Assets and Liabilities with Recurring Fair Value Measurements Fair Value Hierarchy (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	$ 786	$ 1,134
Margin deposits	[2]	120	89
Commodity futures contracts		1,036	1,736
Commodity forward contracts	[3]	238	274
Interest Rate Derivative Assets, Fair Value		8	1
Total assets		2,188	3,234
Margin deposits held by us posted by our counterparties	[2],[4]	30	35
Commodity futures contracts		1,004	1,604
Commodity forward contracts	[3]	342	513
Interest Rate Derivative Liabilities At Fair Value		81	90
Liabilities, Fair Value Disclosure		1,457	2,242
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	786	1,134
Margin deposits		120	89
Commodity futures contracts		1,036	1,736
Commodity forward contracts	[3]	0	0
Interest Rate Derivative Assets, Fair Value		0	0
Total assets		1,942	2,959
Margin deposits held by us posted by our counterparties		30	35
Commodity futures contracts		1,004	1,604
Commodity forward contracts	[3]	0	0
Interest Rate Derivative Liabilities At Fair Value		0	0
Liabilities, Fair Value Disclosure		1,034	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]	178	220
Interest Rate Derivative Assets, Fair Value		8	1
Total assets		186	221
Margin deposits held by us posted by our counterparties		0	0
Commodity futures contracts		0	0
Commodity forward contracts	[3]	310	413
Interest Rate Derivative Liabilities At Fair Value		81	90
Liabilities, Fair Value Disclosure		391	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]	60	54
Interest Rate Derivative Assets, Fair Value		0	0
Total assets		60	54
Margin deposits held by us posted by our counterparties		0	0
Commodity futures contracts		0	0
Commodity forward contracts	[3]	32	100
Interest Rate Derivative Liabilities At Fair Value		0	0
Liabilities, Fair Value Disclosure		$ 32	$ 100

[1] As of September 30, 2016 and December 31, 2015, we had cash equivalents of $561 million and $906 million included in cash and cash equivalents and $225 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.