Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in plan assets(a):
Fair value of plan assets at beginning of year	$ 1,978
Fair value of plan assets at end of year	1,947	$ 1,978
Defined Benefit Plan, Amounts Recognized in Balance Sheet
Accrued expenses	(40)	(48)
Other long-term liabilities	(719)	(792)
Employee Benefit Plans (Textual)
Contributions to defined contribution plans	65	61	$ 62
Pension Plans [Member]
Changes in benefit obligation:
Benefit obligation at beginning of year	2,450	1,914
Service cost	109	120	137
Interest cost	98	91	86
Participant contributions	0	0
Plan amendments	22	2
Benefits paid	(169)	(109)
Actuarial (gain) loss	(138)	440
Other	(7)	(8)
Benefit obligation at end of year	2,365	2,450	1,914
Changes in plan assets(a):
Fair value of plan assets at beginning of year	1,978	1,909
Actual return on plan assets	19	139
Valero contributions	126	46
Participant contributions	0	0
Benefits paid	(169)	(109)
Other	(7)	(7)
Fair value of plan assets at end of year	1,947	1,978	1,909
Reconciliation of funded status (a):
Funded status as of end of year	(418)	(472)
Accumulated benefit obligation	2,240	2,354
Defined Benefit Plan, Amounts Recognized in Balance Sheet
Deferred charges and other assets, net	5	7
Accrued expenses	(20)	(28)
Other long-term liabilities	(403)	(451)
Amounts recognized in balance sheet for defined benefit plans	(418)	(472)
Employee Benefit Plans (Textual)
Initial effect of defined benefit plan amendment			(328)
Remeasurement due to plan amendments	0	0	328
Other Postretirement Benefit Plans [Member]
Changes in benefit obligation:
Benefit obligation at beginning of year	361	324
Service cost	8	7	12
Interest cost	14	15	18
Participant contributions	8	7
Plan amendments	0	0
Benefits paid	(27)	(30)
Actuarial (gain) loss	(26)	37
Other	(2)	1
Benefit obligation at end of year	336	361	324
Changes in plan assets(a):
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Valero contributions	18	20
Participant contributions	8	7
Benefits paid	(27)	(30)
Other	1	3
Fair value of plan assets at end of year	0	0	0
Reconciliation of funded status (a):
Funded status as of end of year	(336)	(361)
Defined Benefit Plan, Amounts Recognized in Balance Sheet
Deferred charges and other assets, net	0	0
Accrued expenses	(20)	(20)
Other long-term liabilities	(316)	(341)
Amounts recognized in balance sheet for defined benefit plans	(336)	(361)
Employee Benefit Plans (Textual)
Initial effect of defined benefit plan amendment			(43)
Remeasurement due to plan amendments	$ 0	$ 0	$ 43