Long-Term Debt (Long-Term Debt) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2011	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term debt, beginning balance	$ 8,942,568,000
Payments and Retirements	(1,563,022,000)		552,400,000
New Borrowings	750,000,000
Long-term debt, ending balance	8,129,546,000
Less: Debt (Discount)/Premium	2,037,000			(71,000)
Less: Current Portion	(257,916,000)			(560,550,000)
Principal Outstanding	7,873,667,000			8,381,947,000
Weighted average interest rate	7.95%	[1]
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	8,919,696,000
Payments and Retirements	(1,562,630,000)		551,400,000
New Borrowings	750,000,000
Long-term debt, ending balance	8,107,066,000
Weighted average interest rate	7.95%	[1]
Industrial Development Revenue Bonds [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	13,550,000
Payments and Retirements
New Borrowings
Long-term debt, ending balance	13,550,000
Weighted average interest rate	6.33%	[1]
Rural Utilities Service Loan Contracts [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	9,322,000
Payments and Retirements	(392,000)		1,000,000
Long-term debt, ending balance	$ 8,930,000		$ 200,000,000
Weighted average interest rate	6.15%	[1]

[1] Interest rate includes amortization of debt issuance costs and debt premiums or discounts. The interest rates at December 31, 2013 represent a weighted average of multiple issuances.