Adoption Of ASU 2018-12 (Summary Of Restated Consolidated Statements Of Stockholders Equity) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2021
Balance			$ 5,102
Net income (loss)	$ 853	$ (1,776)	483	$ 545
Other comprehensive income (loss), net of tax	(3,376)	(4,660)	(2,128)	(16,924)
Balance	3,199	2,783	3,199	2,783
Retained Earnings [Member]
Balance	5,362	7,065	5,924	5,196
Net income (loss)	853	(1,776)	483	545
Balance	6,102	5,189	6,102	5,189	$ 5,196
Retirement of common stock/cancellation of shares		(23)		(319)
Common stock dividends declared	(79)	(77)	(234)	(233)
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	(5,104)	(2,280)	(6,352)	9,984
Other comprehensive income (loss), net of tax	(3,376)	(4,660)	(2,128)	(16,924)	9,984
Balance	$ (8,480)	(6,940)	(8,480)	(6,940)	9,984
Accounting Standards Update 2018-12 [Member]
Net income (loss)		(1,776)
Other comprehensive income (loss), net of tax		(4,660)
Balance		2,783		2,783
Accounting Standards Update 2018-12 [Member] | Retained Earnings [Member]
Balance		7,065
Net income (loss)		(1,776)
Balance		5,189		5,189
Accounting Standards Update 2018-12 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Balance		(2,280)
Other comprehensive income (loss), net of tax		(4,660)
Balance		(6,940)		(6,940)
Accounting Standards Update 2018-12 [Member] | As Previously Reported [Member]
Balance			4,569
Net income (loss)		(2,583)		(2,264)
Other comprehensive income (loss), net of tax		(4,291)		(15,069)
Balance		2,668		2,668
Accounting Standards Update 2018-12 [Member] | As Previously Reported [Member] | Retained Earnings [Member]
Balance		9,445		9,578
Net income (loss)		(2,583)		(2,264)
Balance		6,762		6,762	9,578
Accounting Standards Update 2018-12 [Member] | As Previously Reported [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Balance		(4,337)
Other comprehensive income (loss), net of tax		(4,291)		(15,069)	6,441
Balance		(8,628)		(8,628)
Accounting Standards Update 2018-12 [Member] | Restatement Impacts [Member]
Balance			$ 533
Net income (loss)		807		2,809
Other comprehensive income (loss), net of tax		(369)		(1,855)
Balance		115		115
Accounting Standards Update 2018-12 [Member] | Restatement Impacts [Member] | Retained Earnings [Member]
Balance		(2,380)		(4,382)
Net income (loss)		807		2,809
Balance		(1,573)		(1,573)	(4,382)
Accounting Standards Update 2018-12 [Member] | Restatement Impacts [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Balance		2,057
Other comprehensive income (loss), net of tax		(369)		(1,855)	$ 3,543
Balance		$ 1,688		$ 1,688