Fair Value Measurements (Reconciliation Of Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015		Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 215		$ 58		$ 270		$ 286
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	238		347		252		295
Total increase (decrease) in realized/unrealized losses included in cost of products sold	209	[1]	52	[2]	268	[3]	284	[4]
Purchases	6		2		12		6
Sales	(6)		(13)		(28)		(31)
Settlements	(114)		(238)		(249)		(450)
Transfers into Level 3	54		41		136		107
Transfers out of Level 3	(11)		(10)		(15)		(30)
Balance at end of period	376		181		376		181
Significant Unobservable Inputs (Level 3) [Member] | Inventory Related Payables [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	20		27		40		34
Total increase (decrease) in realized/unrealized losses included in cost of products sold	(6)	[1]	3	[2]	(11)	[3]	10	[4]
Purchases	6		2		12		6
Sales	(6)		(13)		(28)		(31)
Settlements	0		0		0		0
Transfers into Level 3	0		0		0		0
Transfers out of Level 3	(1)		0		0		0
Balance at end of period	13		19		13		19
Significant Unobservable Inputs (Level 3) [Member] | Commodity Derivative Contracts Losses [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	218		320		212		261
Total increase (decrease) in realized/unrealized losses included in cost of products sold	215	[1]	49	[2]	279	[3]	274	[4]
Purchases	0		0		0		0
Sales	0		0		0		0
Settlements	(114)		(238)		(249)		(450)
Transfers into Level 3	54		41		136		107
Transfers out of Level 3	(10)		(10)		(15)		(30)
Balance at end of period	$ 363		$ 162		$ 363		$ 162

[1] Includes increase in unrealized losses of $215 million relating to Level 3 liabilities still held at June 30, 2015.

[2] * Includes increase in unrealized losses of $58 million relating to Level 3 liabilities still held at June 30, 2014.

[3] * Includes increase in unrealized losses of $270 million relating to Level 3 liabilities still held at June 30, 2015.

[4] * Includes increase in unrealized losses of $286 million relating to Level 3 liabilities still held at June 30, 2014.