Revenues, Key product revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of revenue [Abstract]
Sales and other operating revenues	$ 6,776	$ 8,722	$ 19,816	$ 26,548
Olefins & co-products [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	568	709	1,695	2,202
Polyethylene [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	1,423	1,509	4,159	4,713
Polypropylene [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	1,103	1,251	3,173	3,883
Propylene oxide and derivatives [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	421	481	1,217	1,498
Oxyfuels and related products [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	573	837	1,669	2,298
Intermediate chemicals [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	486	655	1,434	2,000
Compounding and solutions [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	834	991	2,295	3,193
Advanced polymers [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	169	194	501	588
Refined products [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	1,003	1,952	3,193	5,706
Other [Member]
Disaggregation of revenue [Abstract]
Sales and other operating revenues	$ 196	$ 143	$ 480	$ 467