v3.24.0.1
Reinsurance - Supplemental information for loss and benefit reserves, gross and net of ceded reinsurance (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Jan. 01, 2021
Dec. 31, 2020
As Reported          
Liability for unpaid losses and loss adjustment expenses $ (70,393) $ (75,167) $ (79,026)   $ (77,720)
Future policy benefits for life and accident and health insurance contracts (58,576) (51,914)   $ (67,364)  
Policyholder contract deposits (161,979) (155,984)   (148,223)  
Unearned premiums (17,387) (18,338)      
Other policyholder funds (3,356) (3,463)   $ (3,796)  
Reinsurance assets 62,587 64,810      
Net of Reinsurance          
Liability for unpaid losses and loss adjustment expenses (39,994) (42,955)      
Future policy benefits for life and accident and health insurance contracts (35,005) (27,836)      
Policyholder contract deposits (158,171) (152,375)      
Reserve for unearned premiums (13,117) (13,992)      
Other policyholder funds (2,817) (2,898)      
Reinsurance asset, allowance for credit loss 236 295      
Reserve for liability to unpaid losses 110 110      
Recoveries of amounts previously written off 0 2      
Loss Recoveries          
Effects of Reinsurance [Line Items]          
Contract claim recoverables 4,879 4,662      
Contract Claims Recoverable          
Effects of Reinsurance [Line Items]          
Contract claim recoverables $ 296 $ 545