Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Balance Sheets) (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash	$ 475	$ 536
Total assets	60,927	66,639
Liabilities
Short term debt	243	0
Long term debt	2,538	2,779
Other liabilities	2,983	3,377
Total liabilities	52,102	53,830
Stockholders' Equity
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 270,895,902 and 271,363,999 shares outstanding)	683	683
Additional paid-in capital	2,220	2,215
Retained earnings	9,572	9,663
Accumulated other comprehensive (loss) income	(3,557)	320
Treasury stock (2,144,341 and 1,676,244 shares), at cost	(93)	(72)
Total stockholders’ equity	8,825	12,809	$ 12,707
Total liabilities and stockholders' equity	$ 60,927	$ 66,639
Balance Sheet Parenthetical
Common stock, par value (in usd per share)	$ 2.50	$ 2.50
Common stock, shares authorized (in shares	500,000,000	500,000,000
Common stock, shares issued (in shares)	273,040,243	273,040,243
Common stock, shares outstanding (in shares)	270,895,902	271,363,999
Treasury stock, shares (in shares)	2,144,341	1,676,244
Parent Company
Assets
Investment in subsidiaries	$ 11,063	$ 14,937
Cash	2	1
Short term investments	578	685
Amounts due from affiliates	4	3
Total assets	11,647	15,626
Liabilities
Short term debt	243	0
Long term debt	2,538	2,779
Other liabilities	41	38
Total liabilities	2,822	2,817
Stockholders' Equity
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 270,895,902 and 271,363,999 shares outstanding)	683	683
Additional paid-in capital	2,220	2,215
Retained earnings	9,572	9,663
Accumulated other comprehensive (loss) income	(3,557)	320
Treasury stock (2,144,341 and 1,676,244 shares), at cost	(93)	(72)
Total stockholders’ equity	8,825	12,809
Total liabilities and stockholders' equity	$ 11,647	$ 15,626