Acquisitions - Components of Net Deferred Tax Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Business Acquisition [Line Items]
Deferred tax assets,net	$ 293.4	$ 312.7
Deferred Tax Liabilities, Net	1,120.4	1,147.9
Deferred Tax Assets, Net	921.2	1,078.3
Business Acquisition Percentage Of Intangible Assets Acquired	19.60%
Subsidiaries One
Business Acquisition [Line Items]
Deferred Tax Assets Acquisition Costs	96.8
Deferred Tax Assets Insurance Reserve	401.7
Deferred Tax Assets, Operating Loss Carryforwards	128.4
Deferred Tax Assets, Capital Loss Carryforwards	267.5
Deferred Tax Assets, Tax Credit Carryforwards	75.2
Deferred Tax Assets, Other	24.1
Deferred Tax Assets, Gross	993.7
Deferred Tax Assets, Valuation Allowance	(405.4)
Deferred tax assets,net	588.3
Deferred Tax Liabilities Acquisition Cost	202.0
Deferred Tax Liabilities, Investments	121.2
Deferred Tax Liabilities, Other	12.4
Deferred Tax Liabilities, Net	335.6
Deferred Tax Assets, Net	$ 252.7