Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings (loss) per common share
Net income (loss) attributable to Valero stockholders	$ (464)	$ 609	$ (1,062)	$ 1,362
Less: Income allocated to participating securities	1	1	4	3
Net income (loss) available to common stockholders	$ (465)	$ 608	$ (1,066)	$ 1,359
Weighted-average common shares outstanding (in shares)	407	412	407	415
Earnings (loss) per common share (in dollars per share)	$ (1.14)	$ 1.48	$ (2.62)	$ 3.28
Earnings (loss) per common share – assuming dilution
Net income (loss) attributable to Valero stockholders	$ (464)	$ 609	$ (1,062)	$ 1,362
Less: Income allocated to participating securities	1	1	4	3
Net income (loss) available to common stockholders	$ (465)	$ 608	$ (1,066)	$ 1,359
Weighted-average common shares outstanding (in shares)	407	412	407	415
Effect of dilutive securities (in shares)	0	1	0	1
Weighted-average common shares outstanding – assuming dilution (in shares)	407	413	407	416
Earnings (loss) per common share – assuming dilution (in dollars per share)	$ (1.14)	$ 1.48	$ (2.62)	$ 3.28