Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Less dividends paid:
Weighted-average common shares outstanding (in millions) (shares)	442	461	497
Earnings per common share – assuming dilution:
Weighted-average common shares outstanding (in millions) (shares)	442	461	497
Weighted-average common shares outstanding – assuming dilution (in millions) (shares)	444	464	500
Common Class A [Member]
Earnings per common share from continuing operations:
Net income attributable to Valero stockholders	$ 4,065	$ 2,289	$ 3,990
Less dividends paid:
Common stock	1,238	1,108	845
Participating securities	4	3	3
Undistributed earnings	$ 2,823	$ 1,178	$ 3,142
Weighted-average common shares outstanding (in millions) (shares)	442	461	497
Earnings per common share:
Distributed earnings (in usd per share)	$ 2.80	$ 2.40	$ 1.70
Undistributed earnings (in usd per share)	6.37	2.54	6.30
Total earnings per common share (in usd per share)	$ 9.17	$ 4.94	$ 8.00
Earnings per common share – assuming dilution:
Net income attributable to Valero stockholders	$ 4,065	$ 2,289	$ 3,990
Weighted-average common shares outstanding (in millions) (shares)	442	461	497
Weighted-average common equivalent shares outstanding (in millions) (shares)	2	3	3
Weighted-average common shares outstanding – assuming dilution (in millions) (shares)	444	464	500
Earnings per common share – assuming dilution (in usd per share)	$ 9.16	$ 4.94	$ 7.99
Participating Securities [Member]
Less dividends paid:
Weighted-average common shares outstanding (in millions) (shares)	2	1	2
Earnings per common share:
Distributed earnings (in usd per share)	$ 2.80	$ 2.40	$ 1.70
Undistributed earnings (in usd per share)	6.37	2.54	6.30
Total earnings per common share (in usd per share)	$ 9.17	$ 4.94	$ 8.00
Earnings per common share – assuming dilution:
Weighted-average common shares outstanding (in millions) (shares)	2	1	2