Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders from continuing operations	$ 1,351	$ 651	$ 2,315	$ 1,480
Less dividends paid:
Weighted-average common shares outstanding (in shares)	505	529	509	530
Earnings per common share from continuing operations:
Total earnings per common share from continuing operations (in usd per share)	$ 2.67	$ 1.23	$ 4.53	$ 2.78
Earnings per common share from continuing operations – assuming dilution:
Net income attributable to Valero stockholders from continuing operations	$ 1,351	$ 651	$ 2,315	$ 1,480
Weighted-average common shares outstanding (in shares)	505	529	509	530
Common equivalent shares:
Weighted-average common shares outstanding – assuming dilution (in shares)	508	534	512	535
Earnings per common share from continuing operations – assuming dilution (in usd per share)	$ 2.66	$ 1.22	$ 4.52	$ 2.77
Common Stock [Member]
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders from continuing operations	$ 1,351	$ 651	$ 2,315	$ 1,480
Less dividends paid:
Common stock	203	133	408	265
Participating securities			1	1
Undistributed earnings	$ 1,148	$ 518	$ 1,906	$ 1,214
Weighted-average common shares outstanding (in shares)	505	529	509	530
Earnings per common share from continuing operations:
Distributed earnings (in usd per share)	$ 0.40	$ 0.25	$ 0.80	$ 0.50
Undistributed earnings (in usd per share)	2.27	0.98	3.73	2.28
Total earnings per common share from continuing operations (in usd per share)	$ 2.67	$ 1.23	$ 4.53	$ 2.78
Earnings per common share from continuing operations – assuming dilution:
Net income attributable to Valero stockholders from continuing operations	$ 1,351	$ 651	$ 2,315	$ 1,480
Weighted-average common shares outstanding (in shares)	505	529	509	530
Common equivalent shares:
Stock options (in shares)	2	3	2	3
Performance awards and nonvested restricted stock (in shares)	1	2	1	2
Weighted-average common shares outstanding – assuming dilution (in shares)	508	534	512	535
Earnings per common share from continuing operations – assuming dilution (in usd per share)	$ 2.66	$ 1.22	$ 4.52	$ 2.77
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	$ 0.25	$ 0.80	$ 0.50
Undistributed earnings (in usd per share)	2.27	0.98	3.73	2.28
Total earnings per common share from continuing operations (in usd per share)	$ 2.67	$ 1.23	$ 4.53	$ 2.78
Earnings per common share from continuing operations – assuming dilution:
Weighted-average common shares outstanding (in shares)	2	2	2	2