Income Taxes	6 Months Ended
Income Taxes	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (“Tax Act”). The Tax Act significantly revised the U.S. federal corporate income tax provisions, including, but not limited to, an income inclusion of global intangible low-taxed income (“GILTI”), a deduction against foreign-derived intangible income (“FDII”) and a new minimum tax, the base erosion anti-abuse tax (“BEAT”). GILTI, FDII and BEAT were effective for the Company’s fiscal year ending September 30, 2019. The Company has elected to recognize the GILTI impact in the specific period in which it occurs. As a result of final regulations regarding the interest expense allocation rules issued by the Internal Revenue Service in December 2019, the Company concluded that it is more likely than not that the entire amount of the Company’s deferred tax assets relating to foreign tax credit carryforwards will be realized. Consequently, the Company released its $33 million valuation allowance at September 30, 2019 relating to such deferred tax assets and recognized a corresponding U.S. tax benefit of $33 million during the three months ended December 31, 2019. The Company will continue to weigh the evidence including the projections of sufficient future taxable income, foreign source income and the reversal of future taxable temporary differences to assess the future realization of our foreign tax credits. As a result of the IPO in June 2020, the Company is subject to limitation on the deductibility of executive compensation under Internal Revenue Code (“IRC”) Section 162(m). For the three and six months ended March 31, 2021, the Company recorded an income tax expense of $51 million and $86 million, respectively. The income tax expense for the three months ended March 31, 2021 is higher than the expected tax expense at the statutory tax rate of 21% primarily due to U.S. state and local taxes, foreign income taxes at rates higher than the U.S., and non-deductible executive compensation under IRC Section 162(m), offset, by FDII. The income tax expense for the six months ended March 31, 2021 is higher than the expected tax expense at the statutory tax rate of 21% primarily due to U.S. state and local taxes, foreign income taxes at rates higher than the U.S., and non-deductible executive compensation under IRC Section 162(m), offset by FDII and excess tax benefits from long term incentive plan. For the three and six months ended March 31, 2020, the Company recorded an income tax benefit of $12 million and $7 million, respectively. The income tax benefit for the three months ended March 31, 2020 is lower than the expected tax benefit at the statutory tax rate of 21% primarily due to non-deductible expenses of the Plan. The income tax benefit for the six months ended March 31, 2020 is lower than the expected tax benefit at the statutory rate of 21% primarily due to tax benefit of the valuation allowance release relating to foreign tax credit carryforwards and FDII, offset by non-deductible expenses of the Plan, U.S. state and local taxes, foreign income taxed at rates higher than the U.S. statutory tax rate, withholding taxes and foreign losses with no tax benefit. The Company has determined that it is reasonably possible that the gross unrecognized tax benefits as of March 31, 2021 could decrease by up to approximately $2 million related to various ongoing audits and settlement discussions in various foreign jurisdictions during the next twelve months.

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.