Segment Information (Schedule Of Revenues By Product Line) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Sales and other operating revenue, including excise taxes	[1]		$ 74,104	$ 63,277
Sales and other operating revenues, excluding consumer excise taxes	[1],[2]	$ 95,750
Refined products
Segment Reporting Information [Line Items]
Sales and other operating revenue, including excise taxes			63,846	54,450
Sales and other operating revenues, excluding consumer excise taxes		83,888
Merchandise
Segment Reporting Information [Line Items]
Sales and other operating revenue, including excise taxes			5,174	5,297
Sales and other operating revenues, excluding consumer excise taxes		5,332
Crude oil and refinery feedstocks
Segment Reporting Information [Line Items]
Sales and other operating revenue, including excise taxes			3,403	2,038
Sales and other operating revenues, excluding consumer excise taxes		4,143
Midstream services, transportation and other
Segment Reporting Information [Line Items]
Sales and other operating revenue, including excise taxes			$ 1,681	$ 1,492
Sales and other operating revenues, excluding consumer excise taxes		$ 2,387

[1] The 2018 period reflects an election to present certain taxes on a net basis concurrent with our adoption of ASU 2014-09, Revenue - Revenue from Contracts with Customers (“ASC 606”). See Notes 2 and 3 for further information.

[2] The 2018 period reflects an election to present certain taxes on a net basis concurrent with our adoption of ASC 606.