Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings per common share
Net income attributable to Valero stockholders	$ 1,060	$ 609	$ 612	$ 141	$ 952	$ 856	$ 845	$ 469	$ 2,422	$ 3,122	$ 4,065
Less: Income allocated to participating securities									7	9	14
Net income available to common shareholders									$ 2,415	$ 3,113	$ 4,051
Weighted-average common shares outstanding (shares)									413	426	442
Earnings per common share (in usd per share)	$ 2.58	$ 1.48	$ 1.47	$ 0.34	$ 2.26	$ 2.01	$ 1.96	$ 1.09	$ 5.84	$ 7.30	$ 9.17
Earnings per common share – assuming dilution
Net income attributable to Valero stockholders	$ 1,060	$ 609	$ 612	$ 141	$ 952	$ 856	$ 845	$ 469	$ 2,422	$ 3,122	$ 4,065
Weighted-average common shares outstanding (shares)									413	426	442
Effect of dilutive securities (shares)									1	2	2
Weighted-average common shares outstanding – assuming dilution (shares)									414	428	444
Earnings per common share – assuming dilution (in usd per share)	$ 2.58	$ 1.48	$ 1.47	$ 0.34	$ 2.24	$ 2.01	$ 1.96	$ 1.09	$ 5.84	$ 7.29	$ 9.16