Variable Interest Entities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Assets
Cash and temporary cash investments	$ 5,207	$ 4,816	$ 4,925	$ 4,114
Property, plant, and equipment, net	27,054	26,472
Liabilities
Current liabilities	7,683	8,328
Debt and capital lease obligations, less current portion	8,366	7,886
Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and temporary cash investments	255	253
Other current assets	56	90
Property, plant, and equipment, net	1,446	1,353
Liabilities
Current liabilities	37	39
Debt and capital lease obligations, less current portion	570	571
Valero Energy Partners LP [Member]
Assets
Cash and temporary cash investments	88	71
Other current assets	1	3
Property, plant, and equipment, net	945	865
Liabilities
Current liabilities	14	15
Debt and capital lease obligations, less current portion	525	525
Diamond Green Diesel Holdings LLC [Member]
Assets
Cash and temporary cash investments	155	167
Other current assets	55	87
Property, plant, and equipment, net	371	355
Liabilities
Current liabilities	17	17
Debt and capital lease obligations, less current portion	0	0
Other Variable Interest Entities [Member]
Assets
Cash and temporary cash investments	12	15
Other current assets	0	0
Property, plant, and equipment, net	130	133
Liabilities
Current liabilities	6	7
Debt and capital lease obligations, less current portion	$ 45	$ 46