Fair Value of Assets and Liabilities - Carrying values and fair value estimates of financial instruments not carried at fair value (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Financial assets
Mortgage loans	$ 848	$ 821
Financial liabilities
Long-term debt	7,970	7,976
Liability for collateral	2,032	1,444	$ 1,495	$ 914
Significant unobservable inputs (Level 3) | Amortized cost, net
Financial assets
Mortgage loans	848	821
Bank loans	868	1,574
Financial liabilities
Contractholder funds on investment contracts	53	55
Significant unobservable inputs (Level 3) | Fair value
Financial assets
Mortgage loans	821	853
Bank loans	847	1,634
Financial liabilities
Contractholder funds on investment contracts	53	55
Significant other observable inputs (Level 2) | Amortized cost, net
Financial liabilities
Long-term debt	7,970	7,976
Liability for collateral	2,032	1,444
Significant other observable inputs (Level 2) | Fair value
Financial liabilities
Long-term debt	7,711	9,150
Liability for collateral	$ 2,032	$ 1,444