XML 73 R33.htm IDEA: XBRL DOCUMENT v2.4.0.8
Investments (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Schedule of Investments [Line Items]        
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net $ 26.2 $ 3.8 $ 73.1 $ 20.6
Available-for-sale securities 19,491.0   19,491.0  
Accumulated net unrealized gains 476.6 862.2 476.6 862.2
Collateralized Mortgage-Backed Securities [Member]
       
Schedule of Investments [Line Items]        
Available-for-sale securities 2,714.3   2,714.3  
Asset-Backed Securities [Member]
       
Schedule of Investments [Line Items]        
Available-for-sale securities 341.8   341.8  
Sub-Prime Mortgage-Backed And Asset-Backed Securities [Member]
       
Schedule of Investments [Line Items]        
Available-for-sale securities 33.6   33.6  
Accumulated net unrealized gains 1.3   1.3  
Alt-A Mortgage-Backed And Asset-Backed Securities [Member]
       
Schedule of Investments [Line Items]        
Available-for-sale securities 108.4   108.4  
Accumulated net unrealized gains $ 6.1   $ 6.1