INVESTMENTS - Mortgage Loans (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	$ 70	$ 70
Commercial Real Estate Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	62	33
Current-period provision for expected credit losses	4	33
Write-offs charged against the allowance	0	0
Recoveries of amounts previously written off	0	0
Net change in allowance	4	33
Ending balance	66	66
Agricultural Real Estate Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4	3
Current-period provision for expected credit losses	0	1
Write-offs charged against the allowance	0	0
Recoveries of amounts previously written off	0	0
Net change in allowance	0	1
Ending balance	$ 4	$ 4