INVESTMENTS - Recognition and Measurement of Impairment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
OTTI on Investments disclosures
Total impairment 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 more-likely-than-not be required to sell or will be subject to an issuer call deemed probable of exercise	30	13	101	18
Total impairment losses recognized in earnings	30	13	101	18
Debt securities available-for-sale (AFS)
OTTI on Investments disclosures
Total impairment 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 more-likely-than-not be required to sell or will be subject to an issuer call deemed probable of exercise	30	13	101	18
Total impairment losses recognized in earnings	30	13	101	18
Debt securities held-to-maturity (HTM)
OTTI on Investments disclosures
Total impairment losses recognized during the period		0		0
Less: portion of impairment loss recognized in AOCI (before taxes)		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
Impairment losses recognized in earnings for debt securities that the Company intends to sell, would more-likely-than-not be required to sell or will be subject to an issuer call deemed probable of exercise		0		0
Total impairment losses recognized in earnings		0		0
Other assets
OTTI on Investments disclosures
Total impairment 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 more-likely-than-not be required to sell or will be subject to an issuer call deemed probable of exercise	0	0	0	0
Total impairment losses recognized in earnings	$ 0	$ 0	$ 0	$ 0