LEASES - Balance Sheet Information Related to Leases (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease right-of-use assets	$ 221	$ 237	$ 0
Finance lease, right-of-use asset	16
Total lease assets	237
Operating lease, liability, current	67
Finance lease, liability, current	5
Non-current operating lease liabilities	155		$ 0
Non-current finance leases	17
Total lease liabilities	$ 244