Valuation of Investments and Financial Instrument Assets Liabilities By Pricing Levels (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund investments	$ 1us-gaap_MoneyMarketFundsAtCarryingValue	$ 2us-gaap_MoneyMarketFundsAtCarryingValue
Deferred Compensation Plan Assets	9us-gaap_DeferredCompensationPlanAssets	8us-gaap_DeferredCompensationPlanAssets
Total	618us-gaap_AssetsFairValueDisclosure	5us-gaap_AssetsFairValueDisclosure
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	10	8
Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		39
Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and gas derivative contracts	994
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund investments	1	2
Deferred Compensation Plan Assets	9	8
Total	8	7
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] \| Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	10	8
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] \| Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		0
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] \| Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and gas derivative contracts	0	0
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] \| Commodity Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and gas derivative contracts	0	0
Significant Other Observable Fair Value Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund investments	0	0
Deferred Compensation Plan Assets	0	0
Total	994
Significant Other Observable Fair Value Inputs (Level 2) [Member] \| Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	0	0
Significant Other Observable Fair Value Inputs (Level 2) [Member] \| Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		0
Significant Other Observable Fair Value Inputs (Level 2) [Member] \| Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and gas derivative contracts	994
Significant Other Observable Fair Value Inputs (Level 2) [Member] \| Commodity Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and gas derivative contracts	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund investments	0	0
Deferred Compensation Plan Assets	0	0
Total		26
Fair Value, Inputs, Level 3 [Member] \| Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	0	0
Fair Value, Inputs, Level 3 [Member] \| Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		39
Fair Value, Inputs, Level 3 [Member] \| Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and gas derivative contracts	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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