Receivables (Details) (USD $) In Thousands, unless otherwise specified	Dec. 30, 2011	Sep. 30, 2011
Components of receivables:
Amounts billed	$ 1,013,658	$ 1,016,792
Unbilled receivables and other	955,693	996,516
Retentions receivable	57,622	64,186
Total receivables, net	2,026,973	2,077,494
Other information about receivables:
Amounts due from the United States federal government, included above, net of advanced billings	266,036	288,165
Claims receivable	$ 17,700	$ 14,712

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Amounts due for billed services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Company and, at a minimum, one other party. An example would be amounts billed to customers under contracts or programs but not paid as of the balance sheet date.

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Amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Entity and, at a minimum, one other party, which amounts are withheld by the contracting party pending the Entity's compliance or performance in conformity with the terms of the contract. Such billed but unpaid amounts are generally expected to be collected upon complying with certain contractual terms or satisfaction and release by the contracting party.

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Total amounts included within current and noncurrent receivables, billed or unbilled, under long-term contracts, which represent claims or other similar items subject to uncertainty concerning their determination or ultimate realization.

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Amounts due within 1 year (or 1 business cycle) from other related parties which are not otherwise stated in the taxonomy.

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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.

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Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

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