Consolidated Statements Of Stockholders' Equity - USD ($) $ in Millions	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Other comprehensive income (loss), net of tax				$ 9,984
Balance at Dec. 31, 2021		$ 4,735	$ 5,196	9,984
Stock compensation/issued for benefit plans		30
Net income (loss)			545		$ 545
Retirement of common stock/cancellation of shares		(231)	(319)
Common stock dividends declared			(233)
Other comprehensive income (loss), net of tax				(16,924)	(16,924)
Balance at Sep. 30, 2022		4,534	5,189	(6,940)	2,783
Balance at Jun. 30, 2022		4,546	7,065	(2,280)
Stock compensation/issued for benefit plans		15
Net income (loss)			(1,776)		(1,776)
Retirement of common stock/cancellation of shares		(27)	(23)
Common stock dividends declared			(77)
Other comprehensive income (loss), net of tax				(4,660)	(4,660)
Balance at Sep. 30, 2022		4,534	5,189	(6,940)	2,783
Balance at Dec. 31, 2022	$ 986	4,544	5,924	(6,352)	5,102
Stock compensation/issued for benefit plans		47
Net income (loss)			483		483
Preferred stock dividends declared			(71)
Common stock dividends declared			(234)
Other comprehensive income (loss), net of tax				(2,128)	(2,128)
Balance at Sep. 30, 2023	986	4,591	6,102	(8,480)	3,199
Balance at Jun. 30, 2023	986	4,575	5,362	(5,104)
Stock compensation/issued for benefit plans		16
Net income (loss)			853		853
Preferred stock dividends declared			(34)
Common stock dividends declared			(79)
Other comprehensive income (loss), net of tax				(3,376)	(3,376)
Balance at Sep. 30, 2023	$ 986	$ 4,591	$ 6,102	$ (8,480)	$ 3,199