Commitments and Contingencies Level 4 (Details) - Environmental Liabilities - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Accrued Environmental Loss Contingencies, Current		$ 14	$ 18
Liability	[1]	47	51
Discontinued Operations
Liability		$ 2	2
Geismar, LA [Member]
Discount rate assumed to record at present value		3.00%
Undiscounted Liability Expected to be Paid		20 years
Geismar, LA Site Contingency, Accrual, Undiscounted Amount		$ 16
Accrual for Environmental Loss Contingencies, Undiscounted, Due Ratably over the Next Five Years		5
Formerly-Owned - Remediation [Member]
Accrued Environmental Loss Contingencies, Current		10
Liability		18	21
Estimated Litigation Liability, Noncurrent		8
Superfund and Offsite Landfills - allocated share: Equal to or Greater than 1% [Member]
Liability		6	6
Superfund and Offsite Landfills - Less than 1% [Member]
Liability		3	3
Geismar, LA [Member]
Liability		12	12
Formerly-Owned - Monitoring Only [Member]
Liability		0	1
Currently-Owned [Member]
Liability		8	$ 8
Minimum [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		34
Minimum [Member] | Formerly-Owned - Remediation [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		14
Minimum [Member] | Superfund and Offsite Landfills - allocated share: Equal to or Greater than 1% [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		5
Minimum [Member] | Superfund and Offsite Landfills - Less than 1% [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		2
Minimum [Member] | Geismar, LA [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		9
Minimum [Member] | Formerly-Owned - Monitoring Only [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		0
Minimum [Member] | Currently-Owned [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		4
Maximum [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		93
Maximum [Member] | Formerly-Owned - Remediation [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		36
Maximum [Member] | Superfund and Offsite Landfills - allocated share: Equal to or Greater than 1% [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		14
Maximum [Member] | Superfund and Offsite Landfills - Less than 1% [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		6
Maximum [Member] | Geismar, LA [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		22
Maximum [Member] | Formerly-Owned - Monitoring Only [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		1
Maximum [Member] | Currently-Owned [Member]
Site Contingency, Loss Exposure Not Accrued, Best Estimate		$ 14

[1] The table includes approximately $2 of environmental remediation liabilities related to the Held for Sale Business at both December 31, 2020 and 2019. These associated liabilities have been included in “Long-term liabilities associated with assets held for sale” within the Consolidated Balance Sheets.