Long-Term Debt (Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Long-term debt, beginning balance	$ 8,129,546
Payments and Retirements	(244,780)
New Borrowings	1,560,801
Long-term debt, ending balance	9,445,567
Less: Debt (Discount)/Premium	2,570		2,037
Less: Current Portion	(262,534)		(257,916)
Principal Outstanding	9,185,603		7,873,667
Weighted average interest rate	7.76%	[1]
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	8,107,066
Payments and Retirements	(243,125)
New Borrowings	1,550,000
Long-term debt, ending balance	9,413,941
Weighted average interest rate	7.77%	[1]
Other Secured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	13,550
Payments and Retirements	(1,344)
New Borrowings	10,801
Long-term debt, ending balance	23,007
Weighted average interest rate	3.71%	[1]
Rural Utilities Service Loan Contracts [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	8,930
Payments and Retirements	(311)
Long-term debt, ending balance	$ 8,619
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 September 30, 2014 represent a weighted average of multiple issuances.