Basis of Presentation, Significant Accounting Polices and Practicies and Recent Accounting Pronouncements Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Jan. 13, 2017	Sep. 30, 2016
Basis of Presentation [Line Items]
Earnings Per Share, Diluted	$ 1.06	$ (0.17)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	1.19	(0.06)
Income (Loss) from Continuing Operations, Per Diluted Share	(0.13)	(0.11)
Earnings Per Share, Basic	1.06	(0.17)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	1.19	(0.06)
Income (Loss) from Continuing Operations, Per Basic Share	$ (0.13)	$ (0.11)
Net Income (Loss) Attributable to Parent	$ 212.2	$ (33.9)
Less: Net income attributable to noncontrolling interest	48.6	40.9
Net income	260.8	7.0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	258.8	(2.5)
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	2.0	9.5
Income tax expense (benefit)	$ 25.4	$ (5.6)
Document Period End Date	Dec. 31, 2016
Deferred Finance Costs, Net	$ 82.2			$ 87.0
FGL [Member]
Basis of Presentation [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	19.50%
Raven Re [Member]
Basis of Presentation [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 195.0			201.3
Statutory Accounting Practices, Permitted Practice, Change in Statutory Capital and Surplus	4.0			4.2
Statutory Accounting Practices, Non-Permitted Practice, Change in Statutory Capital and Surplus	(8.3)			(4.6)
Statutory Accounting Practices, Statutory Capital and Surplus, Change in Permitted Practice to Non-Permitted, Balance	$ 207.3			$ 210.0
Secured Debt [Member] | Subsequent Event [Member] | Margin Loan, due July 13, 2018 [Member]
Basis of Presentation [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 150.0