Acquisitions (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended
Jul. 31, 2013 Eagle Ford [Member] acres	Sep. 30, 2012 Eagle Ford Paloma [Member] acres	Jul. 31, 2013 Eagle Ford Paloma [Member]
Business Acquisition [Line Items]
Fair Value Inputs, Discount Rate	10.00%	10.00%
Gas and oil acreages undeveloped and developed net	4,800	20,000
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination [Abstract]
Payments to Acquire Businesses, Gross	$ 74	$ 768
Business Combination, Consideration Transferred, Other	23
Business Combination, Consideration Transferred	97
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents			8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables			22
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory			1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets			31
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment			822
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets			853
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable			78
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities,Asset Retirement Obligations			7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			85
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			$ 768

Amount of asset retirement obligations, assumed at the acquisition date.

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- Definition

Acreage is considered to be both developed and undeveloped. Developed acres are acres spaced or assigned to productive wells. Undeveloped acreage are those lease acres on which wells have not been drilled or completed to a point that would permit the producing.

+ References

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

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- Definition

Amount of tangible or intangible assets, including a business or subsidiary of the acquirer transferred by the entity to the former owners of the acquiree. Excludes cash.

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- Definition

Amount of assets acquired at the acquisition date.

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Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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- Definition

Amount of assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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- Definition

Amount of liabilities incurred for goods and services received that are used in an entity's business and related party payables, assumed at the acquisition date.

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- Definition

The amount of inventory recognized as of the acquisition date.

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Amount of liabilities assumed at the acquisition date.

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- Definition

Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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The amount of property, plant, and equipment recognized as of the acquisition date.

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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-Glossary Investing Activities

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