Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Series C Preferred Stock	Series D Preferred Stock	Preferred Stock	Preferred Stock Series C Preferred Stock	Preferred Stock Series D Preferred Stock	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance as of beginning-of-year at Dec. 31, 2021				$ 0			$ 4,735	$ 5,196	$ 9,984
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preferred stock					$ 493	$ 493
Stock compensation/issued for benefit plans							40
Net income (loss)	$ 1,358							1,358
Retirement of common stock/cancellation of shares							(231)	(319)
Common stock dividends declared								(311)
Other comprehensive income (loss), net of tax	(16,336)								(16,336)
Balance as of end-of-year at Dec. 31, 2022	5,102			986			4,544	5,924	(6,352)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation/issued for benefit plans							61
Net income (loss)	(752)							(752)
Preferred stock dividends declared	(82)	$ (36)	$ (46)					(82)
Common stock dividends declared								(312)
Other comprehensive income (loss), net of tax	2,876								2,876
Balance as of end-of-year 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							69
Net income (loss)	3,275							3,275
Preferred stock dividends declared	(91)	$ (46)	$ (45)					(91)
Common stock dividends declared								(317)
Other comprehensive income (loss), net of tax	(1,560)								(1,560)
Balance as of end-of-year at Dec. 31, 2024	$ 8,269			$ 986			$ 4,674	$ 7,645	$ (5,036)