FAIR VALUE DISCLOSURES - UNREALIZED GAINS (LOSSES) FOR LEVEL 3 STILL HELD (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	$ 87	$ (11)
Level 3 | Corporate
Change in Accounting Estimate [Line Items]
Net Derivative Gains (losses)	0	0
OCI	(20)	45
Level 3 | States and political subdivisions
Change in Accounting Estimate [Line Items]
Net Derivative Gains (losses)	0	0
OCI	(1)	0
Level 3 | Commercial mortgage-backed
Change in Accounting Estimate [Line Items]
Net Derivative Gains (losses)	0	31
OCI	0	12
Level 3 | Asset-backed
Change in Accounting Estimate [Line Items]
Net Derivative Gains (losses)	0	0
OCI	0	4
Level 3 | GMIB reinsurance contracts
Change in Accounting Estimate [Line Items]
Net Derivative Gains (losses)	0	0
OCI	0	0
Level 3 | Separate Account assets
Change in Accounting Estimate [Line Items]
Net Derivative Gains (losses)	7	10
OCI	0	0
Level 3 | Assets and Liabilities Still Held | Corporate
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0	0
Net Derivative Gains (losses)	0	0
OCI	(19)	41
Level 3 | Assets and Liabilities Still Held | States and political subdivisions
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0
Net Derivative Gains (losses)	0
OCI	(1)
Level 3 | Assets and Liabilities Still Held | Commercial mortgage-backed
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0	0
Net Derivative Gains (losses)	0	0
OCI	0	12
Level 3 | Assets and Liabilities Still Held | Asset-backed
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0	0
Net Derivative Gains (losses)	0	0
OCI	0	4
Level 3 | Assets and Liabilities Still Held | Subtotal
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0	0
Net Derivative Gains (losses)	0	0
OCI	(20)	57
Level 3 | Assets and Liabilities Still Held | GMIB reinsurance contracts
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0	0
Net Derivative Gains (losses)	(842)	(533)
OCI	0	0
Level 3 | Assets and Liabilities Still Held | Separate Account assets
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	7	10
Net Derivative Gains (losses)	0	0
OCI	0	0
Level 3 | Assets and Liabilities Still Held | GMxB derivative features' liability
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	0	0
Net Derivative Gains (losses)	440	490
OCI	0	0
Level 3 | Assets and Liabilities Still Held | Total
Change in Accounting Estimate [Line Items]
Investment Gains (Losses), Net	7	10
Net Derivative Gains (losses)	(402)	(43)
OCI	$ (20)	$ 57