INSURANCE LIABILITIES - Fair Values of GMxB and Other Derivative Liability (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Embedded and freestanding derivative liability	$ 5,862				$ 6,206
Guaranteed minimum income benefit reinsurance asset, at fair value	10,488	$ 10,900	$ 11,260	$ 9,798	10,314
GMIBNLG
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Embedded and freestanding derivative liability	4,056				5,155
SCS, SIO, MSO and IUL indexed features’ liability
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Embedded and freestanding derivative liability	1,698				887
GWBL/GMWB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Embedded and freestanding derivative liability	130				114
GIB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Embedded and freestanding derivative liability	(27)				30
GMAB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Embedded and freestanding derivative liability	5				20
GMIB reinsurance contracts
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Guaranteed minimum income benefit reinsurance asset, at fair value	$ 10,488				$ 10,314