Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended			3 Months Ended												12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	[1]	Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020	[2]	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Quarterly Financial Data
Revenues					$ 16,604		$ 15,809	[1],[2]	$ 10,397	[2]	$ 22,102		$ 27,879	$ 27,249	$ 28,933	$ 24,263	$ 64,912	[3]	$ 108,324	[3]	$ 117,033	[3]
Gross profit (loss)	[4]				(230)		(398)	[1],[2]	1,973	[2]	(2,085)		2,003	1,119	1,123	533
Operating income (loss)					(470)		(621)	[1],[2]	1,789	[2]	(2,277)		1,739	881	908	308	(1,579)		3,836		4,572
Net income (loss)					(309)		(379)	[1],[2]	1,335	[2]	(1,754)		1,330	639	648	167	(1,107)		2,784		3,353
Net income (loss) attributable to Valero Energy Corporation stockholders					$ (359)		$ (464)	[1],[2]	$ 1,253	[2]	$ (1,851)		$ 1,060	$ 609	$ 612	$ 141	$ (1,421)		$ 2,422		$ 3,122
Earnings (loss) per common share (in usd per share)					$ (0.88)		$ (1.14)	[1],[2]	$ 3.07	[2]	$ (4.54)		$ 2.58	$ 1.48	$ 1.47	$ 0.34	$ (3.50)		$ 5.84		$ 7.30
Earnings (loss) per common share – assuming dilution (in usd per share)					$ (0.88)		$ (1.14)	[1],[2]	$ 3.07	[2]	$ (4.54)		$ 2.58	$ 1.48	$ 1.47	$ 0.34	$ (3.50)		$ 5.84		$ 7.29
Quarterly Financial Data (Textual):
Lower of cost or market (LCM) inventory valuation adjustment				$ 2,500			$ (300)		$ (2,200)								$ (19)		$ 0		$ 0
Effect of LIFO Inventory Liquidation on Income		$ 102	$ (326)														$ (224)

[1] We recorded a charge of $326 million in September 2020 due to the expected liquidation of LIFO inventory layers as described in Note 5. We recognized a benefit of $102 million in December 2020 to adjust the $326 million estimate to the $224 million actual charge for the year ended December 31, 2020.

[2] The market value of our inventories accounted for under the LIFO method fell below their historical cost on an aggregate basis as of March 31, 2020. As a result, we recorded an LCM inventory valuation adjustment of $2.5 billion in March 2020 as described in Note 5. The market value of our LIFO inventories improved due to the subsequent recovery in market prices, which resulted in a reversal of $2.2 billion in the quarter ended June 30, 2020 and the remaining amount in the quarter ended September 30, 2020.

[3] Includes excise taxes on sales by certain of our international operations of $4,797 million, $5,595 million, and $5,626 million for the years ended December 31, 2020, 2019, and 2018.

[4] Gross profit is calculated as revenues less total cost of sales.