Investments - Concentration of Credit Risk (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Fair Value, Concentration of Risk, Investments	$ 0	$ 0
Residential Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Largest exposure by sector, percent of invested assets	8.00%	7.00%
Financial Services Sector [Member]
Schedule of Investments [Line Items]
Largest exposure by sector, percent of invested assets	9.00%	9.00%
Debt Security, Corporate, US | hig_Next Era Energy Inc
Schedule of Investments [Line Items]
Largest exposure by issuer, percent of invested assets (less than)	1.00%
Debt Security, Corporate, US | Toronto Dominion Bank
Schedule of Investments [Line Items]
Largest exposure by issuer, percent of invested assets (less than)		1.00%
Debt Security, Corporate, US | Morgan Stanley
Schedule of Investments [Line Items]
Largest exposure by issuer, percent of invested assets (less than)	1.00%	1.00%
Debt Security, Corporate, US | Mitsubishi UFJ Financial Group
Schedule of Investments [Line Items]
Largest exposure by issuer, percent of invested assets (less than)		1.00%
Municipal
Schedule of Investments [Line Items]
Largest exposure by sector, percent of invested assets	11.00%	12.00%
Debt Security, Government, Non-US [Member] | Government of Canada
Schedule of Investments [Line Items]
Largest exposure by issuer, percent of invested assets (less than)	1.00%