Reinsurance (Consolidated Reinsurance) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Premiums written [Abstract]
Direct	$ 56,867	$ 52,969	$ 47,511
Assumed	5,136	4,557	4,467
Ceded	(10,535)	(10,165)	(10,258)
Net	51,468	47,361	41,720
Premiums earned [Abstract]
Direct	55,148	51,582	46,160
Assumed	4,970	4,289	4,395
Ceded	(10,272)	(10,159)	(10,195)
Net premiums earned	49,846	45,712	40,360
Policyholder Benefits and Claims Incurred, Ceded	$ 6,500	$ 7,200	$ 6,900