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, 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
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
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)
Beginning balance (in shares) at Dec. 31, 2023			2,000,000	466,000,000
Beginning balance at Dec. 31, 2023	24,342		$ 2,014	$ 6	22,250	9,816		(5,986)	(3,758)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(197)					(197)
Dividends to preferred stockholders	$ (30)					(30)
Treasury stock purchased (in shares)	(9,244,939)			(9,000,000)
Treasury stock purchased	$ (300)							(300)
Share repurchase excise tax	(4)							(4)
Share-based compensation plans (in shares)				1,000,000
Share-based compensation plans	15				15
Employee stock purchase plan	7				7
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income	334					334
Other comprehensive income (loss)	(406)								(406)
Total comprehensive income (loss)	(72)					334			(406)
Ending balance (in shares) at Mar. 31, 2024			2,000,000	458,000,000
Ending balance at Mar. 31, 2024	$ 23,761		$ 2,014	$ 6	$ 22,272	$ 9,923		$ (6,290)	$ (4,164)