Goodwill and Intangibles, including DAC and VOBA - Estimated Amortization Expense for VOBA and DAC in Future Fiscal Periods (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Schedule Of Amortization Expense And Weighted Average Lives Of Identified Intangible Assets [Line Items]
2013	$ 78.5
2014	78.5
2015	78.5
2016	78.5
2017	78.5
VOBA [Member]
Schedule Of Amortization Expense And Weighted Average Lives Of Identified Intangible Assets [Line Items]
2013	9.0
2014	45.7
2015	43.7
2016	39.5
2017	33.0
Thereafter	159.8
DAC [Member]
Schedule Of Amortization Expense And Weighted Average Lives Of Identified Intangible Assets [Line Items]
2013	4.5
2014	22.3
2015	23.6
2016	22.9
2017	22.0
Thereafter	$ 183.7