XML 50 R27.htm IDEA: XBRL DOCUMENT v2.4.0.6
Long-Term Debt (Details) (USD $)
 3 Months Ended
Mar. 31, 2013
Apr. 25, 2013
Apr. 12, 2013
Dec. 31, 2012
Debt Instrument [Line Items]        
Line of Credit Facility, Maximum Borrowing Capacity     $ 2,500,000,000  
Long-term credit facility 430,000,000 470,000,000   340,000,000
Letters of Credit Outstanding, Amount 800,000 [1] 800,000 [1]   800,000 [1]
Line of Credit Facility, Remaining Borrowing Capacity 569,200,000 829,200,000   659,200,000
Line of Credit Facility, Current Borrowing Capacity     1,300,000,000  
Borrowing Base, Line of Credit     1,900,000,000  
Deferred Finance Costs, Gross     3,300,000  
Line of Credit, Covenant Compliance, Maximum Annual Dividend Payment $ 50,000,000      
[1] (1) Letters of credit reduce the amount available under the credit facility on a dollar-for-dollar basis.