FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value Of Assets And Liabilities (Details) $ in Millions	Dec. 31, 2019 USD ($)
Assets:
Cash equivalents	$ 188
Total Asset	233
Other Current Assets [Member] | Customer Supply Agreements [Member]
Assets:
Derivative Asset	45
Fair Value, Inputs, Level 1 [Member]
Assets:
Cash equivalents	0
Total Asset	0
Fair Value, Inputs, Level 1 [Member] | Other Current Assets [Member] | Customer Supply Agreements [Member]
Assets:
Derivative Asset	0
Fair Value, Inputs, Level 2 [Member]
Assets:
Cash equivalents	188
Total Asset	188
Fair Value, Inputs, Level 2 [Member] | Other Current Assets [Member] | Customer Supply Agreements [Member]
Assets:
Derivative Asset	0
Fair Value, Inputs, Level 3 [Member]
Assets:
Cash equivalents	0
Total Asset	45
Fair Value, Inputs, Level 3 [Member] | Other Current Assets [Member] | Customer Supply Agreements [Member]
Assets:
Derivative Asset	$ 45