v2.4.0.6
Debt (Junior Convertible Subordinated Debentures) (Details) (USD $)
Share data in Millions, except Per Share data, unless otherwise specified
 12 Months Ended 24 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2011
Junior Subordinated Debt [Member]
Dec. 31, 2011
Convertible Preferred Stock [Member]
Dec. 31, 2005
Convertible Preferred Stock [Member]
Finance subsidiary ownership percentage     100.00%    
Issued shares of convertible preferred securities       10.0  
Preferred Stock, Dividend Rate, Percentage       5.25%  
Convertible Preferred Securities, Par Value Per Share       $ 50  
Convertible Preferred Securities, Dividend Amount Per Share       $ 2.625  
Interest rate of junior subordinated debt     5.25%    
Junior Subordinated Debentures, Redeemable Date     Dec. 01, 2001    
Interest Payment Deferral Period at Entity's Option, Max     20    
Incremental Debentures Issued to Unconsolidated Subsidary     15,500,000    
Junior Subordinated Debentures Owed to Unconsolidated Subsidiary, Issued     515,500,000    
Preferred securities convertible into common stock       0.9865  
Convertible Preferred Securities, Shares Repurchased         1.6
Convertible Preferred Securities, Shares Repurchased, Price Per Share         $ 45.27
Convertible Preferred Securities, Shares Repurchased, Amount         71,300,000
Preferred securities issued unconditionally guarantees       8.4  
Percentage of liquidation preference payable when called       100.00%  
Liquidation preference on preferred stock       421,200,000  
Maturity date of junior convertible subordinated debentures     Dec. 01, 2027    
Outstanding debentures $ 436,700,000 $ 436,700,000