ACCOUNTS RECEIVABLE AND OTHER FINANCIAL ASSETS - Summary of the Activity of the Allowance for Expected Credit Losses on Prepayments to Customers (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Contract With Customer, Asset, Prepayments To Customers, Allowance for Credit Loss [Abstract]
Balance, beginning of year	$ 55	$ 6
Provision charged to expense	2	48
Write-offs and adjustments	(1)	0
Balance, end of period	$ 56	$ 54