LOANS - Corporate Lease Financing (Details) - Corporate $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Lessor, Lease, Description [Line Items]
Direct financing and leveraged leases, financing receivables	$ 1,500	$ 1,500
Direct financing and leveraged leases, interest income	21	$ 42
Direct financing and leveraged leases, weighted average remaining lease term		4 years
Direct financing and leveraged leases, residual value of leased assets	900	$ 900
Amount covered by residual value guarantees	$ 300	$ 300