Income Taxes Effective Tax Rate Reconciliation (Parenthetical) (Details) $ in Millions	12 Months Ended
Sep. 30, 2018 USD ($)
Income Tax Disclosure [Abstract]
Benefit from the remeasurement of our net U.S. deferred tax liability	$ 1,215.9
One-time transition liability	95.4
Tax Cuts and Jobs Act Of 2017 one-time transition liability net of the release of a previously recorded outside basis difference	$ 87.1

Amount of income tax benefit for remeasurement of deferred tax liability from change in tax rate pursuant to Tax Cuts and Jobs Act.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

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Period Type:	duration