Ventures and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Cash and cash equivalents		$ 463	$ 439	$ 576	$ 638
Trade receivables - third party and affiliates		850	1,017
Property, plant and equipment (net of accumulated depreciation - 2019: $174; 2018: $130)		3,713	3,719
Accumulated depreciation		2,957	2,803
Intangible assets, net		312	310
Accumulated amortization		612	595	$ 591
Other assets		338	290
Total assets		9,476	9,313
Trade payables		780	819
Current installments of long-term debt		28	367
Current liabilities		1,754	1,779
Deferred income taxes		257	255
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents		57	24
Trade receivables - third party and affiliates		6	6
Property, plant and equipment (net of accumulated depreciation - 2019: $174; 2018: $130)		622	659
Intangible assets, net		22	23
Other assets		9	5
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Property, plant and equipment (net of accumulated depreciation - 2019: $174; 2018: $130)		31	42
Trade payables		30	27
Current installments of long-term debt		16	14
Long-term debt		41	58
Total liabilities		87	99
Maximum exposure to loss		113	134
Fairway Methanol LLC [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents		57	24
Trade receivables - third party and affiliates		12	11
Property, plant and equipment (net of accumulated depreciation - 2019: $174; 2018: $130)		622	659
Accumulated depreciation		174	130
Intangible assets, net		22	23
Accumulated amortization		4	3
Other assets		9	5
Total assets	[1]	722	722
Trade payables		24	16
Current liabilities	[2]	5	4
Long-term debt		4	5
Deferred income taxes		4	3
Total liabilities		$ 37	$ 28

[1] Joint venture assets can only be used to settle the obligations of Fairway.

[2] Primarily represents amounts owed by Fairway to the Company for reimbursement of expenditures.