INVESTMENTS - Middle Market Loans by Key Credit Quality Indicators (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 12,592	$ 12,801
Middle market loans
Financing Receivable, Credit Quality Indicator [Line Items]
2024	66
2023	130
2022	591
2021	1,128
2020	658
Prior	1,136
Revolving Loans	877
Total	4,586	$ 4,677
2024	0
2023	0
2022	0
2021	27
2020	0
Prior	23
Revolving Loans	0
Total	50
Middle market loans | BBB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	17
2022	45
2021	123
2020	54
Prior	64
Revolving Loans	77
Total	380
Middle market loans | BB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	18
2023	60
2022	308
2021	408
2020	251
Prior	287
Revolving Loans	446
Total	1,778
Middle market loans | B Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	48
2023	53
2022	218
2021	547
2020	302
Prior	633
Revolving Loans	290
Total	2,091
Middle market loans | CCC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	20
2021	50
2020	51
Prior	136
Revolving Loans	48
Total	305
Middle market loans | CC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	0
2021	0
2020	0
Prior	10
Revolving Loans	0
Total	10
Middle market loans | C and Lower Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	0
2021	0
2020	0
Prior	6
Revolving Loans	16
Total	$ 22