Income Taxes	3 Months Ended
Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes At the end of each interim reporting period, the Company makes an estimate of the annual effective income tax rate. Tax items included in the annual effective income tax rate are pro-rated for the full year and tax items discrete to a specific quarter are included in the effective income tax rate for that quarter. The estimate used in providing for income taxes on a year-to-date basis may change in subsequent interim periods. On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act (the Act). The Act amends the Internal Revenue Code to reduce tax rates and modify policies, credits and deductions for individuals and businesses. For businesses, the Act reduces the corporate federal tax rate from a maximum of 35.0 percent to a flat 21.0 percent rate and transitions from a worldwide tax system to a territorial tax system. The Act also adds many new provisions including changes to bonus depreciation, the deduction for executive compensation and interest expense, a tax on global intangible low-taxed income (GILTI), the base erosion anti-abuse tax (BEAT) and a deduction for foreign-derived intangible income (FDII). Many of these provisions, including the tax on GILTI, the BEAT and the deduction for FDII, do not apply to the Company until 2019. The Company is assessing the impact of the provisions of the Act which do not apply until 2019. The Company has elected to account for the tax on GILTI as a period cost and thus has not adjusted any of the deferred tax assets/liabilities of its foreign subsidiaries for the new tax. The two material items that impact the Company for 2018 are the reduction in the tax rate and a one-time tax that is imposed on the Company’s unremitted foreign earnings. On December 22, 2017, the SEC issued Staff Accounting Bulletin 118 that provides additional guidance allowing companies to use a measurement period, similar to that used in business combinations, to account for the impacts of the Act in their financial statements. The Company has accounted for the impacts of the Act to the extent a reasonable estimate could be made during the three months ended December 31, 2017. The Company will continue to refine its estimates throughout the measurement period or until the accounting is complete. Due to the Company’s fiscal year, the Company expects its 2018 U.S. federal statutory tax rate to be approximately 24.6 percent. The Company’s U.S. federal statutory tax rate will be 21.0 percent starting in 2019. As a result of the reduction in the U.S. corporate income tax rate from 35.0 percent to 21.0 percent under the Act, the Company has recorded a provisional reduction to its net deferred tax liability of $102 million, and a corresponding decrease to income tax expense in the Company’s Condensed Consolidated Statement of Operations for the three months ended December 31, 2017. The Company’s revaluation of its deferred tax liability is subject to further adjustments during the measurement period due to the complexity of determining its net deferred tax liability as of the enactment date. Some of the information necessary to determine the accounting impacts of the tax rate change includes final calculations related to the Company’s 2017 tax return as well as refining the analysis of which existing deferred balances at the enactment date will reverse in 2018 at the 24.6 percent tax rate and which deferred balances will reverse after 2018 at the 21.0 percent tax rate. As of the December 31, 2017 deemed repatriation date, the Company estimates that it had approximately $1.048 billion of unremitted foreign earnings that would be subject to the tax imposed under Section 965 of the Internal Revenue Code. The Act imposes a tax on these earnings at either a 15.5 percent rate or an 8.0 percent rate. The higher rate applies to the extent the Company's foreign subsidiaries have cash and cash equivalents at certain measurement dates, whereas the lower rate applies to any earnings that are in excess of the cash and cash equivalents balance. After accounting for foreign tax credits related to the deemed repatriated earnings, the Company estimates the tax to be approximately $75 million. The Company recorded a provisional amount of $40 million of tax expense in the Company’s Condensed Consolidated Statement of Operations for the three months ended December 31, 2017, and it has established a $35 million liability related to certain B/E Aerospace unremitted foreign earnings through purchase accounting. The Company’s accounting for the tax on unremitted foreign earnings is incomplete due to the complexity of determining the various components of the calculation. Some of the information necessary to determine the amount of the tax includes the future profitability of its foreign subsidiaries, cash balances as of September 30, 2018, and detailed tax computations that need to be completed as part of the Company’s 2017 tax return. During the three months ended December 31, 2017 and 2016, the effective income tax rate was (8.9) percent and 28.6 percent, respectively. The lower current year effective income tax rate was primarily due to a $102 million reduction in deferred tax liabilities resulting from enactment of the Act, a lower U.S. Federal statutory tax rate under the Act and benefits from the jurisdictional mix of income as a result of the B/E Aerospace acquisition, partially offset by a $40 million obligation related to the tax on unremitted foreign earnings imposed by the Act. The Company's U.S. Federal income tax returns for the tax year ended September 30, 2013 and prior years have been audited by the IRS and are closed to further adjustments. The IRS is currently auditing the Company's tax returns for the years ended September 30, 2014 and 2015. The IRS is currently auditing the legacy tax filings of an acquired subsidiary for the 2014 calendar year. The Company is also currently under audit in various U.S. states and non-U.S. jurisdictions. The U.S. states and non-U.S. jurisdictions have statutes of limitations generally ranging from 3 to 5 years. The Company believes it has adequately provided for any tax adjustments that may result from the various audits. The Company had net income tax payments of $7 million and $63 million during the three months ended December 31, 2017 and 2016, respectively. During the quarter, a provision of $35 million was recorded through purchase accounting related to approximately $250 million of B/E Aerospace’s pre-acquisition foreign earnings that the Company views as available for repatriation. The Company has gross unrecognized tax benefits recorded within Deferred Income Tax Liability and Other Liabilities in the Condensed Consolidated Statement of Financial Position of $214 million and $201 million as of December 31, 2017 and September 30, 2017, respectively. The total amount of unrecognized tax benefits that, if recognized, would affect the effective income tax rate was $183 million and $169 million as of December 31, 2017 and September 30, 2017, respectively. Although the timing and outcome of tax settlements are uncertain, it is reasonably possible that during the next 12 months a reduction in unrecognized tax benefits may occur in the range of $0 million to $49 million, based on the outcome of tax examinations or as a result of the expiration of various statutes of limitations. The Company includes interest and penalties related to unrecognized tax benefits in Income tax expense. The total amount of interest and penalties recognized within Other Liabilities in the Condensed Consolidated Statement of Financial Position was $9 million and $8 million as of December 31, 2017 and September 30, 2017, respectively. The total amount of interest and penalties recorded as an expense or (income) within Income tax expense in the Condensed Consolidated Statement of Operations were not significant for the three months ended December 31, 2017 and 2016, respectively.

