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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

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-Publisher FASB

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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

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-Topic 460

-SubTopic 10

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The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph a

-Article 5

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-Subparagraph (SX 210.5-02.3,4)

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- Definition

Number Of Major Customers

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No definition available.

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Fair Value Measurements (Details Guarantees and Credit Risk) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts and notes receivable
Receivables by product or service	1,139us-gaap_ReceivablesNetCurrent	674us-gaap_ReceivablesNetCurrent
Customer Concentration Risk [Member] \| Accounts receivable [Member]
Accounts and notes receivable
Receivables by product or service	308
Customer Concentration Risk [Member] \| Accounts receivable [Member] \| Williams Partners [Member]
Accounts and notes receivable
Number Of Major Customers - Receivables	1
Revenues
Number Of Major Customers - Revenues	1
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Williams Partners [Member]
Accounts and notes receivable
Number Of Major Customers - Receivables			1
Revenues
Number Of Major Customers - Revenues			1
Consolidated revenue, major customer, percentage	5.00%	9.00%	14.00%
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Access Midstream [Member]
Revenues
Consolidated revenue, major customer, percentage	9.00%
NGLs, natural gas, and related products and services [Member]
Accounts and notes receivable
Receivables by product or service	730	341
Transportation of natural gas and related products [Member]
Accounts and notes receivable
Receivables by product or service	175	193
Income tax receivable [Member]
Accounts and notes receivable
Receivables by product or service	167	74
Other Receivable [Member]
Accounts and notes receivable
Receivables by product or service	67	66
Wiltel Guarantee [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	34
Wpx Energy Inc [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	44