LOANS AND LEASES - Components of Investments in Leases (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total future minimum lease rentals	$ 3,195
Total leases	46,214	$ 43,226
Finance Leases Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total future minimum lease rentals	3,195	3,324
Estimated residual value of leased equipment (non-guaranteed)	1,157	1,059
Initial direct costs	22	22
Unearned income on minimum lease rentals and estimated residual value of leased equipment	(395)	(419)
Total leases	$ 3,979	$ 3,986