LEASES MATURITIES OF LEASE LIABILITIES (Details) $ in Millions	Jun. 30, 2019 USD ($)
Aircraft [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 128
Lessee, Operating Lease, Liability, Payments, Due Year Two	233
Lessee, Operating Lease, Liability, Payments, Due Year Three	194
Lessee, Operating Lease, Liability, Payments, Due Year Four	169
Lessee, Operating Lease, Liability, Payments, Due Year Five	115
Lessee, Operating Lease, Liability, Payments, Due after Year Five	324
Lessee, Operating Lease, Liability, Payments, Due	1,163
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(151)
Operating Lease, Liability	1,012
CPA Aircraft [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	40
Lessee, Operating Lease, Liability, Payments, Due Year Two	79
Lessee, Operating Lease, Liability, Payments, Due Year Three	79
Lessee, Operating Lease, Liability, Payments, Due Year Four	79
Lessee, Operating Lease, Liability, Payments, Due Year Five	79
Lessee, Operating Lease, Liability, Payments, Due after Year Five	408
Lessee, Operating Lease, Liability, Payments, Due	764
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(142)
Operating Lease, Liability	622
Airport Facilities [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	1
Lessee, Operating Lease, Liability, Payments, Due Year Two	3
Lessee, Operating Lease, Liability, Payments, Due Year Three	3
Lessee, Operating Lease, Liability, Payments, Due Year Four	2
Lessee, Operating Lease, Liability, Payments, Due Year Five	2
Lessee, Operating Lease, Liability, Payments, Due after Year Five	12
Lessee, Operating Lease, Liability, Payments, Due	23
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(4)
Operating Lease, Liability	19
Corporate real estate [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	5
Lessee, Operating Lease, Liability, Payments, Due Year Two	8
Lessee, Operating Lease, Liability, Payments, Due Year Three	6
Lessee, Operating Lease, Liability, Payments, Due Year Four	3
Lessee, Operating Lease, Liability, Payments, Due Year Five	2
Lessee, Operating Lease, Liability, Payments, Due after Year Five	74
Lessee, Operating Lease, Liability, Payments, Due	98
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(54)
Operating Lease, Liability	$ 44