INVESTMENTS - Transitional Real Estate Loans by Key Credit Quality Indicators (Details) - Transitional real estate loans $ in Millions	Dec. 31, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 403
2019	2,281
2018	1,792
2017	755
2016	34
Prior	29
Total Financing Receivable	5,294
Loan to Value Ratio, Zero to Fifty-nine Point Nine-nine Percent
Financing Receivable, Credit Quality Indicator [Line Items]
2020	79
2019	670
2018	397
2017	159
2016	20
Prior	29
Total Financing Receivable	1,354
Loan to Value Ratio, Sixty to Sixty-nine Point Nine-nine Percent
Financing Receivable, Credit Quality Indicator [Line Items]
2020	214
2019	857
2018	722
2017	372
2016	0
Prior	0
Total Financing Receivable	2,165
Loan to Value Ratio, Seventy to Seventy-nine Point Nine-nine Percent
Financing Receivable, Credit Quality Indicator [Line Items]
2020	84
2019	754
2018	673
2017	224
2016	14
Prior	0
Total Financing Receivable	1,749
Loan to Value Ratio Eighty Percent and Above
Financing Receivable, Credit Quality Indicator [Line Items]
2020	26
2019	0
2018	0
2017	0
2016	0
Prior	0
Total Financing Receivable	$ 26

Amount of financing receivable originated more than five years prior to current fiscal year.

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Amount of financing receivable originated four years prior to current fiscal year.

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Amount of financing receivable originated in current fiscal year.

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Amount of financing receivable originated in fiscal year prior to current fiscal year.

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Amount of financing receivable originated three years prior to current fiscal year.

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Amount of financing receivable originated two years prior to current fiscal year.

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Amount, before allowance for credit loss, of financing receivable.

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