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.

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-Name Accounting Principles Board Opinion (APB)

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-Name Accounting Standards Codification

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-Publisher FASB

-Name FASB Staff Position (FSP)

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-Name Emerging Issues Task Force (EITF)

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+ 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

Schedule of Investments (Detail) (USD $) In Millions, unless otherwise specified			9 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Chesapeake Midstream Partners, L.P.	Dec. 31, 2011 Chesapeake Midstream Partners, L.P.	Sep. 30, 2012 Frac Tech Holdings, L.L.C.	Sep. 30, 2012 FTS International, LLC	Dec. 31, 2011 FTS International, LLC	Sep. 30, 2012 Chaparral Energy, Inc.	Dec. 31, 2011 Chaparral Energy, Inc.	Sep. 30, 2012 Sundrop Fuels, Inc.	Dec. 31, 2011 Sundrop Fuels, Inc.	Jul. 31, 2011 Sundrop Fuels, Inc.	Sep. 30, 2012 Clean Energy Fuels Corp.	Dec. 31, 2011 Clean Energy Fuels Corp.	Sep. 30, 2012 Twin Eagle Resources Management, LLC	Dec. 31, 2011 Twin Eagle Resources Management, LLC	Sep. 30, 2012 Gastar Exploration Ltd.	Dec. 31, 2011 Gastar Exploration Ltd.	Sep. 30, 2012 Other Investment Companies	Dec. 31, 2011 Other Investment Companies	Sep. 30, 2012 Utica East Ohio Midstream L.L.C	Mar. 31, 2012 Utica East Ohio Midstream L.L.C	Dec. 31, 2011 Utica East Ohio Midstream L.L.C	Sep. 30, 2012 Ranch Westex Jv Llc [Member]	Dec. 31, 2011 Ranch Westex Jv Llc [Member]	Sep. 30, 2012 Glass Mountain Pipeline Limited Liability Company	Apr. 30, 2012 Glass Mountain Pipeline Limited Liability Company	Dec. 31, 2011 Glass Mountain Pipeline Limited Liability Company
Schedule of Equity Method Investments [Line Items]
Equity method accretion adjustments			$ 4		$ 34
Equity method percentage approximate owned			0.00%			30.00%		20.00%				50.00%	0.00%		30.00%						59.00%	59.00%		33.00%		25.00%	50.00%
Cost method percentage approximate owned										50.00%
Fair Value Method Investment Ownership Percentage													1.00%				10.00%
Equity Method Investments	123	0	0	987		201	235	144	143	112	34				30	20					75		0	32	0	16		0
Cost Method Investments													100	50					36	28
Fair Value Method Investments													13	12			11	22
Investments	$ 647	$ 1,531