Divestitures - Schedule of Assets and Liabilities of Business Held for Sale (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 758.8	$ 270.1	$ 294.6	$ 465.2
Disposal Group, Including Discontinued Operation, Assets, Current	1,976.0	28,929.2
Other receivables, net	337.6	266.0
Deferred charges and other assets	60.8	43.7
Long Term Debt Current And Non Current	5,318.7	5,705.1
Accounts Payable and Accrued Liabilities, Current	360.7	373.1
Other long-term liabilities	101.1	26.2
Disposal Group, Including Discontinued Operation, Liabilities, Current	558.6	26,851.3
Consumer Products Segment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	214.6	260.1
Disposal Group, Including Discontinued Operation, Other Assets, Current	25.2	24.0
Disposal Group, Including Discontinued Operation, Assets, Current	1,976.0	1,979.9
Disposal Group, Including Discontinued Operation, Current portion of long-term debt	28.3	17.3
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	250.8	355.9
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	31.9	37.6
Disposal Group, Including Discontinued Operation, Other Liabilities, Current	90.4	89.8
Disposal Group, Including Discontinued Operation, Debt	52.6	51.7
Deferred Income Tax Liabilities, Net	38.7	38.2
Disposal Group, Including Discontinued Operation, Inventory, Current	324.7	279.2
Disposal Group, Including Discontinued Operation, Prepaid and Other Assets	41.9	39.7
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Current	198.1	196.8
Disposal Group, Including Discontinued Operation, Deferred Revenue, Current	17.8	19.3
Disposal Group, Including Discontinued Operation, Goodwill, Current	351.3	348.9
Disposal Group, Including Discontinued Operation, Intangible Assets, Current	802.4	811.9
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent	65.9	66.2
Disposal Group, Including Discontinued Operation, Liabilities, Current	$ 558.6	656.7
Insurance Segment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Investment		23,211.1
Disposal Group, Including Discontinued Operations, Funds Withheld Receivables		742.7
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents		914.5
Disposal Group, Including Discontinued Operation, Accrued Investment Income		231.3
Disposal Group, Including Discontinued Operation, Reinsurance Recoverable		2,358.8
Disposal Group, Including Discontinued Operation, Intangible Assets		1,163.6
Disposal Group, Including Discontinued Operation, Other Assets		125.4
Disposal Group, Including Discontinued Operation, Write-down of assets held for sale to fair value less costs to sell		(421.2)
Disposal Group, Including Discontinued Operation, Assets		28,326.2
Disposal Group, Including Discontinued Operation, Insurance Reserves		24,989.6
Disposal Group, Including Discontinued Operation, Debt		405.0
Disposal Group, Including Discontinued Operation, Accounts Payable and Accrued Liabilities		56.2
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities, Current		68.0
Disposal Group, Including Discontinued Operation, Other Liabilities		831.9
Disposal Group, Including Discontinued Operation, Liabilities		26,350.7
FGL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Write-down of assets held for sale to fair value less costs to sell		$ 402.2