This item represents the aggregate carrying amount of all cost-method investments as reported on or included in the balance sheet. The original cost of the investments may differ from the aggregate carrying amount disclosed due to various adjustments such as: (i) dividends received in excess of earnings after the date of investment that are considered a return of investment and therefore recorded as reductions to cost of the investment, or (ii) a series of operating losses of an investee or other factors which may indicate that a decrease in value of the investment has occurred which is other than temporary and accordingly such decrease in value has been recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References+ Details

Investments Schedule of Investments Table (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Jul. 31, 2011
Schedule of Equity Method Investments [Line Items]
Investments	$ 728	$ 1,531
FTS International, Inc.
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	30.00%
Equity Method Investments	298	235
Chaparral Energy, Inc.
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	20.00%
Equity Method Investments	141	143
Sundrop Fuels, Inc.
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Equity Method Investments	111	34
Clean Energy Fuels Corp.
Schedule of Equity Method Investments [Line Items]
Cost method percentage approximate owned	0.00%
Fair Value Method Investment Ownership Percentage	1.00%
Cost Method Investments	100	50
Fair Value Method Investments	12	12
Twin Eagle Resources Management, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	30.00%
Equity Method Investments	34	20
Maalt Specialized Bulk, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	49.00%
Equity Method Investments	13	12
Gastar Exploration Ltd.
Schedule of Equity Method Investments [Line Items]
Fair Value Method Investment Ownership Percentage	10.00%
Fair Value Method Investments	8	22
Chesapeake Midstream Partners, L.P.
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	0	987
Other Investment Companies
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	$ 11	$ 16