VARIABLE INTEREST ENTITIES - Schedule of Affordable Housing Tax Credit Investments (Details) - LIHTC Investments - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Variable Interest Entity
Tax credits included in income tax expense	$ 28	$ 20	$ 79	$ 63
Amortization expense included in income tax expense	31	22	86	67
Other tax benefits included in income tax expense	$ 7	$ 7	$ 19	$ 22