SUPPLEMENTAL CASH FLOW INFORMATION (Cash Transactions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Interest Paid, Net of Amounts Capitalized	$ 76	$ 80	$ 67
Income Tax Refunds	$ (14)	$ (14)	$ 0