SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Future Minimum Lease Payments (Details) $ in Millions	Sep. 30, 2019 USD ($)
Operating Leases
2019	$ 48
2020	124
2021	50
2022	41
2023	24
Thereafter	40
Total future minimum lease payments	327
Less: imputed interest	(26)
Total lease liabilities	301
Current portion	(149)
Non-current portion	152
Finance Leases
2019	9
2020	13
2021	3
2022	3
2023	3
Thereafter	40
Total future minimum lease payments	71
Less: imputed interest	(14)
Total lease liabilities	57
Current portion	(19)
Non-current portion	$ 38