INSURANCE LIABILITIES - Variable Annuity Contracts with GMDB and GMIB Features (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
GMDB
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 14,214
Account Value Invested In Separate Accounts	92,504	$ 94,672
Net amount at risk, gross	18,707
Net amount at risk, net of amounts reinsured	$ 8,562
Average attained age of contract holders	55 years 2 months 12 days
Percentage of contract holders over age 70	18.30%
GMDB | Minimum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	3.00%
GMDB | Maximum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	6.50%
GMDB | Return of Premium
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 13,848
Account Value Invested In Separate Accounts	45,136
Net amount at risk, gross	186
Net amount at risk, net of amounts reinsured	$ 186
Average attained age of contract holders	52 years
Percentage of contract holders over age 70	9.70%
GMDB | Ratchet
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 107
Account Value Invested In Separate Accounts	9,319
Net amount at risk, gross	117
Net amount at risk, net of amounts reinsured	$ 87
Average attained age of contract holders	67 years
Percentage of contract holders over age 70	40.90%
GMDB | Roll-Up
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 64
Account Value Invested In Separate Accounts	3,381
Net amount at risk, gross	2,016
Net amount at risk, net of amounts reinsured	$ 1,378
Average attained age of contract holders	73 years
Percentage of contract holders over age 70	63.70%
GMDB | Roll-Up | Minimum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	3.00%
GMDB | Roll-Up | Maximum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	6.00%
GMDB | Combo
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 195
Account Value Invested In Separate Accounts	34,668
Net amount at risk, gross	16,388
Net amount at risk, net of amounts reinsured	$ 6,911
Average attained age of contract holders	68 years
Percentage of contract holders over age 70	47.40%
GMDB | Combo | Minimum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	3.00%
GMDB | Combo | Maximum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	6.50%
GMIB
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 309
Account Value Invested In Separate Accounts	60,459	$ 62,286
Net amount at risk, gross	7,205
Net amount at risk, net of amounts reinsured	$ 1,828
Weighted average years remaining until annuitization	9 months 18 days
GMIB | Minimum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	3.00%
GMIB | Maximum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	6.50%
GMIB | Roll-Up
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 24
Account Value Invested In Separate Accounts	20,855
Net amount at risk, gross	883
Net amount at risk, net of amounts reinsured	$ 268
Weighted average years remaining until annuitization	1 year 8 months 12 days
GMIB | Roll-Up | Minimum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	3.00%
GMIB | Roll-Up | Maximum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	6.00%
GMIB | Combo
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 285
Account Value Invested In Separate Accounts	39,604
Net amount at risk, gross	6,322
Net amount at risk, net of amounts reinsured	$ 1,560
Weighted average years remaining until annuitization	8 months 12 days
GMIB | Combo | Minimum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	3.00%
GMIB | Combo | Maximum
Net Amount at Risk by Product and Guarantee [Line Items]
Range of contractually specified interest rates	6.50%