Divestitures Divestitures - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Document Fiscal Year Focus	2017
Document Period End Date	Dec. 31, 2016
FGL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred Tax Assets, Valuation Allowance		$ 247.7
Discontinued Operation, Tax Effect of Discontinued Operation, Deferred Taxes, Current		90.9
Deferred Tax Liabilities, Parent's Basis in Discontinued Operation		338.6
Business Acquisition, Termination Fee Payable for Termination of Merger Agreement	$ 51.5
Disposal Group, Including Discontinued Operation, Write-down of assets held for sale to fair value less costs to sell	(218.3)		$ (362.8)
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	$ (144.5)	$ 0.0
FGL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage Of Ownership Interest	80.50%