NONINTEREST INCOME - Noninterest Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Income and Expenses [Abstract]
Revenue from contracts with customers	[1]	$ 285		$ 833
Revenue from other sources		131		342
Total noninterest income		$ 416	$ 381	$ 1,175	$ 1,130

[1] There is no revenue from contracts with customers included in Other non-segment operations.