Summary of Accounting Policies (Variable Interest Entities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Total assets	$ 11,975	$ 10,909
Property, plant and equipment (net of accumulated depreciation - 2021: $3,484; 2020: $3,279)	$ 4,193	3,939
Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Ownership percentage	50.00%
Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Maximum exposure to loss	$ 235	267
Fairway Methanol LLC [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Total assets	628	666
Property, plant and equipment (net of accumulated depreciation - 2021: $3,484; 2020: $3,279)	$ 560	$ 592