Assets and Liabilities with Recurring Fair Value Measurements Fair Value Hierarchy (Details) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	$ 383	$ 1,134
Margin deposits	[2]	134	89
Commodity futures contracts		1,316	1,736
Commodity forward contracts	[3]	275	274
Interest Rate Derivative Assets, Fair Value		9	1
Total assets		2,117	3,234
Margin deposits held by us posted by our counterparties	[2],[4]	9	35
Commodity futures contracts		1,248	1,604
Commodity forward contracts	[3]	528	513
Interest Rate Derivative Liabilities At Fair Value		96	90
Liabilities, Fair Value Disclosure		1,881	2,242
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	383	1,134
Margin deposits		134	89
Commodity futures contracts		1,316	1,736
Commodity forward contracts	[3]	0	0
Interest Rate Derivative Assets, Fair Value		0	0
Total assets		1,833	2,959
Margin deposits held by us posted by our counterparties		9	35
Commodity futures contracts		1,248	1,604
Commodity forward contracts	[3]	0	0
Interest Rate Derivative Liabilities At Fair Value		0	0
Liabilities, Fair Value Disclosure		1,257	1,639
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	0	0
Margin deposits		0	0
Commodity futures contracts		0	0
Commodity forward contracts	[3]	232	220
Interest Rate Derivative Assets, Fair Value		9	1
Total assets		241	221
Margin deposits held by us posted by our counterparties		0	0
Commodity futures contracts		0	0
Commodity forward contracts	[3]	422	413
Interest Rate Derivative Liabilities At Fair Value		96	90
Liabilities, Fair Value Disclosure		518	503
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	0	0
Margin deposits		0	0
Commodity futures contracts		0	0
Commodity forward contracts	[3]	43	54
Interest Rate Derivative Assets, Fair Value		0	0
Total assets		43	54
Margin deposits held by us posted by our counterparties		0	0
Commodity futures contracts		0	0
Commodity forward contracts	[3]	106	100
Interest Rate Derivative Liabilities At Fair Value		0	0
Liabilities, Fair Value Disclosure		$ 106	$ 100

[1] As of June 30, 2016 and December 31, 2015, we had cash equivalents of $215 million and $906 million included in cash and cash equivalents and $168 million and $228 million included in restricted cash, respectively.

[2] Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Condensed Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values. See Note 6 for further discussion of our derivative instruments subject to master netting arrangements.

[3] Includes OTC swaps and options.

[4] Included in other current liabilities on our Consolidated Condensed Balance Sheets.