Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Loss per common share
Net loss attributable to Valero stockholders	$ (704)	$ (1,851)
Less: Income allocated to participating securities	1	1
Net loss available to common stockholders	$ (705)	$ (1,852)
Weighted-average common shares outstanding (in shares)	407	408
Loss per common share (in dollars per share)	$ (1.73)	$ (4.54)
Loss per common share – assuming dilution
Net loss attributable to Valero stockholders	$ (704)	$ (1,851)
Less: Income allocated to participating securities	1	0
Net loss available to common stockholders	$ (705)	$ (1,851)
Weighted-average common shares outstanding – assuming dilution (in shares)	407	408
Loss per common share – assuming dilution (in dollars per share)	$ (1.73)	$ (4.54)