Divestitures (Summary Of Components Of Income From HRG Insurance Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from discontinued operations before income taxes	$ 959.3	$ 15.8	$ 865.9	$ 521.6
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues				378.6
Total operating costs and expenses				329.9
Operating (loss) income				48.7
Interest expense and other				4.0
Write-down of assets of business held for sale to fair value less cost to sell				(14.2)
Reclassification of accumulated other comprehensive income				445.9
Income (Loss) from discontinued operations before income taxes				476.4
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Net Investment Income [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues				181.9
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Net Investment Gains [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues				154.8
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Other Revenue [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues				35.1
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Benefits And Other Changes In Policy Reserves [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total operating costs and expenses				241.3
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Selling, Acquisition, Operating And General Expenses [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total operating costs and expenses				52.8
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Amortization Of Intangibles [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total operating costs and expenses				35.8
Discontinued Operations, Held-For-Sale [Member] | HRG Insurance Operations [Member] | Insurance Premiums [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues				$ 6.8