Retirement Benefit Plan (Schedule Of Defined Benefit Plans And Postretirement Benefit Plans) (Details) (USD $) In Millions	3 Months Ended						9 Months Ended				3 Months Ended			9 Months Ended
	Jun. 30, 2011 Toledo Refinery [Member]	Mar. 31, 2011 Toledo Refinery [Member]	Sep. 30, 2011 Defined Benefit Plans [Member]		Sep. 30, 2010 Defined Benefit Plans [Member]		Sep. 30, 2011 Defined Benefit Plans [Member]		Sep. 30, 2010 Defined Benefit Plans [Member]		Sep. 30, 2011 Postretirement Benefit Plans [Member]		Sep. 30, 2010 Postretirement Benefit Plans [Member]	Sep. 30, 2011 Postretirement Benefit Plans [Member]		Sep. 30, 2010 Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost (cost of benefits earned during the year)			$ 2		$ 4		$ 6		$ 21					$ 1		$ 2
Interest cost on benefit obligations			12		14		39		46		3		5	11		14
Expected return on plan assets			(17)		(17)		(51)		(52)
Amortization of actuarial losses			9		11		26		35				2	6		5
Amortization of prior service cost (benefit)											(5)		(6)	(15)		(15)
Defined benefit plan benefit cost before curtailments, settlements and special terminations			6		12		20		50		(2)		1	3		6
Settlement losses	22		14	[1]	18	[1]	38	[1]	45	[1]
Special terminations benefits and curtailment losses (gains)			1	[1]			8	[1]	3	[1]	(1)	[1]		(3)	[1]	(4)	[1]
Total expense			21		30		66		98		(3)		1			2
Special terminations benefits		6
Defined benefit plan, recognized net gain (loss) due to settlements and curtailments							$ 1		$ 3

[1] Includes special termination benefits and settlement losses of $6 and $22 million, respectively, recognized during the three and nine months ended September 30, 2011 attributable to the Toledo refinery (Note 3). Also includes net settlement and curtailment losses attributable to discontinued operations of $1 and $3 million, respectively, recognized during the nine months ended September 30, 2011 and 2010 (Note 2).