Investments - Schedule of Principal Geographic Distribution of Municipal Bond Issuers Exceeding 5% of the Portfolio (Details)	Dec. 31, 2023	Dec. 31, 2022
Texas
Municipal Bonds
Percentage of municipal bond portfolio carrying value	12.80%	9.60%
California
Municipal Bonds
Percentage of municipal bond portfolio carrying value	7.70%	8.50%
New York
Municipal Bonds
Percentage of municipal bond portfolio carrying value	6.30%	6.70%
Illinois
Municipal Bonds
Percentage of municipal bond portfolio carrying value	5.40%	5.60%
Pennsylvania
Municipal Bonds
Percentage of municipal bond portfolio carrying value	5.40%	5.40%
Florida
Municipal Bonds
Percentage of municipal bond portfolio carrying value	4.80%	5.00%