Sales and Other Operating Revenues (Disaggregated) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues	$ 29,125	$ 27,218	$ 27,847	$ 23,103	$ 29,098	$ 29,788	$ 28,980	$ 23,595	$ 107,293	$ 111,461
Sales and other operating revenues											$ 102,354
United States
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									83,512	86,401
Sales and other operating revenues											75,684
United Kingdom
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									9,863	11,054
Sales and other operating revenues											10,626
Germany
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									4,053	4,352
Sales and other operating revenues											6,692
Other foreign countries
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									9,865	9,654
Sales and other operating revenues											9,352
Refined petroleum products
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									87,902	87,967
Sales and other operating revenues											85,405
Crude oil resales
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									14,125	16,419
Sales and other operating revenues											11,808
NGL
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									4,814	6,161
Sales and other operating revenues											4,670
Services and other
Revenue from External Customer [Line Items]
Sales and Other Operating Revenues									$ 452	$ 914
Sales and other operating revenues											$ 471