2.4.0.8100160 - Disclosure - Description of Business and Basis of Presentation (Policies)truefalsefalse1false falsefalseC_0001483096_20130101_20130630http://www.sec.gov/CIK0001483096duration2013-01-01T00:00:002013-06-30T00:00:001false 4acmp_OrganizationPolicyTextBlockacmp_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div> Organization Access Midstream Partners, L.P. (the “Partnership”), a Delaware limited partnership formed in January 2010, is principally focused on natural gas gathering, the first segment of midstream energy infrastructure that connects natural gas produced at the wellhead to third-party takeaway pipelines. The Partnership is the industry’s largest gathering and processing master limited partnership as measured by throughput volume. The Partnership’s assets are located in Arkansas, Kansas, Louisiana, Maryland, New York, Ohio, Oklahoma, Pennsylvania, Texas, Virginia, West Virginia and Wyoming. The Partnership provides gathering, treating and compression services to Chesapeake Energy Corporation (“Chesapeake”), Total Gas and Power North America, Inc. (“Total”), Statoil ASA (“Statoil”), Anadarko Petroleum Corporation (“Anadarko”), Mitsui & Co., Ltd. (“Mitsui”) and other producers under long-term, fixed-fee contracts. For purposes of these financial statements, the “GIP I Entities” refers to, collectively, GIP-A Holding (CHK), L.P., GIP-B Holding (CHK), L.P. and GIP-C Holding (CHK), L.P., the “GIP II Entities” refers to certain entities affiliated with Global Infrastructure Investors II, LLC, and “GIP” refers to the GIP I Entities and their affiliates and the GIP II Entities, collectively. “Williams” refers to The Williams Companies, Inc. (NYSE: WMB). </div>falsefalsefalsenonnum:textBlockItemTypenaOrganization Policy [Text Block]No definition available.false0Organization2false 4us-gaap_BusinessCombinationsPolicyus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div> Acquisition On December 20, 2012, the Partnership acquired from Chesapeake Midstream Development, L.P. (“CMD”), a wholly owned subsidiary of Chesapeake, and certain of CMD’s affiliates, 100 percent of the issued and outstanding equity interests in Chesapeake Midstream Operating, L.L.C. (“CMO”) for total consideration of $2.16 billion (the “CMO Acquisition”). As a result of the CMO Acquisition, the Partnership now owns certain midstream assets in the Eagle Ford, Utica and Niobrara regions. The CMO Acquisition also extended the Partnership’s assets and operations in the Haynesville, Marcellus and Mid-Continent regions. The acquired assets included, in the aggregate, approximately 1,675 miles of pipeline and 4.3 million (gross) dedicated acres as of the date of the acquisition. The Partnership also assumed various gas gathering and processing agreements associated with the assets that have terms ranging from 10 to 20 years and that, in certain cases, include cost of service or fee redetermination mechanisms. Concurrently with the CMO Acquisition, the GIP I Entities sold to Williams 34,538,061 of the Partnership’s subordinated units and 50% of the outstanding equity interests in Access Midstream Ventures, L.L.C., the sole member of the Partnership’s general partner, for cash consideration of approximately $1.8 billion (the “Williams Acquisition”). The Partnership did not receive any cash proceeds from the Williams Acquisition. As a result of the closing of the Williams Acquisition, the GIP II Entities and Williams together own and control the Partnership’s general partner and the GIP I Entities no longer have any ownership interest in the Partnership or its general partner. Equity Issuance On April 2, 2013, the Partnership completed an equity offering of 10.35 million common units, including 1.35 million common units issued pursuant to the underwriters’ exercise of their option to purchase additional common units, at a price of $39.86 per common unit. The Partnership received offering proceeds (net of underwriting discounts and commissions) of $400.1 million from the equity offering, including proceeds from the underwriters’ exercise of their option to purchase additional common units and an approximate $8.4 million capital contribution from the Partnership’s general partner to maintain its two percent general partner interest. The proceeds were used for general partnership purposes, including repayment of amounts outstanding under the Partnership’s revolving credit facility. On December 18, 2012, the Partnership completed an equity offering of 18.4 million common units, including 2.4 million common units issued pursuant to the exercise of the underwriters’ option to purchase additional common units, at a price of $32.15 per common unit. The Partnership received offering proceeds (net of underwriting discounts, commissions and offering expenses) of approximately $569.3 million from the equity offering, including proceeds from the underwriters’ exercise of their option to purchase additional common units. The Partnership used the net proceeds to pay a portion of the purchase price for the CMO Acquisition. Subscription Agreement On December 20, 2012, the Partnership sold 5.9 million Class B units to each of the GIP II Entities and Williams and 5.6 million Class C units to each of the GIP II Entities and Williams, in each case pursuant to the subscription agreement. The Partnership received aggregate proceeds of approximately $712.1 million in exchange for the sale