Equity Securities - Equity Securities by Market Sector Distribution (Details) - Equity securities - Industry sector	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Percentage	100.00%	100.00%
Energy and utilities
Debt and Equity Securities, FV-NI [Line Items]
Percentage	33.00%	30.00%
Finance
Debt and Equity Securities, FV-NI [Line Items]
Percentage	22.00%	24.00%
Healthcare
Debt and Equity Securities, FV-NI [Line Items]
Percentage	7.00%	9.00%
Industrials
Debt and Equity Securities, FV-NI [Line Items]
Percentage	4.00%	3.00%
Information technology
Debt and Equity Securities, FV-NI [Line Items]
Percentage	25.00%	18.00%
Other
Debt and Equity Securities, FV-NI [Line Items]
Percentage	9.00%	16.00%