Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan, Change in Fair Value of Plan Assets Rollforward
Fair value of plan assets at beginning of year	$ 1,362,000,000
Fair value of plan assets at end of year	1,487,000,000
Employee Benefit Plans (Textual)
Number of employees covered by employee benefit plans	most
Thrift Plan [Member]
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	35,000,000	36,000,000	37,000,000
Employee Benefit Plans (Textual)
Number of employees covered by employee benefit plans	substantially all
Basic contributions by plan participants	6.00%		8.00%
Supplemental contribution by plan participants			22.00%
Employer's matching contribution on participant's total basic contributions	100.00%		75.00%
Valero Savings Plan [Member]
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	8,000,000	6,000,000	5,000,000
Employee Benefit Plans (Textual)
Basic contributions by plan participants	6.00%
Employer Contribution Amount	0.60
Participant's contribution matched by employer	1
Percentage of basic contributions by plan participants minimum	1.00%
Percentage of basic contributions by plan participants, maximum	0.3
Valero Savings Plan [Member] | Minimum [Member]
Employee Benefit Plans (Textual)
Discretionary employer matching contributions	3.50%
Valero Savings Plan [Member] | Maximum [Member]
Employee Benefit Plans (Textual)
Discretionary employer matching contributions	5.00%
Premcor Retirement Savings Plan [Member]
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	5,000,000	5,000,000	6,000,000
Employee Benefit Plans (Textual)
Contributions by employer for maximum contribution of participants	1
Contributions by employer for minimum contribution of participants	200.00%
Percentage of basic contributions by plan participants minimum	1.00%
Percentage of basic contributions by plan participants, maximum	0.5
Premcor Retirement Savings Plan [Member] | Participant Contributions - Tier 1 [Member]
Employee Benefit Plans (Textual)
Participant's pre-tax contribution	3.00%
Premcor Retirement Savings Plan [Member] | Participant Contributions - Tier 2 [Member]
Employee Benefit Plans (Textual)
Participant's pre-tax contribution	3.00%
Ultramar Ltd Savings Plan [Member]
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	10,000,000	9,000,000	8,000,000
Employee Benefit Plans (Textual)
Number of employees covered by employee benefit plans	all
Employer's matching contribution on participant's total basic contributions	50.00%
Employer contribution on basic salary	6.00%
Contributions by employer for maximum contribution of participants	0.12
Contributions by employer for minimum contribution of participants	9.00%
Benefit plan eligibility, service requirement description	three months
Benefit plan eligibility, service requirement	3 months
Ultramar Ltd Savings Plan [Member] | Eligibility - Temporary employees [Member]
Employee Benefit Plans (Textual)
Benefit plan eligibility, service requirement description	one year
Benefit plan eligibility, service requirement	1 year
Ultramar Ltd Savings Plan [Member] | Eligibility - Seasonal employees [Member]
Employee Benefit Plans (Textual)
Benefit plan eligibility, service requirement description	220 days of service during 36 consecutive months
Ultramar Ltd Savings Plan [Member] | Service Requirement - Days [Member]
Employee Benefit Plans (Textual)
Benefit plan eligibility, service requirement	220 days
Ultramar Ltd Savings Plan [Member] | Service Requirement - Consecutive Period [Member]
Employee Benefit Plans (Textual)
Benefit plan eligibility, service requirement	36 months
Aruba Thrift Plan [Member]
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	1,000,000	1,000,000	1,000,000
Employee Benefit Plans (Textual)
Number of employees covered by employee benefit plans	all
Employer's matching contribution on participant's total basic contributions	100.00%
Employer contribution on basic salary	8.00%
Contributions by employer for maximum contribution of participants	0.08
Benefit plan eligibility, service requirement description	one year
Benefit plan eligibility, service requirement	1 year
Nonqualified Defined Contribution Plans [Member]
Employer Contributions to Defined Contribution Plans
Contributions to defined contribution plans	0	0	0
Employee Benefit Plans (Textual)
Number of employee benefit plans	2
Mimimum Requirement [Member]
Employee Benefit Plans (Textual)
Future employer contributions to pension plans	2,000,000
Discretionary [Member]
Employee Benefit Plans (Textual)
Future employer contributions to pension plans	100,000,000
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation Rollforward
Benefit obligation at beginning of year	1,626,000,000	1,454,000,000
Service cost	104,000,000	88,000,000	104,000,000
Interest cost	85,000,000	83,000,000	79,000,000
Acquisitions	0	0
Participant contributions	0	0
Plan amendments	4,000,000	0
Special termination benefits	0	(4,000,000)
Medicare subsidy for prescription drugs	0	0
Benefits paid	(117,000,000)	(109,000,000)
Actuarial (gain) loss	179,000,000	106,000,000
Foreign currency exchange rate changes	0	0
Benefit obligation at end of year	1,881,000,000	1,626,000,000	1,454,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets Rollforward
Fair value of plan assets at beginning of year	1,362,000,000	1,251,000,000
Actual return on plan assets	(2,000,000)	149,000,000
Valero contributions	244,000,000	71,000,000
Participant contributions	0	0
Medicare subsidy for prescription drugs	0	0
Benefits paid	(117,000,000)	(109,000,000)
Fair value of plan assets at end of year	1,487,000,000	1,362,000,000	1,251,000,000
Reconciliation of funded status:
Funded status at end of year	(394,000,000)	(264,000,000)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation Rollforward
Benefit obligation at beginning of year	426,000,000	466,000,000
Service cost	11,000,000	10,000,000	12,000,000
Interest cost	22,000,000	26,000,000	25,000,000
Acquisitions	4,000,000	0
Participant contributions	12,000,000	12,000,000
Plan amendments	0	(31,000,000)
Special termination benefits	0	0
Medicare subsidy for prescription drugs	3,000,000	1,000,000
Benefits paid	(30,000,000)	(31,000,000)
Actuarial (gain) loss	(9,000,000)	(28,000,000)
Foreign currency exchange rate changes	(1,000,000)	1,000,000
Benefit obligation at end of year	438,000,000	426,000,000	466,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets Rollforward
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Valero contributions	15,000,000	18,000,000
Participant contributions	12,000,000	12,000,000
Medicare subsidy for prescription drugs	(3,000,000)	(1,000,000)
Benefits paid	(30,000,000)	(31,000,000)
Fair value of plan assets at end of year	0	0	0
Reconciliation of funded status:
Funded status at end of year	$ (438,000,000)	$ (426,000,000)