v2.4.0.8
Borrowings (Details) (USD $)
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum 4.20%    
Repayments of Long-term Debt $ 10,500,000 $ 1,511,100,000 $ 61,700,000
Notes Payable 4,887,300,000 4,887,300,000  
Other Notes Payable 27,100,000 37,400,000  
Long-term Debt, Fair Value Adjustment 298,500,000 606,600,000  
Long-term Debt, Total 5,212,900,000 5,531,300,000  
Long-term Debt, Current Maturities (1,012,600,000) (11,900,000)  
Long-term debt 4,200,300,000 5,519,400,000  
Description of Derivative Activity Volume Percent 65.00%    
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 1,010,000,000    
Long-term Debt, Maturities, Repayments of Principal in Year Two 9,500,000    
Long-term Debt, Maturities, Repayments of Principal in Year Three 205,600,000    
Long-term Debt, Maturities, Repayments of Principal in Year Four 1,000,000,000    
Long-term Debt, Maturities, Repayments of Principal in Year Five 200,300,000    
Line of Credit Facility, Remaining Borrowing Capacity 1,360,000,000    
Line of Credit Facility, Collateral, Amount 1,200,000,000    
Line of Credit Facility, Amount Outstanding 0    
Interest Paid, Net $ 139,700,000 $ 171,900,000 $ 167,400,000
Debt Instrument, Interest Rate, Effective Percentage 3.10% 3.20%  
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum 7.13%