Other Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest and Debt Expense
Incurred, debt	$ 432	$ 402	$ 389
Incurred, other	21	17	27
Total incurred	453	419	416
Capitalized	(15)	(81)	(106)
Expensed	438	338	310
Other Income
Interest income	31	18	27
Gain on consolidation of business	423	0	0
Other, net	67	56	91
Other Income	521	74	118
Research and Development Expenditures—expensed	60	60	65
Advertising Expenses	76	80	73
Foreign Currency Transaction Gain (Loss), by Segment [Line Items]
Foreign Currency Transaction (Gains) Losses—after-tax		(11)	38
Refining
Foreign Currency Transaction Gain (Loss), by Segment [Line Items]
Foreign Currency Transaction (Gains) Losses—after-tax	(1)	(10)	34
Marketing and Specialties
Foreign Currency Transaction Gain (Loss), by Segment [Line Items]
Foreign Currency Transaction (Gains) Losses—after-tax	1	1	4
Corporate and Other
Interest and Debt Expense
Expensed	$ 438	338	$ 310
Foreign Currency Transaction Gain (Loss), by Segment [Line Items]
Foreign Currency Transaction (Gains) Losses—after-tax		$ (2)