Operating Segments and Geographic Data - Segement Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	$ 2,691	$ 5,715	$ (48)
Operating Segments | Upstream
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	1,942	5,498	(1,289)
Operating Segments | Upstream | United States
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	(1,550)	811	(3,538)
Operating Segments | Upstream | International
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	3,492	4,687	2,249
Operating Segments | Downstream
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	562	862	231
Operating Segments | Downstream | United States
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	392	534	(419)
Operating Segments | Downstream | International
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	170	328	650
Segment Reconciling Items
Segment Reporting Information [Line Items]
Total Income Tax Expense (Benefit)	$ 187	$ (645)	$ 1,010