Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net sales	$ 4,056	$ 2,357
Income (loss) from operations	1,032	346
Depreciation and amortization	257	195
Other income, net	11	12
Provision for (benefit from) income taxes	233	72
Capital expenditures	263	141
Operating Segments [Member] | Olefins
Segment Reporting Information [Line Items]
Net sales	2,832	1,742
Income (loss) from operations	879	288
Depreciation and amortization	184	161
Other income, net	8	9
Provision for (benefit from) income taxes	202	62
Capital expenditures	221	127
Operating Segments [Member] | Vinyls
Segment Reporting Information [Line Items]
Net sales	1,224	615
Income (loss) from operations	185	71
Depreciation and amortization	71	32
Other income, net	2	2
Provision for (benefit from) income taxes	44	17
Capital expenditures	39	14
Operating Segments [Member] | Polyethylene [Member] | Olefins
Segment Reporting Information [Line Items]
Net sales	1,929	1,204
Operating Segments [Member] | Styrene, Feedstock And Other [Member] | Olefins
Segment Reporting Information [Line Items]
Net sales	903	538
Operating Segments [Member] | PVC, Caustic Soda And Other [Member] | Vinyls
Segment Reporting Information [Line Items]
Net sales	972	443
Operating Segments [Member] | Building Products [Member] | Vinyls
Segment Reporting Information [Line Items]
Net sales	252	172
Corporate and other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(32)	(13)
Depreciation and amortization	2	2
Other income, net	1	1
Provision for (benefit from) income taxes	(13)	(7)
Capital expenditures	3	0
Intersegment sales [Member]
Segment Reporting Information [Line Items]
Net sales	248	162
Intersegment sales [Member] | Olefins
Segment Reporting Information [Line Items]
Net sales	248	162
Intersegment sales [Member] | Vinyls
Segment Reporting Information [Line Items]
Net sales	$ 0	$ 0