Investments - Mortgage Loans, Residential by State (Details) - Geographic Concentration Risk - Residential mortgage loans - Mortgage Loans, Net	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	100.00%	100.00%
California
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	28.50%	28.90%
Florida
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	10.10%	9.70%
NEW YORK
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	5.80%	5.60%
Other U.S. States
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	32.80%	31.70%
Total U.S. Region
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	87.60%	86.30%
IRELAND
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	5.00%
UNITED KINGDOM
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk		5.40%
Other
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	7.40%	8.30%
International
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	12.40%	13.70%
NEW JERSEY
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	5.40%	5.30%
ARIZONA
Loans and Leases Receivable Disclosure [Line Items]
Percentage concentration risk	5.00%	5.10%