COMMITMENTS AND CONTINGENCIES - Schedule of Outstanding Off-balance sheet Arrangements (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Other Commitments [Line Items]
Commitment amount	$ 57,721	$ 58,435
Undrawn commitments to extend credit
Other Commitments [Line Items]
Commitment amount	55,224	55,899
Financial standby letters of credit
Other Commitments [Line Items]
Commitment amount	2,292	2,315
Performance letters of credit
Other Commitments [Line Items]
Commitment amount	60	65
Commercial letters of credit
Other Commitments [Line Items]
Commitment amount	58	75
Marketing rights
Other Commitments [Line Items]
Commitment amount	51	51
Risk participation agreements
Other Commitments [Line Items]
Commitment amount	26	19
Residential mortgage loans sold with recourse
Other Commitments [Line Items]
Commitment amount	$ 10	$ 11