of Class B units and Class C units, inclusive of the capital contribution made by the general partner to maintain its two percent interest in the Partnership following the issuance of common, Class B and Class C units. </div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for completed business combinations (purchase method, acquisition method or combination of entities under common control). This accounting policy may include a general discussion of the purchase method or acquisition method of accounting (including for example, the treatment accorded contingent consideration, the identification of assets and liabilities, the purchase price allocation process, how the fair values of acquired assets and liabilities are determined) and the entity's specific application thereof. An entity that acquires another entity in a leveraged buyout transaction generally discloses the accounting policy followed by the acquiring entity in determining the basis used to value its interest in the acquired entity, and the rationale for that accounting policy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -URI http://asc.fasb.org/subtopic&trid=2303973 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 05 -Paragraph 4 -Subparagraph (a)-(d) -URI http://asc.fasb.org/extlink&oid=6909625&loc=d3e227-128457 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 6 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 7 -Subparagraph a, b, c, d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 88-16 -Section SEC Observer Comments -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 9, 10, 11, 12, 13 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Acquisition3false 4us-gaap_InterestInUnincorporatedJointVenturesOrPartnershipsPolicyus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div> Holdings of Partnership Capital At June 30, 2013, the GIP II Entities held 2,042,458 notional general partner units representing a 1.0 percent general partner interest in the Partnership, 50.0 percent of the Partnership’s incentive distribution rights, 33,704,666 common units, 34,538,061 subordinated units, 6,080,365 Class B units and 5,599,634 Class C units. The GIP II Entities’ ownership represents an aggregate 39.1 percent limited partner interest in the Partnership. Williams held 2,042,458 notional general partner units representing a 1.0 percent general partner interest in the Partnership, 50.0 percent of the Partnership’s incentive distribution rights, 34,538,061 subordinated units, 6,080,365 Class B units and 5,599,634 Class C units. Williams ownership represents an aggregate 22.6 percent limited partner interest in the Partnership. The public held 74,020,115 common units, representing a 36.3 percent limited partner interest in the Partnership. </div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for interest in an unincorporated joint venture or partnership that is included in the enterprise's financial statements using the proportionate consolidation method of accounting.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 323 -URI http://asc.fasb.org/subtopic&trid=2145602 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 19 -Paragraph 59I -Subparagraph b -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Holdings of Partnership Capital4false 4us-gaap_BasisOfAccountingPolicyPolicyTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div> Basis of Presentation The accompanying financial statements and related notes present the unaudited condensed consolidated balance sheets of the Partnership as of June 30, 2013 and December 31, 2012. They also include the unaudited condensed consolidated statements of operations for the three and six-month periods ended June 30, 2013 and 2012, the unaudited condensed consolidated statements of cash flows for the Partnership for the six-month periods ended June 30, 2013 and 2012, and the unaudited changes in partners’ capital of the Partnership for the six-month period ended June 30, 2013. The accompanying condensed consolidated financial statements were prepared using accounting principles generally accepted in the United States (“GAAP”) for interim financial information and in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”). In the opinion of management, the interim data includes all adjustments, consisting only of normal recurring adjustments, necessary to a fair statement of the results for the interim periods. Certain footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been appropriately condensed or omitted in this quarterly report on Form 10-Q (this “Form 10-Q”). Management believes the disclosures made are adequate to make the information presented not misleading. This Form 10-Q should be read together with the Partnership’s annual report on Form 10-K for the year ended December 31, 2012. The results of operations for the six-month period ended June 30, 2013, are not indicative of results that may be expected for the full fiscal year. Certain reclassifications have been made to prior period amounts to conform to the current period financial statement presentation. </div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS).No definition available.false0Basis of PresentationfalseDescription of Business and Basis of Presentation (Policies)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.accessmidstream.com/20130630/taxonomy/role/DisclosureDescriptionOfBusinessAndBasisOfPresentationPolicies14