Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings per common share:
Net income attributable to Valero stockholders	$ 952	$ 856	$ 845	$ 469	$ 2,371		$ 841	$ 548	$ 305	$ 3,122	$ 4,065	$ 2,289
Less income allocated to participating securities										9	14	7
Net income available to common shareholders										$ 3,113	$ 4,051	$ 2,282
Weighted-average common shares outstanding (shares)										426	442	461
Earnings per common share (in usd per share)										$ 7.30	$ 9.17	$ 4.94
Earnings per common share – assuming dilution:
Net income attributable to Valero stockholders	$ 952	$ 856	$ 845	$ 469	$ 2,371		$ 841	$ 548	$ 305	$ 3,122	$ 4,065	$ 2,289
Weighted-average common shares outstanding (shares)										426	442	461
Effect of dilutive securities (shares)										2	2	3
Weighted-average common shares outstanding – assuming dilution (shares)										428	444	464
Earnings per common share – assuming dilution (in usd per share)										$ 7.29	$ 9.16	$ 4.94

[1] During the quarter ended December 31, 2017, we recognized an income tax benefit of $1.9 billion related to Tax Reform as described in Note 15.