Contingent Liabilities and Commitments (Details) - USD ($) $ in Millions		1 Months Ended
	May 20, 2016	Jan. 31, 2020	Dec. 31, 2020
Loss Contingencies [Line Items]
Accrued environmental loss liabilities			$ 33
Capital Addition Purchase Commitments [Member]
Loss Contingencies [Line Items]
Commitments for construction and acquisition of property, plant, and equipment			262
Former Alaska Refinery [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		$ 86
Energy Transfer Merger [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 1,480
Gas Pipeline [Member]
Loss Contingencies [Line Items]
Accrued environmental loss liabilities			4
Natural Gas Underground Storage Facilities [Member]
Loss Contingencies [Line Items]
Accrued environmental loss liabilities			8
Former Operations [Member]
Loss Contingencies [Line Items]
Accrued environmental loss liabilities			$ 21