Insurance Liabilities - Summary of separate accounts (Details) - Universal Life - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Account value	$ 3,721	$ 3,514
Net amount at risk	$ 72,422	$ 69,335
Average attained age of contract holders	53 years	53 years