Variable Interest Entities, Consolidated (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Assets
Cash and temporary cash investments	$ 4,658	$ 5,850	$ 4,463	$ 4,816
Property, plant, and equipment, net	27,731	27,480
Liabilities
Current liabilities	10,752	11,071
Debt and capital lease obligations, less current portion	8,086	8,750
Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and temporary cash investments	130	179
Other current assets	253	72
Property, plant, and equipment, net	2,071	2,029
Liabilities
Current liabilities	72	95
Debt and capital lease obligations, less current portion	1,030	948
Valero Energy Partners LP [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and temporary cash investments	71	42
Other current assets	1	2
Property, plant, and equipment, net	1,416	1,416
Liabilities
Current liabilities	26	27
Debt and capital lease obligations, less current portion	989	905
Diamond Green Diesel Holdings LLC [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and temporary cash investments	41	123
Other current assets	243	66
Property, plant, and equipment, net	475	435
Liabilities
Current liabilities	34	33
Debt and capital lease obligations, less current portion	0	0
VPM Terminals [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and temporary cash investments	1	1
Other current assets	9	4
Property, plant, and equipment, net	57	51
Liabilities
Current liabilities	3	26
Debt and capital lease obligations, less current portion	0	0
Other Variable Interest Entities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and temporary cash investments	17	13
Other current assets	0	0
Property, plant, and equipment, net	123	127
Liabilities
Current liabilities	9	9
Debt and capital lease obligations, less current portion	$ 41	$ 43