Goodwill and Intangibles, including DAC and VOBA, net - Estimated Amortization Expense for VOBA and DAC in Future Fiscal Periods (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014
Schedule Of Amortization Expense And Weighted Average Lives Of Identified Intangible Assets [Line Items]
2014	$ 77.5
2015	78.5
2016	78.5
2017	78.5
2018	78.5
VOBA
Schedule Of Amortization Expense And Weighted Average Lives Of Identified Intangible Assets [Line Items]
2014	42.8
2015	38.4
2016	31.2
2017	25.0
2018	25.5
2019 and thereafter	$ 88.1