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Income Taxes (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017 | Mar. 31, 2018 | Mar. 31, 2017 | Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2017
Income Taxes |  |  |  |  |  |  |
Effective tax rate (as a percent) |  |  | 130.40% | (6.20%) |  |  |
Net benefit from Tax Cuts and Jobs Acts of 2017 |  |  | $ 41.7 |  |  |  |
Benefit from change in uncertain tax positions in US and Canada |  |  | 36.0 |  |  |  |
Benefit from income tax credits and incentives |  |  | 13.7 |  |  |  |
Amount of goodwill which was non-deductible for tax purposes | $ 33.9 |  | $ 33.9 |  |  |  |
Amount of uncertain tax positions for future years | $ 26.2 |  |  |  |  |  |
Federal statutory rate (as a percent) |  |  |  |  | 21.00% |  | 35.00%
Blended statutory rate (as a percentage) |  |  |  |  |  | 24.50% |
Provisional amount related to remeasurement of deferred tax balance |  | $ 36.1 |  |  |  |  |
Provisional amount of tax benefit related to releasing of deferred tax liability |  | 77.0 |  |  |  |  |
Provisional amount of income tax expense related to transition tax on foreign subsidiaries |  | $ 71.4 |  |  |  |  |
Gross book-tax differences from non-U.S. subsidiaries |  |  |  |  |  |  | $ 1,700.0

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- Definition The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in income tax contingencies. Including, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32698-109319 + Details
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