Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders from continuing operations	$ 3,694	$ 2,714	$ 3,117
Less dividends paid:
Weighted-average common shares outstanding (in millions)	526	542	550
Earnings per common share from continuing operations:
Total earnings per common share from continuing operations	$ 7.00	$ 4.98	$ 5.64
Earnings per common share from continuing operations – assuming dilution:
Net income attributable to Valero stockholders from continuing operations	3,694	2,714	3,117
Weighted-average common shares outstanding (in millions)	526	542	550
Common equivalent shares:
Weighted-average common shares outstanding – assuming dilution (in millions)	530	548	556
Earnings per common share from continuing operations – assuming dilution (in usd per share)	$ 6.97	$ 4.96	$ 5.61
Common Stock [Member]
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders from continuing operations	3,694	2,714	3,117
Less dividends paid:
Common stock	552	460	358
Nonvested restricted stock	2	2	2
Undistributed earnings	3,140	2,252	2,757
Weighted-average common shares outstanding (in millions)	526	542	550
Earnings per common share from continuing operations:
Distributed earnings (in usd per share)	$ 1.05	$ 0.85	$ 0.65
Undistributed earnings (in usd per share)	$ 5.95	$ 4.13	$ 4.99
Total earnings per common share from continuing operations	$ 7.00	$ 4.98	$ 5.64
Earnings per common share from continuing operations – assuming dilution:
Net income attributable to Valero stockholders from continuing operations	$ 3,694	$ 2,714	$ 3,117
Weighted-average common shares outstanding (in millions)	526	542	550
Common equivalent shares:
Stock options (in shares)	2	4	4
Performance awards and nonvested restricted stock (in shares)	2	2	2
Weighted-average common shares outstanding – assuming dilution (in millions)	530	548	556
Earnings per common share from continuing operations – assuming dilution (in usd per share)	$ 6.97	$ 4.96	$ 5.61
Restricted Stock [Member]
Less dividends paid:
Weighted-average common shares outstanding (in millions)	2	3	3
Earnings per common share from continuing operations:
Distributed earnings (in usd per share)	$ 1.05	$ 0.85	$ 0.65
Undistributed earnings (in usd per share)	$ 5.95	$ 4.13	$ 4.99
Total earnings per common share from continuing operations	$ 7.00	$ 4.98	$ 5.64
Earnings per common share from continuing operations – assuming dilution:
Weighted-average common shares outstanding (in millions)	2	3	3