Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Defined Benefit Plan, Change in Fair Value of Plan Assets Rollforward
Fair value of plan assets at beginning of year	$ 1,487
Fair value of plan assets at end of year	1,729		1,487
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	61		59		57
Minimum Requirement [Member]
Employee Benefit Plans (Textual)
Future employer contributions to pension and other postretirement plans	30
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation Rollforward
Benefit obligation at beginning of year	1,881		1,626
Service cost	140		104		88
Interest cost	93		85		83
Participant contributions	0		0
Plan amendments	9		4
Curtailment gain	(16)		0
Benefits paid	(90)		(117)
Actuarial (gain) loss	289		179
Other	1		0
Benefit obligation at end of year	2,307		1,881		1,626
Defined Benefit Plan, Change in Fair Value of Plan Assets Rollforward
Fair value of plan assets at beginning of year	1,487	[1]	1,362	[1]
Actual return on plan assets	167		(2)
Valero contributions	164		244
Participant contributions	0		0
Benefits paid	(90)		(117)
Other	1		0
Fair value of plan assets at end of year	1,729	[1]	1,487	[1]	1,362	[1]
Reconciliation of funded status:
Funded status at end of year	(578)		(394)
Accumulated benefit obligation	1,857		1,550
Pension Plans [Member] | Discretionary [Member]
Employee Benefit Plans (Textual)
Future employer contributions to pension and other postretirement plans	115
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation Rollforward
Benefit obligation at beginning of year	438		426
Service cost	12		11		10
Interest cost	21		22		26
Participant contributions	14		12
Plan amendments	0		0
Curtailment gain	0		0
Benefits paid	(35)		(30)
Actuarial (gain) loss	(17)		(9)
Other	3		6
Benefit obligation at end of year	436		438		426
Defined Benefit Plan, Change in Fair Value of Plan Assets Rollforward
Fair value of plan assets at beginning of year	0	[1]	0	[1]
Actual return on plan assets	0		0
Valero contributions	19		15
Participant contributions	14		12
Benefits paid	(35)		(30)
Other	2		3
Fair value of plan assets at end of year	0	[1]	0	[1]	0	[1]
Reconciliation of funded status:
Funded status at end of year	(436)		(438)
Other Postretirement Benefit Plans [Member] | Discretionary [Member]
Employee Benefit Plans (Textual)
Future employer contributions to pension and other postretirement plans	$ 21

[1] (a)Plan assets include only the assets associated with pension plans subject to legal minimum funding standards. Plan assets associated with U.S. nonqualified pension plans are not included here because they are not protected from our creditors and therefore cannot be reflected as a reduction from our obligations under the pension plans. As a result, the reconciliation of funded status does not reflect the effect of plan assets that exist for all of our defined benefit plans. See Note 20 for the assets associated with certain U.S. nonqualified pension plans.