Segment Disclosures and Related Information - Sales (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 7,518	$ 5,121
Alaska [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	1,007	778
Lower 48 Before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	3,230	2,145
Intersegment Eliminations before Lower 48 [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3)	(7)
Lower 48 [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	3,227	2,138
Canada before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	870	425
Intersegment Eliminations before Canada [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	(86)	(35)
Canada [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	784	390
Europe and North Africa before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	1,443	923
Asia Pacific and Midle East Before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	1,022	837
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 35	$ 55