INVESTMENTS - Middle Market Loans by Key Credit Quality Indicators (Details) - Middle market loans $ in Millions	Dec. 31, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 891
2019	1,022
2018	702
2017	473
2016	202
Prior	65
Revolving Loans	365
Total Financing Receivable	3,720
BBB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	36
2019	71
2018	51
2017	33
2016	4
Prior	0
Revolving Loans	20
Total Financing Receivable	215
BB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	269
2019	247
2018	211
2017	93
2016	37
Prior	15
Revolving Loans	90
Total Financing Receivable	962
B Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	483
2019	615
2018	325
2017	219
2016	127
Prior	23
Revolving Loans	170
Total Financing Receivable	1,962
CCC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	95
2019	89
2018	97
2017	89
2016	31
Prior	27
Revolving Loans	84
Total Financing Receivable	512
CC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	39
2016	3
Prior	0
Revolving Loans	1
Total Financing Receivable	43
C and Lower Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	8
2019	0
2018	18
2017	0
2016	0
Prior	0
Revolving Loans	0
Total Financing Receivable	$ 26