Income Taxes (Detail) $ in Billions	3 Months Ended
Mar. 31, 2018 USD ($)
Income Tax Narrative (Textual)
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit)	$ 1.9

Amount of reasonable estimate for income tax expense (benefit) from effect of Tax Cuts and Jobs Act of 2017 for which accounting for tax effect is incomplete.

No definition available.

Name:	vlo_TaxCutsAndJobsActOf2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefit
Namespace Prefix:	vlo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration