Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance as of beginning-of-period at Dec. 31, 2022		$ 986	$ 4,544	$ 5,924	$ (6,352)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation/issued for benefit plans			31
Net income (loss)	$ (370)			(370)
Preferred stock dividends declared				(36)
Common stock dividends declared				(156)
Other comprehensive income (loss), net of tax	1,248				1,248
Balance as of end-of-period at Jun. 30, 2023	5,819	986	4,575	5,362	(5,104)
Balance as of beginning-of-period at Mar. 31, 2023		986	4,560	4,940	(3,754)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation/issued for benefit plans			15
Net income (loss)	511			511
Preferred stock dividends declared				(11)
Common stock dividends declared				(78)
Other comprehensive income (loss), net of tax	(1,350)				(1,350)
Balance as of end-of-period at Jun. 30, 2023	5,819	986	4,575	5,362	(5,104)
Balance as of beginning-of-period at Dec. 31, 2023	6,893	986	4,605	4,778	(3,476)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation/issued for benefit plans			36
Net income (loss)	2,116			2,116
Preferred stock dividends declared				(46)
Common stock dividends declared				(157)
Other comprehensive income (loss), net of tax	(893)				(893)
Balance as of end-of-period at Jun. 30, 2024	7,949	986	4,641	6,691	(4,369)
Balance as of beginning-of-period at Mar. 31, 2024		986	4,624	5,887	(3,951)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation/issued for benefit plans			17
Net income (loss)	895			895
Preferred stock dividends declared				(11)
Common stock dividends declared				(80)
Other comprehensive income (loss), net of tax	(418)				(418)
Balance as of end-of-period at Jun. 30, 2024	$ 7,949	$ 986	$ 4,641	$ 6,691	$ (4,369)