NONINTEREST INCOME - Noninterest Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Income and Expenses [Abstract]
Revenue from contracts with customers	$ 1,172	$ 1,119
Revenue from other sources	705	477
Total noninterest income	$ 1,877	$ 1,596	$ 1,534