Schedule of deferred income tax assets and liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred Acquisition Cost	$ 70.0	$ 39.3
Deferred Tax Liabilities, Property, Plant and Equipment	80.3	74.1
Deferred Tax Liabilities, Investments	1,274.3	2,342.8
Other	54.4	63.2
Gross Deferred Tax Liability	1,479.0	2,519.4
Invested Assets	1,180.1	1,934.2
Employee Benefits	151.2	315.2
Other	3.4	0.6
Gross Deferred Tax Asset	1,334.7	2,250.0
Total Net Deferred Tax Liability	$ 144.3	$ 269.4