Basis for Presentation (Policies)	3 Months Ended
Dec. 31, 2017
Basis for Presentation
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Compensation — Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which changes how companies account for certain aspects of share-based payment awards to employees. We adopted the ASU in the first quarter of fiscal 2018. The updated guidance requires excess tax benefits and deficiencies from share-based payment awards to be recorded in income tax expense in the income statement. Previously, excess tax benefits and deficiencies were recognized in shareholders’ equity on the balance sheet. The guidance also requires classification of certain share-based payment activities within the statement of cash flows. These changes were applied prospectively but had no significant impact on our financial position, operating results or classification of cash flows. In May 2015, the FASB issued Accounting Standards Update ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). ASU 2015-07 removes the requirement to categorize investments for which the fair values are measured using the net asset value per share practical expedient within the fair value hierarchy. It also limits certain disclosures to investments for which the entity has elected to measure the fair value using the practical expedient. This guidance was adopted retrospectively in fiscal year 2017. The adoption did not have a material impact on our consolidated financial statements. On December 22, 2017, the U.S. government enacted tax legislation commonly referred to as the Tax Cuts and Jobs Act of 2017 (Tax Act). Also in December 2017, the Securities and Exchange Commission (SEC) staff issued Staff Accounting Bulletin 118, which provides guidance on accounting for the tax effects of the Tax Act for which the accounting under ASC 740 is incomplete. To the extent that a company's accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. As described in Note 10 below, at December 31, 2017, we have not completed our accounting for the tax effects of enactment of the Tax Act; however, in certain cases, we have made a reasonable estimate of the effects on our existing deferred tax balances and the one-time transition tax. Recent Accounting Pronouncements – Not Yet Adopted In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. ASU 2014-09 outlines a comprehensive revenue recognition model and supersedes most current revenue recognition guidance. The new guidance will require revenue to be recognized when promised goods or services are transferred to customers in amounts that reflect the consideration to which the company expects to be entitled in exchange for those goods or services. Adoption of the new rules could affect the timing of revenue recognition for certain transactions. Adoption of ASU 2014-09 will be required for us beginning in the first quarter of fiscal 2019 and we have determined that we will not adopt ASU 2014-09 earlier than required. ASU 2014-09 allows for two methods of adoption: (a) “full retrospective” adoption, meaning the standard is applied to all periods presented, or (b) “modified retrospective” adoption, meaning the cumulative effect of applying ASU 2014-09 is recognized as an adjustment to the opening retained earnings balance in the year of adoption. We have not yet determined which method of adoption we will select. We have assigned a task force within management to lead our implementation efforts and we have engaged outside advisors to assist. We are currently in the process of analyzing the impact of the adoption of the new standard on our various revenue streams. Under ASU 2014-09, revenue is recognized as control transfers to the customer. As such, revenue for our fixed-price development and production contracts will generally be recognized over time as costs are incurred, which is consistent with the revenue recognition model we currently use for the majority of these contracts. For certain of our fixed-price production contracts where we currently recognize revenue as units are delivered, in most cases the accounting for those contracts will change under ASU 2014-09 such that we will recognize revenue as costs are incurred. This change will generally result in an acceleration of revenue as compared with our current revenue recognition method for those contracts. Approximately 22% of our net sales used the units-of-delivery method to recognize revenue in fiscal 2017. We continue to analyze the impact of the new standard on our remaining revenue streams and, as the standard will supersede substantially all existing revenue guidance affecting us under GAAP, we expect that it will impact revenue and cost recognition on a significant number of our contracts across our business segments, in addition to our business processes and our information technology systems. Our process of evaluating the effect of the new standard will continue through fiscal year 2018. In January 2016, the FASB issued Accounting Standards Update ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10) which updates certain aspects of recognition, measurement, presentation and disclosure of financial instruments. ASU 2016-01 will be effective for us beginning October 1, 2018 and, with the exception of a specific portion of the amendment, early adoption is not permitted. We are currently evaluating the impact this guidance will have on our financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, Leases. Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases) at the commencement date: (a) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and (b) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The ASU will be effective for us beginning October 1, 2019 with early adoption permitted. ASU 2016-02 will be adopted on a modified retrospective transition basis for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments, which provides clarifying guidance on how entities should classify certain cash receipts and cash payments on the statement of cash flows. The guidance also clarifies how the predominance principle should be applied when cash receipts and cash payments have aspects of more than one class of cash flows. The guidance will be effective for us in our fiscal year beginning October 1, 2018, and early adoption is permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early. In October 2016, the FASB issued ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory, which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The guidance will be effective for us in our fiscal year beginning October 1, 2018, and early adoption is permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early. In November 2016, the FASB issued ASU 2016-18, Restricted Cash, which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. The guidance will be effective for us in our fiscal year beginning October 1, 2018, and early adoption is permitted. The adoption of this standard is anticipated to affect our presentation of restricted cash within our statement of cash flows. We are currently evaluating whether to adopt the new guidance early. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) Clarifying the Definition of a Business. This ASU clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance will be effective for us in our fiscal year beginning October 1, 2018 and early adoption is allowed for certain transactions. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment. This standard removes the second step of the goodwill impairment test, where a determination of the fair value of individual assets and liabilities of a reporting unit was needed to measure the goodwill impairment. Under this updated standard, goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The guidance will be effective for us in our fiscal year beginning October 1, 2020 with early adoption permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early. In March 2017, the FASB issued ASU 2017-07, Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The update requires employers to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. The other components of net benefit cost, including interest cost, expected return on plan assets, amortization of prior service cost/credit and actuarial gain/loss, and settlement and curtailment effects, are to be presented outside of any subtotal of operating income. Employers will have to disclose the line(s) used to present the other components of net periodic benefit cost, if the components are not presented separately in the income statement. ASU 2017-07 will be effective for us beginning October 1, 2018, and early adoption is permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early.

