INVESTMENTS - Credit Loss Impairments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 1,556	$ 373	$ 2,917	$ 3,801
Gross gains on sales	9	7	17	134
Gross losses on sales	(6)	(14)	(21)	(55)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of year	12,370	18,492	12,428	19,492
End of year	13,932	16,946	13,932	16,946
Accumulated Other-than-Temporary Impairment Attributable to Parent [Member] | Fixed Maturities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of year	(18)	(10)	(46)	(10)
Previously recognized impairments on securities that matured, paid, prepaid or sold	0	1	28	1
Recognized impairments on securities impaired to fair value this period	0	0	0	0
Impairments recognized this period on securities not previously impaired	0	0	0	0
Additional impairments this period on securities previously impaired	0	0	0	0
Increases due to passage of time on previously recorded credit losses	0	0	0	0
Accretion of previously recognized impairments due to increases in expected cash flows	0	0	0	0
End of year	$ (18)	$ (9)	$ (18)	$ (9)