INVESTMENTS - Amortized Cost of Loans by Credit Quality Indicator and Origination Year (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Amortized Cost Basis by Origination Year
Total	$ 18,317	$ 18,154
Residential mortgages:
Amortized Cost Basis by Origination Year
Current fiscal year	0	98
Fiscal year before current fiscal year	277	121
Two years before current fiscal year	120	74
Three years before current fiscal year	74	2
Four years before current fiscal year	2	1
Prior	2	2
Total	475	298
Residential mortgages: | Performing
Amortized Cost Basis by Origination Year
Current fiscal year	0	98
Fiscal year before current fiscal year	277	121
Two years before current fiscal year	120	74
Three years before current fiscal year	74	2
Four years before current fiscal year	2	1
Prior	2	2
Total	475	298
Residential mortgages: | Nonperforming
Amortized Cost Basis by Origination Year
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	0
Total	$ 0	$ 0