Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 14,719	$ 13,835
Operating Segments [Member] | Olefins [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,050	1,923
Operating Segments [Member] | Vinyls
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	11,039	10,680
Corporate and other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 1,630	$ 1,232