Reserve for Future Policy Benefits and Contractholder Funds - Reserve for future policy benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reserve for life-contingent benefits:
Reserve for future policy benefits	$ 1,273	$ 1,028
Traditional life insurance and other
Reserve for life-contingent benefits:
Reserve for future policy benefits	$ 313	299
Traditional life insurance and other | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	1.80%
Traditional life insurance and other | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	7.00%
Accident and health insurance
Reserve for life-contingent benefits:
Reserve for future policy benefits	$ 960	$ 729
Accident and health insurance | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	2.80%
Accident and health insurance | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	7.00%