Income Taxes

At the end of each interim reporting period, the Company makes an estimate of the annual effective income tax rate. Tax items included in the annual effective income tax rate are pro-rated for the full year and tax items discrete to a specific quarter are included in the effective income tax rate for that quarter. The estimate used in providing for income taxes on a year-to-date basis may change in subsequent interim periods.

On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act (the Act). The Act amends the Internal Revenue Code to reduce tax rates and modify policies, credits and deductions for individuals and businesses. For businesses, the Act reduces the corporate federal tax rate from a maximum of 35.0 percent to a flat 21.0 percent rate and transitions from a worldwide tax system to a territorial tax system. The Act also adds many new provisions including changes to bonus depreciation, the deduction for executive compensation and interest expense, a tax on global intangible low-taxed income (GILTI), the base erosion anti-abuse tax (BEAT) and a deduction for foreign-derived intangible income (FDII). Many of these provisions, including the tax on GILTI, the BEAT and the deduction for FDII, do not apply to the Company until 2019. The Company is assessing the impact of the provisions of the Act which do not apply until 2019. The Company has elected to account for the tax on GILTI as a period cost and thus has not adjusted any of the deferred tax assets/liabilities of its foreign subsidiaries for the new tax. The two material items that impact the Company for 2018 are the reduction in the tax rate and a one-time tax that is imposed on the Company’s unremitted foreign earnings.

On December 22, 2017, the SEC issued Staff Accounting Bulletin 118 that provides additional guidance allowing companies to use a measurement period, similar to that used in business combinations, to account for the impacts of the Act in their financial statements. The Company has accounted for the impacts of the Act to the extent a reasonable estimate could be made during the three months ended December 31, 2017. The Company will continue to refine its estimates throughout the measurement period or until the accounting is complete.

Due to the Company’s fiscal year, the Company expects its 2018 U.S. federal statutory tax rate to be approximately 24.6 percent. The Company’s U.S. federal statutory tax rate will be 21.0 percent starting in 2019.

