INVESTMENTS - Rollforward of Net Unrealized Investment Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	$ 12,428	$ 19,492
Deferred income taxes	(200)	197
End of year	12,370	18,492
Accumulated Net Investment Gain (Loss) Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	(468)	679
Net investment gains (losses) arising during the period	1,583	(1,245)
Included in Net income (loss)	(3)	(88)
DAC	(655)	288
Deferred income taxes	(211)	197
Policyholders’ liabilities	77	108
End of year	323	(61)
Accumulated Net Investment Gain (Loss) Attributable to Parent | All other | Net Unrealized Gains (Losses) on Investments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	(577)	1,526
Net investment gains (losses) arising during the period	1,583	(1,245)
Included in Net income (loss)	(3)	(88)
End of year	1,003	193
Accumulated Net Investment Gain (Loss) Attributable to Parent | All other | DAC
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	39	(315)
DAC	(655)	288
End of year	(616)	(27)
Accumulated Net Investment Gain (Loss) Attributable to Parent | All other | Policyholders’ Liabilities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	(55)	(232)
Policyholders’ liabilities	77	108
End of year	22	(124)
Accumulated Net Investment Gain (Loss) Attributable to Parent | All other | Deferred Income Tax Asset (Liability)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	125	(300)
Deferred income taxes	(211)	197
End of year	(86)	(103)
Accumulated Net Investment Gain (Loss) Attributable to Parent | Fixed Maturities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	0	(4)
Net investment gains (losses) arising during the period	(10)	0
Included in Net income (loss)	10	(2)
DAC	0	(1)
Deferred income taxes	0	0
Policyholders’ liabilities	0	1
End of year	0	(6)
Accumulated Net Investment Gain (Loss) Attributable to Parent | Fixed Maturities | With OTTI loss | Net Unrealized Gains (Losses) on Investments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	0	1
Net investment gains (losses) arising during the period	(10)	0
End of year	0	(1)
Accumulated Net Investment Gain (Loss) Attributable to Parent | Fixed Maturities | With OTTI loss | DAC
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	0	1
DAC	0	(1)
End of year	0	0
Accumulated Net Investment Gain (Loss) Attributable to Parent | Fixed Maturities | With OTTI loss | Policyholders’ Liabilities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	0	(1)
Policyholders’ liabilities	0	1
End of year	0	0
Accumulated Net Investment Gain (Loss) Attributable to Parent | Fixed Maturities | With OTTI loss | Deferred Income Tax Asset (Liability)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning of year	0	(5)
Deferred income taxes	0	0
End of year	$ 0	$ (5)