Fair Value Measurements (Reconciliation Of Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 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)	$ 55		$ 228
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	252		295
Total increase (decrease) in unrealized losses included in cost of products sold	59	[1]	232	[2]
Purchases	6		4
Sales	(22)		(18)
Settlements	(135)		(212)
Transfers into Level 3	83		66
Transfers out of Level 3	(5)		(20)
Balance at end of period	238		347
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	40		34
Total increase (decrease) in unrealized losses included in cost of products sold	(5)	[1]	7	[2]
Purchases	6		4
Sales	(22)		(18)
Settlements	0		0
Transfers into Level 3	1		0
Transfers out of Level 3	0		0
Balance at end of period	20		27
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	212		261
Total increase (decrease) in unrealized losses included in cost of products sold	64	[1]	225	[2]
Purchases	0		0
Sales	0		0
Settlements	(135)		(212)
Transfers into Level 3	82		66
Transfers out of Level 3	(5)		(20)
Balance at end of period	$ 218		$ 320

[1] Includes increase in unrealized losses of $55 million relating to Level 3 liabilities still held at March 31, 2015.

[2] * Includes increase in unrealized losses of $228 million relating to Level 3 liabilities still held at March 31, 2014.