As a result of the reduction in the U.S. corporate income tax rate from 35.0 percent to 21.0 percent under the Act, the Company has recorded a provisional reduction to its net deferred tax liability of $102 million, and a corresponding decrease to income tax expense in the Company’s Condensed Consolidated Statement of Operations for the three months ended December 31, 2017. The Company’s revaluation of its deferred tax liability is subject to further adjustments during the measurement period due to the complexity of determining its net deferred tax liability as of the enactment date. Some of the information necessary to determine the accounting impacts of the tax rate change includes final calculations related to the Company’s 2017 tax return as well as refining the analysis of which existing deferred balances at the enactment date will reverse in 2018 at the 24.6 percent tax rate and which deferred balances will reverse after 2018 at the 21.0 percent tax rate.

As of the December 31, 2017 deemed repatriation date, the Company estimates that it had approximately $1.048 billion of unremitted foreign earnings that would be subject to the tax imposed under Section 965 of the Internal Revenue Code. The Act imposes a tax on these earnings at either a 15.5 percent rate or an 8.0 percent rate. The higher rate applies to the extent the Company's foreign subsidiaries have cash and cash equivalents at certain measurement dates, whereas the lower rate applies to any earnings that are in excess of the cash and cash equivalents balance. After accounting for foreign tax credits related to the deemed repatriated earnings, the Company estimates the tax to be approximately $75 million. The Company recorded a provisional amount of $40 million of tax expense in the Company’s Condensed Consolidated Statement of Operations for the three months ended December 31, 2017, and it has established a $35 million liability related to certain B/E Aerospace unremitted foreign earnings through purchase accounting. The Company’s accounting for the tax on unremitted foreign earnings is incomplete due to the complexity of determining the various components of the calculation. Some of the information necessary to determine the amount of the tax includes the future profitability of its foreign subsidiaries, cash balances as of September 30, 2018, and detailed tax computations that need to be completed as part of the Company’s 2017 tax return.

During the three months ended December 31, 2017 and 2016, the effective income tax rate was (8.9) percent and 28.6 percent, respectively. The lower current year effective income tax rate was primarily due to a $102 million reduction in deferred tax liabilities resulting from enactment of the Act, a lower U.S. Federal statutory tax rate under the Act and benefits from the jurisdictional mix of income as a result of the B/E Aerospace acquisition, partially offset by a $40 million obligation related to the tax on unremitted foreign earnings imposed by the Act.

The Company's U.S. Federal income tax returns for the tax year ended September 30, 2013 and prior years have been audited by the IRS and are closed to further adjustments. The IRS is currently auditing the Company's tax returns for the years ended September 30, 2014 and 2015. The IRS is currently auditing the legacy tax filings of an acquired subsidiary for the 2014 calendar year. The Company is also currently under audit in various U.S. states and non-U.S. jurisdictions. The U.S. states and non-U.S. jurisdictions have statutes of limitations generally ranging from 3 to 5 years. The Company believes it has adequately provided for any tax adjustments that may result from the various audits.

The Company had net income tax payments of $7 million and $63 million during the three months ended December 31, 2017 and 2016, respectively. During the quarter, a provision of $35 million was recorded through purchase accounting related to approximately $250 million of B/E Aerospace’s pre-acquisition foreign earnings that the Company views as available for repatriation.

The Company has gross unrecognized tax benefits recorded within Deferred Income Tax Liability and Other Liabilities in the Condensed Consolidated Statement of Financial Position of $214 million and $201 million as of December 31, 2017 and September 30, 2017, respectively. The total amount of unrecognized tax benefits that, if recognized, would affect the effective income tax rate was $183 million and $169 million as of December 31, 2017 and September 30, 2017, respectively. Although the timing and outcome of tax settlements are uncertain, it is reasonably possible that during the next 12 months a reduction in unrecognized tax benefits may occur in the range of $0 million to $49 million, based on the outcome of tax examinations or as a result of the expiration of various statutes of limitations.

The Company includes interest and penalties related to unrecognized tax benefits in Income tax expense. The total amount of interest and penalties recognized within Other Liabilities in the Condensed Consolidated Statement of Financial Position was $9 million and $8 million as of December 31, 2017 and September 30, 2017, respectively. The total amount of interest and penalties recorded as an expense or (income) within Income tax expense in the Condensed Consolidated Statement of Operations were not significant for the three months ended December 31, 2017 and 2016, respectively.