Recently Adopted Accounting Pronouncements

In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Compensation — Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which changes how companies account for certain aspects of share-based payment awards to employees. We adopted the ASU in the first quarter of fiscal 2018. The updated guidance requires excess tax benefits and deficiencies from share-based payment awards to be recorded in income tax expense in the income statement. Previously, excess tax benefits and deficiencies were recognized in shareholders’ equity on the balance sheet. The guidance also requires classification of certain share-based payment activities within the statement of cash flows. These changes were applied prospectively but had no significant impact on our financial position, operating results or classification of cash flows.

In May 2015, the FASB issued Accounting Standards Update ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). ASU 2015-07 removes the requirement to categorize investments for which the fair values are measured using the net asset value per share practical expedient within the fair value hierarchy. It also limits certain disclosures to investments for which the entity has elected to measure the fair value using the practical expedient. This guidance was adopted retrospectively in fiscal year 2017. The adoption did not have a material impact on our consolidated financial statements.

On December 22, 2017, the U.S. government enacted tax legislation commonly referred to as the Tax Cuts and Jobs Act of 2017 (Tax Act). Also in December 2017, the Securities and Exchange Commission (SEC) staff issued Staff Accounting Bulletin 118, which provides guidance on accounting for the tax effects of the Tax Act for which the accounting under ASC 740 is incomplete. To the extent that a company's accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. As described in Note 10 below, at December 31, 2017, we have not completed our accounting for the tax effects of enactment of the Tax Act; however, in certain cases, we have made a reasonable estimate of the effects on our existing deferred tax balances and the one-time transition tax.

Recent Accounting Pronouncements – Not Yet Adopted

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. ASU 2014-09 outlines a comprehensive revenue recognition model and supersedes most current revenue recognition guidance. The new guidance will require revenue to be recognized when promised goods or services are transferred to customers in amounts that reflect the consideration to which the company expects to be entitled in exchange for those goods or services. Adoption of the new rules could affect the timing of revenue recognition for certain transactions. Adoption of ASU 2014-09 will be required for us beginning in the first quarter of fiscal 2019 and we have determined that we will not adopt ASU 2014-09 earlier than required. ASU 2014-09 allows for two methods of adoption: (a) “full retrospective” adoption, meaning the standard is applied to all periods presented, or (b) “modified retrospective” adoption, meaning the cumulative effect of applying ASU 2014-09 is recognized as an adjustment to the opening retained earnings balance in the year of adoption. We have not yet determined which method of adoption we will select.

