Financing Receivables - Credit Quality - Commercial Mortgage Loans by Property Type (Details) - Commercial Loans - Commercial mortgage loans - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Concentrations of credit risk by property type
Loans	$ 1,837	$ 1,832
Apartments
Concentrations of credit risk by property type
Loans	483	485
Hotel
Concentrations of credit risk by property type
Loans	19	13
Industrial
Concentrations of credit risk by property type
Loans	313	317
Mixed use
Concentrations of credit risk by property type
Loans	64	64
Office
Concentrations of credit risk by property type
Loans	233	241
Retail
Concentrations of credit risk by property type
Loans	573	561
Other
Concentrations of credit risk by property type
Loans	$ 152	$ 151
Total commercial mortgage loans | Credit concentration risk
Concentrations of credit risk by property type
Percentage of total	100.00%	100.00%
Total commercial mortgage loans | Credit concentration risk | Apartments
Concentrations of credit risk by property type
Percentage of total	26.00%	26.00%
Total commercial mortgage loans | Credit concentration risk | Hotel
Concentrations of credit risk by property type
Percentage of total	1.00%	1.00%
Total commercial mortgage loans | Credit concentration risk | Industrial
Concentrations of credit risk by property type
Percentage of total	17.00%	17.00%
Total commercial mortgage loans | Credit concentration risk | Mixed use
Concentrations of credit risk by property type
Percentage of total	4.00%	4.00%
Total commercial mortgage loans | Credit concentration risk | Office
Concentrations of credit risk by property type
Percentage of total	13.00%	13.00%
Total commercial mortgage loans | Credit concentration risk | Retail
Concentrations of credit risk by property type
Percentage of total	31.00%	31.00%
Total commercial mortgage loans | Credit concentration risk | Other
Concentrations of credit risk by property type
Percentage of total	8.00%	8.00%