)