Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

Fair value of assets and liabilities measured on recurring basis

The tables below present information (in millions) about our assets and liabilities recognized at their fair values in our balance sheets categorized according to the fair value hierarchy of the inputs utilized by us to determine the fair values as of September 30, 2014 and December 31, 2013.

We have elected to offset the fair value amounts recognized for multiple similar derivative contracts executed with the same counterparty, including any related cash collateral assets or obligations as shown below; however, fair value amounts by hierarchy level are presented on a gross basis in the tables below. We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.

	September 30, 2014
							Total Gross Fair Value		Effect of Counter- party Netting			Effect of Cash Collateral Netting			Net Carrying Value on Balance Sheet		Cash Collateral Paid or Received Not Offset
	Fair Value Hierarchy
	Level 1		Level 2		Level 3
Assets:
Commodity derivative contracts	$	1,334	$	42	$	—	$	1,376	$	(1,222	)	$	(84	)	$	70	$	—
Foreign currency contracts	8		—		—		8		n/a			n/a			8		n/a
Investments of certain benefit plans	101		—		11		112		n/a			n/a			112		n/a
Total	$	1,443	$	42	$	11	$	1,496	$	(1,222	)	$	(84	)	$	190
Liabilities:
Commodity derivative contracts	$	1,185	$	51	$	—	$	1,236	$	(1,222	)	$	(14	)	$	—	$	(49	)
Biofuels blending obligation	—		8		—		8		n/a			n/a			8		n/a
Physical purchase contracts	—		17		—		17		n/a			n/a			17		n/a
Total	$	1,185	$	76	$	—	$	1,261	$	(1,222	)	$	(14	)	$	25

	December 31, 2013
							Total Gross Fair Value		Effect of Counter- party Netting			Effect of Cash Collateral Netting			Net Carrying Value on Balance Sheet		Cash Collateral Paid or Received Not Offset
	Fair Value Hierarchy
	Level 1		Level 2		Level 3
Assets:
Commodity derivative contracts	$	499	$	38	$	—	$	537	$	(505	)	$	(7	)	$	25	$	—
Investments of certain benefit plans	98		—		11		109		n/a			n/a			109		n/a
Total	$	597	$	38	$	11	$	646	$	(505	)	$	(7	)	$	134
Liabilities:
Commodity derivative contracts	$	492	$	24	$	—	$	516	$	(505	)	$	(6	)	$	5	$	(76	)
Biofuels blending obligation	—		11		—		11		n/a			n/a			11		n/a
Physical purchase contracts	—		5		—		5		n/a			n/a			5		n/a
Foreign currency contracts	8		—		—		8		n/a			n/a			8		n/a
Total	$	500	$	40	$	—	$	540	$	(505	)	$	(6	)	$	29

Carrying amounts and estimated fair value of financial instruments

Financial instruments that we recognize in our balance sheets at their carrying amounts are shown in the table below (in millions):

	September 30, 2014				December 31, 2013
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Financial assets:
Cash and temporary cash investments	$	4,191	$	4,191	$	4,292	$	4,292
Financial liabilities:
Debt (excluding capital leases)	6,347		7,685		6,525		7,659