Reinsurance (Summary Of Direct, Assumed And Ceded Premiums Earned) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reinsurance Disclosures [Abstract]
Direct - Premiums earned	$ 128,867	$ 113,149	$ 100,832
Assumed - Premium earned	4,426	4,298	3,356
Ceded - Premium earned	(64)	(74)	(79)
Premiums	$ 133,229	$ 117,373	$ 104,109
Percentage - assumed to net premiums - earned	3.30%	3.70%	3.20%