Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders from continuing operations	$ 1,377	$ 1,059	$ 3,692	$ 2,539
Less dividends paid:
Weighted-average common shares outstanding (in shares)	491	526	503	529
Earnings per common share from continuing operations:
Total earnings per common share from continuing operations (in usd per share)	$ 2.79	$ 2.01	$ 7.31	$ 4.78
Earnings per common share from continuing operations – assuming dilution:
Net income attributable to Valero stockholders from continuing operations	$ 1,377	$ 1,059	$ 3,692	$ 2,539
Weighted-average common shares outstanding (in shares)	491	526	503	529
Common equivalent shares:
Weighted-average common shares outstanding – assuming dilution (in shares)	494	530	506	533
Earnings per common share from continuing operations – assuming dilution (in usd per share)	$ 2.79	$ 2.00	$ 7.30	$ 4.76
Common Class A [Member]
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders from continuing operations	$ 1,377	$ 1,059	$ 3,692	$ 2,539
Less dividends paid:
Common stock	198	145	606	410
Participating securities	1	0	2	1
Undistributed earnings	$ 1,178	$ 914	$ 3,084	$ 2,128
Weighted-average common shares outstanding (in shares)	491	526	503	529
Earnings per common share from continuing operations:
Distributed earnings (in usd per share)	$ 0.40	$ 0.28	$ 1.20	$ 0.77
Undistributed earnings (in usd per share)	2.39	1.73	6.11	4.01
Total earnings per common share from continuing operations (in usd per share)	$ 2.79	$ 2.01	$ 7.31	$ 4.78
Earnings per common share from continuing operations – assuming dilution:
Net income attributable to Valero stockholders from continuing operations	$ 1,377	$ 1,059	$ 3,692	$ 2,539
Weighted-average common shares outstanding (in shares)	491	526	503	529
Common equivalent shares:
Stock options (in shares)	1	2	2	3
Performance awards and nonvested restricted stock (in shares)	2	2	1	1
Weighted-average common shares outstanding – assuming dilution (in shares)	494	530	506	533
Earnings per common share from continuing operations – assuming dilution (in usd per share)	$ 2.79	$ 2.00	$ 7.30	$ 4.76
Participating Securities [Member]
Less dividends paid:
Weighted-average common shares outstanding (in shares)	2	2	2	2
Earnings per common share from continuing operations:
Distributed earnings (in usd per share)	$ 0.40	$ 0.28	$ 1.20	$ 0.77
Undistributed earnings (in usd per share)	2.39	1.73	6.11	4.01
Total earnings per common share from continuing operations (in usd per share)	$ 2.79	$ 2.01	$ 7.31	$ 4.78
Earnings per common share from continuing operations – assuming dilution:
Weighted-average common shares outstanding (in shares)	2	2	2	2