INSURANCE LIABILITIES - VARIABLE ANNUITY CONTRACTS WITH GMDB AND GMIB FEATURES (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
GMDB
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 14,398
Account Value Invested In Separate Accounts	95,299	$ 94,672
Net amount at risk, gross	18,205
Net amount at risk, net of amounts reinsured	$ 17,615
Average attained age of policyholders	55 years 6 months
Percentage of policyholders over age 70	18.70%
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	$ 14,046
Account Value Invested In Separate Accounts	47,293
Net amount at risk, gross	162
Net amount at risk, net of amounts reinsured	$ 162
Average attained age of policyholders	51 years 7 months 6 days
Percentage of policyholders over age 70	9.90%
GMDB | Ratchet
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 102
Account Value Invested In Separate Accounts	9,522
Net amount at risk, gross	53
Net amount at risk, net of amounts reinsured	$ 50
Average attained age of policyholders	66 years 9 months 18 days
Percentage of policyholders over age 70	42.20%
GMDB | Roll-Up
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 62
Account Value Invested In Separate Accounts	3,418
Net amount at risk, gross	1,892
Net amount at risk, net of amounts reinsured	$ 1,305
Average attained age of policyholders	73 years 4 months 24 days
Percentage of policyholders over age 70	64.90%
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	$ 188
Account Value Invested In Separate Accounts	35,066
Net amount at risk, gross	16,098
Net amount at risk, net of amounts reinsured	$ 16,098
Average attained age of policyholders	68 years 9 months 18 days
Percentage of policyholders over age 70	49.10%
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	$ 295
Account Value Invested In Separate Accounts	61,278	$ 62,286
Net amount at risk, gross	6,546
Net amount at risk, net of amounts reinsured	$ 5,508
Average attained age of policyholders	69 years 2 months 12 days
Weighted average years remaining until annuitization	7 months 13 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	$ 21
Account Value Invested In Separate Accounts	21,549
Net amount at risk, gross	753
Net amount at risk, net of amounts reinsured	$ 236
Average attained age of policyholders	70 years 6 months
Weighted average years remaining until annuitization	1 year 7 months 6 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	$ 274
Account Value Invested In Separate Accounts	39,729
Net amount at risk, gross	5,793
Net amount at risk, net of amounts reinsured	$ 5,272
Average attained age of policyholders	69 years 1 month 6 days
Weighted average years remaining until annuitization	6 months 14 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%