INVESTMENTS - Middle Market Loans by Key Credit Quality Indicators (Details) - Middle market loans $ in Millions	Jun. 30, 2021 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 493
2020	956
2019	1,109
2018	697
2017	405
Prior	217
Revolving Loans	461
Total Financing Receivable	4,338
BBB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2021	18
2020	84
2019	58
2018	39
2017	10
Prior	3
Revolving Loans	48
Total Financing Receivable	260
BB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2021	146
2020	358
2019	310
2018	202
2017	66
Prior	32
Revolving Loans	161
Total Financing Receivable	1,275
B Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2021	329
2020	501
2019	660
2018	361
2017	223
Prior	148
Revolving Loans	177
Total Financing Receivable	2,399
CCC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	5
2019	81
2018	81
2017	67
Prior	34
Revolving Loans	72
Total Financing Receivable	340
CC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	14
2017	39
Prior	0
Revolving Loans	2
Total Financing Receivable	55
C and Lower Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	8
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	1
Total Financing Receivable	$ 9