Segment Information (Schedule Of Revenues By Product Line) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 63,339	$ 72,051	$ 97,817
Refined products
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	54,511	63,744	90,702
Merchandise
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	5,297	5,188	3,817
Crude oil and refinery feedstocks
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	2,038	2,718	2,917
Service, transportation and other
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 1,493	$ 401	$ 381