ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Recorded Investment in Loan and Leases (Details) (Loans and Leases, USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated	$ 1,405	$ 1,439
Formula-based evaluation	89,344	84,420
Total	90,749	85,859
Total commercial
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated	191	239
Formula-based evaluation	41,279	39,156
Total	41,470	39,395
Total retail
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated	1,214	1,200
Formula-based evaluation	48,065	45,264
Total	$ 49,279	$ 46,464