Summary of Significant Accounting Policies (Policies)

3 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Consolidation Policy Text Block

The accompanying financial statements present the consolidated financial position, results of operations and cash flows of AmerisourceBergen Corporation and its wholly owned subsidiaries (the “Company”) as of the dates and for the periods indicated. All intercompany accounts and transactions have been eliminated in consolidation.

Basis of Accounting [Text Block]

The accompanying unaudited consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) for interim financial information, the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. In the opinion of management, all adjustments (consisting only of normal recurring accruals, except as otherwise disclosed herein) considered necessary to present fairly the financial position as of December 31, 2011 and the results of operations and cash flows for the interim periods ended December 31, 2011 and 2010 have been included. Certain information and footnote disclosures normally included in financial statements presented in accordance with U.S. GAAP, but which are not required for interim reporting purposes, have been omitted. The accompanying unaudited consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2011.

Use of Estimates, Policy [Policy Text Block]

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Actual amounts could differ from these estimated amounts.

Segment Reporting Disclosure Text Block

The Company has three operating segments, which include the operations of AmerisourceBergen Drug Corporation (“ABDC”), AmerisourceBergen Specialty Group (“ABSG”), and AmerisourceBergen Consulting Services (“ABCS”). The Company has aggregated the operating results of all of its operating segments into one reportable segment, Pharmaceutical Distribution, which represents the consolidated operating results of the Company. The businesses of the Pharmaceutical Distribution operating segments are similar in that they service both healthcare providers and pharmaceutical manufacturers in the pharmaceutical supply channel.