Restructuring, Impairment, and Plant Closing and Transition Costs - Restructuring, Impairment and Plant Closing and Transition Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring and Related Activities [Abstract]
Cash charges	$ 1	$ 5	$ 11	$ 19
Impairment of assets	3	0	3	0
Early settlement of contractual obligation	0	0	0	(14)
Accelerated depreciation	9	7	11	19
Total Restructuring, Impairment and Plant Closing and Transition Costs	$ 13	$ 12	$ 25	$ 24