Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Less dividends paid:
Weighted-average common shares outstanding (in shares)	431	448
Earnings per common share – assuming dilution:
Weighted-average common shares outstanding (in shares)	431	448
Weighted-average common shares outstanding – assuming dilution (in shares)	432	451
Common Class A [Member]
Earnings per common share:
Net income attributable to Valero stockholders	$ 469	$ 305
Less dividends paid:
Common stock	344	314
Participating securities	1	1
Undistributed earnings (excess distributions over earnings)	$ 124	$ (10)
Weighted-average common shares outstanding (in shares)	431	448
Earnings per common share:
Distributed earnings (in usd per share)	$ 0.80	$ 0.70
Undistributed earnings (excess distributions over earnings) (in usd per share)	0.29	(0.02)
Total earnings per common share (in usd per share)	$ 1.09	$ 0.68
Earnings per common share – assuming dilution:
Net income attributable to Valero stockholders	$ 469	$ 305
Weighted-average common shares outstanding (in shares)	431	448
Common equivalent shares (in shares)	1	3
Weighted-average common shares outstanding – assuming dilution (in shares)	432	451
Earnings per common share – assuming dilution (in usd per share)	$ 1.09	$ 0.68
Participating Securities [Member]
Less dividends paid:
Weighted-average common shares outstanding (in shares)	1	2
Earnings per common share:
Distributed earnings (in usd per share)	$ 0.80	$ 0.70
Undistributed earnings (excess distributions over earnings) (in usd per share)	0.29	0.00
Total earnings per common share (in usd per share)	$ 1.09	$ 0.70
Earnings per common share – assuming dilution:
Weighted-average common shares outstanding (in shares)	1	2