INSURANCE LIABILITIES - Variable Annuity Contracts with GMDB and GMIB Features (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
GMDB
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 14,517
Account Value Invested In Separate Accounts	90,343	$ 83,154
Net Amount At Risk By Product And Guarantee, Account Value	104,860
Net amount at risk, gross	20,700
Net amount at risk, net of amounts reinsured	$ 20,084
Average attained age of policyholders (in years)	55 years 3 months 19 days
Percentage of policyholders over age 70	19.00%
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	$ 14,178
Account Value Invested In Separate Accounts	45,599
Net Amount At Risk By Product And Guarantee, Account Value	59,777
Net amount at risk, gross	143
Net amount at risk, net of amounts reinsured	$ 143
Average attained age of policyholders (in years)	51 years 4 months 24 days
Percentage of policyholders over age 70	10.20%
GMDB | Ratchet
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 98
Account Value Invested In Separate Accounts	9,001
Net Amount At Risk By Product And Guarantee, Account Value	9,099
Net amount at risk, gross	143
Net amount at risk, net of amounts reinsured	$ 138
Average attained age of policyholders (in years)	67 years 1 month 6 days
Percentage of policyholders over age 70	43.50%
GMDB | Roll-Up
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 60
Account Value Invested In Separate Accounts	3,134
Net Amount At Risk By Product And Guarantee, Account Value	3,194
Net amount at risk, gross	2,025
Net amount at risk, net of amounts reinsured	$ 1,414
Average attained age of policyholders (in years)	73 years 9 months 18 days
Percentage of policyholders over age 70	66.10%
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	$ 181
Account Value Invested In Separate Accounts	32,609
Net Amount At Risk By Product And Guarantee, Account Value	32,790
Net amount at risk, gross	18,389
Net amount at risk, net of amounts reinsured	$ 18,389
Average attained age of policyholders (in years)	69 years 2 months 12 days
Percentage of policyholders over age 70	50.70%
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	$ 264
Account Value Invested In Separate Accounts	57,668	$ 52,835
Net Amount At Risk By Product And Guarantee, Account Value	57,932
Net amount at risk, gross	9,185
Net amount at risk, net of amounts reinsured	$ 7,796
Average attained age of policyholders (in years)	69 years
Weighted average years remaining until annuitization	6 months
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 | Return of Premium
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	$ 0
Account Value Invested In Separate Accounts	0
Net Amount At Risk By Product And Guarantee, Account Value	0
Net amount at risk, gross	0
Net amount at risk, net of amounts reinsured	0
GMIB | Ratchet
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	0
Account Value Invested In Separate Accounts	0
Net Amount At Risk By Product And Guarantee, Account Value	0
Net amount at risk, gross	0
Net amount at risk, net of amounts reinsured	0
GMIB | Roll-Up
Net Amount at Risk by Product and Guarantee [Line Items]
Account Value Invested In General Account	19
Account Value Invested In Separate Accounts	21,923
Net Amount At Risk By Product And Guarantee, Account Value	21,942
Net amount at risk, gross	898
Net amount at risk, net of amounts reinsured	$ 281
Average attained age of policyholders (in years)	69 years
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	$ 245
Account Value Invested In Separate Accounts	35,745
Net Amount At Risk By Product And Guarantee, Account Value	35,990
Net amount at risk, gross	8,287
Net amount at risk, net of amounts reinsured	$ 7,515
Average attained age of policyholders (in years)	69 years
Weighted average years remaining until annuitization	4 months 24 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%