Divestitures Divestitures - Schedule of assets and liabilities held for sale (Details) - FGL [Member] - USD ($) $ in Millions	Mar. 31, 2016	Sep. 30, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Investment	$ 19,697.1	$ 19,206.7
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	496.4	501.8
Disposal Group, Including Discontinued Operation, Accrued Investment Income	208.5	191.2
Disposal Group, Including Discontinued Operation, Reinsurance Recoverable	3,511.7	3,578.7
Disposal Group, Including Discontinued Operation, Deferred Tax Assets	191.0	194.7
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	15.9	14.4
Disposal Group, Including Discontinued Operation, Intangible Assets	1,234.3	1,048.6
Disposal Group, Including Discontinued Operation, Other Assets	212.6	248.4
Disposal Group, Including Discontinued Operation, Write-down of assets held for sale to fair value less costs to sell	(23.5)	0.0
Disposal Group, Including Discontinued Operation, Assets [Abstract]
Disposal Group, Including Discontinued Operation, Assets	25,544.0	24,984.5
Disposal Group, Including Discontinued Operation, Insurance Reserves	23,018.8	22,560.1
Disposal Group, Including Discontinued Operation, Debt	300.0	298.3
Disposal Group, Including Discontinued Operation, Accounts Payable and Accrued Liabilities	46.4	43.7
Disposal Group, Including Discontinued Operation, Other Liabilities	622.9	518.8
Disposal Group, Including Discontinued Operation, Liabilities	$ 23,988.1	$ 23,420.9