COMMITMENTS AND CONTINGENCIES - Schedule of Outstanding Off-balance sheet Arrangements (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Other Commitments [Line Items]
Commitment amount	$ 60,794	$ 58,746
Undrawn commitments to extend credit
Other Commitments [Line Items]
Commitment amount	58,622	56,524
Financial standby letters of credit
Other Commitments [Line Items]
Commitment amount	1,946	2,010
Performance letters of credit
Other Commitments [Line Items]
Commitment amount	37	42
Commercial letters of credit
Other Commitments [Line Items]
Commitment amount	70	87
Marketing rights
Other Commitments [Line Items]
Commitment amount	46	47
Risk participation agreements
Other Commitments [Line Items]
Commitment amount	64	26
Residential mortgage loans sold with recourse
Other Commitments [Line Items]
Commitment amount	$ 9	$ 10