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Variable Interest Entities, Consolidated (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 3,551	$ 5,850	$ 5,176	$ 4,816
Property, plant, and equipment, net	28,428	27,480
Liabilities
Current liabilities, including current portion of debt and capital lease obligations	12,482	11,071
Debt and capital lease obligations, less current portion	8,877	8,750
Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and cash equivalents	227	179
Other current assets	163	72
Property, plant, and equipment, net	2,237	2,029
Liabilities
Current liabilities, including current portion of debt and capital lease obligations	174	95
Debt and capital lease obligations, less current portion	1,028	948
Valero Energy Partners LP [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and cash equivalents	128	42
Other current assets	1	2
Property, plant, and equipment, net	1,414	1,416
Liabilities
Current liabilities, including current portion of debt and capital lease obligations	34	27
Debt and capital lease obligations, less current portion	990	905
Diamond Green Diesel Holdings LLC [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and cash equivalents	78	123
Other current assets	94	66
Property, plant, and equipment, net	567	435
Liabilities
Current liabilities, including current portion of debt and capital lease obligations	40	33
Debt and capital lease obligations, less current portion	0	0
Central Mexico Terminals [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Assets
Cash and cash equivalents	1	1
Other current assets	17	4
Property, plant, and equipment, net	138	51
Liabilities
Current liabilities, including current portion of debt and capital lease obligations	95	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 cash equivalents	20	13
Other current assets	51	0
Property, plant, and equipment, net	118	127
Liabilities
Current liabilities, including current portion of debt and capital lease obligations	5	9
Debt and capital lease obligations, less current portion	$ 38	$ 43