INVESTMENTS - Commercial Mortgage Loans by Key Credit Quality Indicators (Details) - Commercial mortgage loans $ in Millions	Jun. 30, 2021 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 200
2020	48
2019	649
2018	169
2017	68
Prior	743
Total Financing Receivable	$ 1,877
Weighted Average Debt Service Coverage Ratio	2.35
2021
Financing Receivable, Credit Quality Indicator [Line Items]
Weighted Average Debt Service Coverage Ratio	2.56
2020
Financing Receivable, Credit Quality Indicator [Line Items]
Weighted Average Debt Service Coverage Ratio	1.97
2019
Financing Receivable, Credit Quality Indicator [Line Items]
Weighted Average Debt Service Coverage Ratio	2.48
2018
Financing Receivable, Credit Quality Indicator [Line Items]
Weighted Average Debt Service Coverage Ratio	2.18
2017
Financing Receivable, Credit Quality Indicator [Line Items]
Weighted Average Debt Service Coverage Ratio	2.51
Prior
Financing Receivable, Credit Quality Indicator [Line Items]
Weighted Average Debt Service Coverage Ratio	2.23
Loan to Value Ratio, Zero to Fifty-nine Point Nine-nine Percent
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 166
2020	32
2019	439
2018	129
2017	68
Prior	569
Total Financing Receivable	$ 1,403
Weighted Average Debt Service Coverage Ratio	2.48
Loan to Value Ratio, Sixty to Sixty-nine Point Nine-nine Percent
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 34
2020	16
2019	178
2018	40
2017	0
Prior	127
Total Financing Receivable	$ 395
Weighted Average Debt Service Coverage Ratio	2.04
Loan to Value Ratio, Seventy to Seventy-nine Point Nine-nine Percent
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 0
2020	0
2019	32
2018	0
2017	0
Prior	21
Total Financing Receivable	$ 53
Weighted Average Debt Service Coverage Ratio	1.61
Loan-to-Value Ratio Eighty Percent and Above
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 0
2020	0
2019	0
2018	0
2017	0
Prior	26
Total Financing Receivable	$ 26
Weighted Average Debt Service Coverage Ratio	1.63

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