INVESTMENTS - Recognition and Measurement of OTTI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
OTTI on Investments disclosures
Total OTTI losses recognized during the period	$ 0	$ 2	$ 0	$ 2
Less: portion of impairment loss recognized in AOCI (before taxes)	0	0	0	0
Net impairment losses recognized in earnings for debt securities that the Company does not intend to sell nor will likely be required to sell	0	2	0	2
Impairment losses recognized in earnings for debt securities that the Company intends to sell, would be more-likely-than-not required to sell or will be subject to an issuer call deemed probable of exercise	70	13	109	45
Total OTTI losses recognized in earnings	70	15	109	47
Securities available-for-sale (AFS)
OTTI on Investments disclosures
Total OTTI losses recognized during the period	0	2	0	2
Less: portion of impairment loss recognized in AOCI (before taxes)	0	0	0	0
Net impairment losses recognized in earnings for debt securities that the Company does not intend to sell nor will likely be required to sell	0	2	0	2
Impairment losses recognized in earnings for debt securities that the Company intends to sell, would be more-likely-than-not required to sell or will be subject to an issuer call deemed probable of exercise	70	12	109	43
Total OTTI losses recognized in earnings	70	14	109	45
Held-to-maturity securities
OTTI on Investments disclosures
Total OTTI losses recognized during the period	0	0	0	0
Less: portion of impairment loss recognized in AOCI (before taxes)	0	0	0	0
Net impairment losses recognized in earnings for debt securities that the Company does not intend to sell nor will likely be required to sell	0	0	0	0
Impairment losses recognized in earnings for debt securities that the Company intends to sell, would be more-likely-than-not required to sell or will be subject to an issuer call deemed probable of exercise	0	1	0	2
Total OTTI losses recognized in earnings	$ 0	$ 1	$ 0	$ 2