Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings per common share:
Net income attributable to Valero stockholders	$ 141	$ 469
Less income allocated to participating securities	1	1
Net income available to common stockholders	$ 140	$ 468
Weighted-average common shares outstanding (in shares)	416	431
Earnings per common share (in dollars per share)	$ 0.34	$ 1.09
Earnings per common share – assuming dilution:
Net income attributable to Valero stockholders	$ 141	$ 469
Weighted-average common shares outstanding (in shares)	416	431
Effect of dilutive securities (in shares)	2	1
Weighted-average common shares outstanding – assuming dilution (in shares)	418	432
Earnings per common share – assuming dilution (in dollars per share)	$ 0.34	$ 1.09