Income Taxes	3 Months Ended
Income Taxes	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes At the end of each interim period, we estimate a base effective tax rate that we expect for the full fiscal year based on our most recent forecast of pre-tax income, permanent book and tax differences and global tax planning strategies. We use this base rate to provide for income taxes on a year-to-date basis, excluding the effect of significant unusual items and items that are reported net of their related tax effects in the period in which they occur. The effective tax rate was 15.8 percent in the three months ended December 31, 2020, compared to 5.7 percent in the three months ended December 31, 2019. The effective tax rate was lower than the U.S. statutory rate of 21 percent in the three months ended December 31, 2020, primarily due to PTC investment adjustments and because we benefited from lower non-U.S. tax rates. The effective tax rate was lower than the U.S. statutory rate of 21 percent in the three months ended December 31, 2019, primarily due to PTC investment adjustments, tax benefits recognized upon the formation of the Sensia joint venture, and excess income tax benefits of share-based compensation. An income tax liability of $296.0 million related to the U.S. transition tax under the Tax Act that is payable greater than 12 months after both December 31, 2020, and September 30, 2020, is recorded in other liabilities in the Consolidated Balance Sheet. Unrecognized Tax Benefits The amount of gross unrecognized tax benefits was $22.5 million and $25.5 million at December 31, 2020, and September 30, 2020, respectively, of which the entire amount would reduce our effective tax rate if recognized. Accrued interest and penalties related to unrecognized tax benefits were $4.2 million and $4.0 million at December 31, 2020, and September 30, 2020, respectively. We recognize interest and penalties related to unrecognized tax benefits in the income tax provision. We believe it is reasonably possible that the amount of gross unrecognized tax benefits could be reduced by up to $22.1 million in the next 12 months as a result of the resolution of tax matters in various global jurisdictions and the lapses of statutes of limitations. If all of the unrecognized tax benefits were recognized, the net reduction to our income tax provision, including the recognition of interest and penalties and offsetting tax assets, could be up to $25.6 million. We conduct business globally and are routinely audited by the various tax jurisdictions in which we operate. We are no longer subject to U.S. federal income tax examinations for years before 2016 and are no longer subject to state, local and foreign income tax examinations for years before 2009.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.