Long-Term Debt (Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Long-term debt, beginning balance	$ 8,129,546
Payments and Retirements	(229,626)
New Borrowings	10,801
Long-term debt, ending balance	7,910,721
Less: Debt (Discount)/Premium	2,639		2,037
Less: Current Portion	(262,527)		(257,916)
Principal Outstanding	7,650,833		7,873,667
Weighted average interest rate	7.91%	[1]
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	8,107,066
Payments and Retirements	(228,750)
Long-term debt, ending balance	7,878,316
Weighted average interest rate	7.93%	[1]
Other Secured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	13,550
Payments and Retirements	(669)
New Borrowings	10,801
Long-term debt, ending balance	23,682
Weighted average interest rate	3.62%	[1]
Rural Utilities Service Loan Contracts [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	8,930
Payments and Retirements	(207)
Long-term debt, ending balance	$ 8,723
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 June 30, 2014 represent a weighted average of multiple issuances.