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	6 Months Ended	12 Months Ended
	Dec. 31, 2012	Jun. 30, 2012
Inventory Related Payables [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 38	$ 45
Total increase (decrease) in unrealized gains included in cost of products sold	1	1
Purchases	8	(8)
Sales	(17)
Transfers into Level 3	3
Balance at end of period	33	38
Commodity Derivative Contracts Losses [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	179	44
Total increase (decrease) in unrealized gains included in cost of products sold	139	555
Settlements	(235)	(384)
Transfers into Level 3	101	72
Transfers out of Level 3	(46)	(108)
Balance at end of period	138	179
Total Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	217	89
Total increase (decrease) in unrealized gains included in cost of products sold	140	556
Purchases	8	(8)
Sales	(17)
Settlements	(235)	(384)
Transfers into Level 3	104	72
Transfers out of Level 3	(46)	(108)
Balance at end of period	$ 171	$ 217