The increase (decrease) during the period impacting the parent's ownership interest in a subsidiary as it relates to the total (consolidated) equity attributable to the parent. The changes to the parent's ownership interest in a subsidiary represented by this element did not arise in a deconsolidation of the subsidiary from the consolidated financial statements.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4M

-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591554-111686

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- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

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- Definition

The tax effect of items occurring during the period that have been charged or credited directly to components of shareholders' equity and are not otherwise defined.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 20

-Section 45

-Paragraph 11

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The number of units or percentage investment held by one or more members or limited partners of the LLC or LP.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

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General, Description of Business, and Basis of Presentation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	2 Months Ended	0 Months Ended
	Mar. 31, 2015	Mar. 31, 2015	Feb. 02, 2015
Schedule of Equity Method Investments [Line Items]
Number Of Interstate Natural Gas Pipelines	2
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	$ (97)
Constitution Pipeline Company LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage	41.00%
General and Limited Partner [Member] \| Williams Partners L. P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Master limited partnership, ownership percentage	60.00%
General and Limited Partner [Member] \| Williams Partners L. P. [Member] \| Merger [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Master limited partnership, ownership percentage		60.00%
ACMP Units Into Merged Partnership Units [Member] \| Williams Partners L. P. [Member] \| Merger [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Conversion Ratio			1.06152
Publicly Held WPZ Common Units into ACMP Common Units [Member] \| Williams Partners L. P. [Member] \| Merger [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Conversion Ratio			0.86672
Privately Held WPZ Units Into ACMP Common Units [Member] \| Williams Partners L. P. [Member] \| Merger [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Conversion Ratio			0.80036
Class D WPZ Units Into WPZ Common Units [Member] \| Williams Partners L. P. [Member] \| Merger [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Conversion Ratio			1
Capital in Excess of Par Value
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	163
Noncontrolling Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	(260)
Deferred Income Taxes [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Income Tax Effects Allocated Directly to Equity, Other	$ 97
Gulfstream Natural Gas System, L.L.C.[Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%	50.00%
Utica East Ohio Midstream, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	49.00%	49.00%
Delaware Basin Gas Gathering System [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%	50.00%
Laurel Mountain Midstream, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	69.00%	69.00%
Caiman Energy II [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	58.00%	58.00%
Discovery Producer Services LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	60.00%	60.00%
Overland Pass Pipeline Company LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%	50.00%
Appalachia Midstream Services, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	45.00%	45.00%
Number of Gathering Systems	11