We have assigned a task force within management to lead our implementation efforts and we have engaged outside advisors to assist. We are currently in the process of analyzing the impact of the adoption of the new standard on our various revenue streams. Under ASU 2014-09, revenue is recognized as control transfers to the customer. As such, revenue for our fixed-price development and production contracts will generally be recognized over time as costs are incurred, which is consistent with the revenue recognition model we currently use for the majority of these contracts. For certain of our fixed-price production contracts where we currently recognize revenue as units are delivered, in most cases the accounting for those contracts will change under ASU 2014-09 such that we will recognize revenue as costs are incurred. This change will generally result in an acceleration of revenue as compared with our current revenue recognition method for those contracts. Approximately 22% of our net sales used the units-of-delivery method to recognize revenue in fiscal 2017. We continue to analyze the impact of the new standard on our remaining revenue streams and, as the standard will supersede substantially all existing revenue guidance affecting us under GAAP, we expect that it will impact revenue and cost recognition on a significant number of our contracts across our business segments, in addition to our business processes and our information technology systems. Our process of evaluating the effect of the new standard will continue through fiscal year 2018.

In January 2016, the FASB issued Accounting Standards Update ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10) which updates certain aspects of recognition, measurement, presentation and disclosure of financial instruments. ASU 2016-01 will be effective for us beginning October 1, 2018 and, with the exception of a specific portion of the amendment, early adoption is not permitted. We are currently evaluating the impact this guidance will have on our financial statements and related disclosures.

In February 2016, the FASB issued ASU 2016-02, Leases. Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases) at the commencement date: (a) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and (b) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The ASU will be effective for us beginning October 1, 2019 with early adoption permitted. ASU 2016-02 will be adopted on a modified retrospective transition basis for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early.

In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments, which provides clarifying guidance on how entities should classify certain cash receipts and cash payments on the statement of cash flows. The guidance also clarifies how the predominance principle should be applied when cash receipts and cash payments have aspects of more than one class of cash flows. The guidance will be effective for us in our fiscal year beginning October 1, 2018, and early adoption is permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early.

In October 2016, the FASB issued ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory, which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The guidance will be effective for us in our fiscal year beginning October 1, 2018, and early adoption is permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early.

In November 2016, the FASB issued ASU 2016-18, Restricted Cash, which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. The guidance will be effective for us in our fiscal year beginning October 1, 2018, and early adoption is permitted. The adoption of this standard is anticipated to affect our presentation of restricted cash within our statement of cash flows. We are currently evaluating whether to adopt the new guidance early.

In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) Clarifying the Definition of a Business. This ASU clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance will be effective for us in our fiscal year beginning October 1, 2018 and early adoption is allowed for certain transactions. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements.

In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment. This standard removes the second step of the goodwill impairment test, where a determination of the fair value of individual assets and liabilities of a reporting unit was needed to measure the goodwill impairment. Under this updated standard, goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The guidance will be effective for us in our fiscal year beginning October 1, 2020 with early adoption permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early.

In March 2017, the FASB issued ASU 2017-07, Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The update requires employers to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. The other components of net benefit cost, including interest cost, expected return on plan assets, amortization of prior service cost/credit and actuarial gain/loss, and settlement and curtailment effects, are to be presented outside of any subtotal of operating income. Employers will have to disclose the line(s) used to present the other components of net periodic benefit cost, if the components are not presented separately in the income statement. ASU 2017-07 will be effective for us beginning October 1, 2018, and early adoption is permitted. We are currently evaluating the impact of the application of this accounting standard update on our consolidated financial statements as well as whether to adopt the new guidance early.