INVESTMENTS - Middle Market Loans by Key Credit Quality Indicators (Details) - Middle market loans $ in Millions	Jun. 30, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 393
2019	1,206
2018	724
2017	510
2016	196
Prior	82
Revolving Loans	415
Total Financing Receivable	3,526
BBB
Financing Receivable, Credit Quality Indicator [Line Items]
2020	38
2019	121
2018	57
2017	57
2016	13
Prior	0
Revolving Loans	24
Total Financing Receivable	310
BB
Financing Receivable, Credit Quality Indicator [Line Items]
2020	150
2019	214
2018	235
2017	90
2016	30
Prior	24
Revolving Loans	80
Total Financing Receivable	823
B
Financing Receivable, Credit Quality Indicator [Line Items]
2020	184
2019	767
2018	303
2017	266
2016	120
Prior	41
Revolving Loans	219
Total Financing Receivable	1,900
CCC
Financing Receivable, Credit Quality Indicator [Line Items]
2020	21
2019	103
2018	129
2017	58
2016	33
Prior	17
Revolving Loans	90
Total Financing Receivable	451
CC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	1
2018	0
2017	39
2016	0
Prior	0
Revolving Loans	2
Total Financing Receivable	$ 42