Fair Value Measurements, Level 3 Reconciliation (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investments of Certain Benefit Plans [Member]
Reconciliation of Beginning and Ending Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs
Balance as of beginning of year	$ 11	$ 11	$ 10
Purchases	0	0	1
Transfers in and/or out of Level 3	0	0	0
Balance as of end of year	11	11	11
Investments of Certain Benefit Plans [Member] | Operating Expense [Member] | Refining [Member]
Reconciliation of Beginning and Ending Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs
Total losses included in refining operating expense	0	0	0
Investments of Certain Benefit Plans [Member] | Other Income [Member]
Reconciliation of Beginning and Ending Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs
The amount of total losses included in income attributable to the change in unrealized losses relating to assets still held at end of year	0	0	0
Other Investments [Member]
Reconciliation of Beginning and Ending Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs
Balance as of beginning of year	0	0	0
Purchases	0	0	21
Transfers in and/or out of Level 3	0	0	0
Balance as of end of year	0	0	0
Other Investments [Member] | Operating Expense [Member] | Refining [Member]
Reconciliation of Beginning and Ending Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs
Total losses included in refining operating expense	0	0	(21)
Other Investments [Member] | Other Income [Member]
Reconciliation of Beginning and Ending Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs
The amount of total losses included in income attributable to the change in unrealized losses relating to assets still held at end of year	$ 0	$ 0	$ (21)