SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Current assets	$ (1)	$ (5)	$ (47)
Other assets	(14)	15	43
Current liabilities	5	(82)	(38)
Long-term liabilities and equity	15	(17)	87
Other items, net	5	(89)	45
Interest Paid, Including Capitalized Interest, Operating and Investing Activities [Abstract]
Interest, net of amounts capitalized	191	235	239
Income Taxes Paid, Net [Abstract]
Income taxes	179	217	202
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Outstanding trade payables related to capital expenditures	$ 20	$ 22	$ 18

Future cash outflow to pay for purchases of fixed assets that have occurred.

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