Fair Value Measurements (Reconciliation Of Liabilities Measured At Fair Value On A Recurring Basis) (Details) (Significant Unobservable Inputs (Level 3) [Member], Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unrealized losses on derivative liabilities	$ 127			$ 237
Inventory Related Payables [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	63		38	33		196
Total increase (decrease) in unrealized losses included in cost of products sold	0	[1]	0	(191)	[2]	0
Purchases	4		2	190		2
Sales	(17)		0	(23)		(4)
Settlements	0		0	0		0
Transfers into Level 3	0		0	0		2
Transfers out of Level 3	(41)		0	0		(156)
Balance at end of period	9		40	9		40
Commodity Derivative Contracts Losses [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	233		179	138		192
Total increase (decrease) in unrealized losses included in cost of products sold	127	[1]	86	382	[2]	335
Purchases	0		0	0		(1)
Sales	0		0	0		0
Settlements	(186)		(105)	(397)		(350)
Transfers into Level 3	30		73	104		126
Transfers out of Level 3	(18)		(16)	(41)		(85)
Balance at end of period	186		217	186		217
Total Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	296		217	171		388
Total increase (decrease) in unrealized losses included in cost of products sold	127	[1]	86	191	[2]	335
Purchases	4		2	190		1
Sales	(17)		0	(23)		(4)
Settlements	(186)		(105)	(397)		(350)
Transfers into Level 3	30		73	104		128
Transfers out of Level 3	(59)		(16)	(41)		(241)
Balance at end of period	$ 195		$ 257	$ 195		$ 257

[1] Includes losses of $127 million that are attributable to the change in unrealized losses relating to Level 3 liabilities still held at September 30, 2013.

[2] Includes losses of $237 million that are attributable to the change in unrealized losses relating to Level 3 liabilities still held at September 30, 2013.