Long-Term Debt (Details) (USD $)	3 Months Ended			3 Months Ended		3 Months Ended								3 Months Ended																																																																		3 Months Ended					3 Months Ended
	Mar. 31, 2012		Dec. 31, 2011	Mar. 31, 2012 Unsecured Letter of Credit Facility [Member]	Sep. 19, 2011 Unsecured Letter of Credit Facility [Member]	Mar. 31, 2012 Revolving Credit Facility [Member]	Mar. 31, 2012 Senior Notes and Debentures [Member]	Dec. 31, 2011 Senior Notes and Debentures [Member]		Mar. 31, 2012 Senior Note Due 10/14/2016 [Member]		Dec. 31, 2011 Senior Note Due 10/14/2016 [Member]		Mar. 31, 2012 Line of Credit CoBank [Member]	Mar. 31, 2012 Senior Note [Member]	Dec. 31, 2011 Senior Note [Member]	Mar. 31, 2012 Senior Note [Member] Senior Note Due 1/15/2013 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 1/15/2013 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 5/1/2014 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 5/1/2014 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 3/15/2015 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 3/15/2015 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 4/15/2015 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 4/15/2015 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 4/15/2017 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 4/15/2017 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 10/1/2018 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 10/1/2018 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 3/15/2019 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 3/15/2019 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 4/15/2020 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 4/15/2020 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 4/15/2022 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 4/15/2022 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 1/15/2027 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 1/15/2027 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 2/15/2028 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 2/15/2028 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 10/15/2029 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 10/15/2029 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 8/15/2031 [Member]	Dec. 31, 2011 Senior Note [Member] Senior Note Due 8/15/2031 [Member]		Mar. 31, 2012 Senior Note [Member] Senior Note Due 10/14/2016 [Member]		Dec. 31, 2011 Senior Note [Member] Senior Note Due 10/14/2016 [Member]		Mar. 31, 2012 Debentures [Member]	Dec. 31, 2011 Debentures [Member]	Mar. 31, 2012 Debentures [Member] Debenture Due 11/1/2025 [Member]	Dec. 31, 2011 Debentures [Member] Debenture Due 11/1/2025 [Member]		Mar. 31, 2012 Debentures [Member] Debenture Due 8/15/2026 [Member]	Dec. 31, 2011 Debentures [Member] Debenture Due 8/15/2026 [Member]		Mar. 31, 2012 Debentures [Member] Debenture Due 10/1/2034 [Member]	Dec. 31, 2011 Debentures [Member] Debenture Due 10/1/2034 [Member]		Mar. 31, 2012 Debentures [Member] Debenture Due 7/1/2035 [Member]	Dec. 31, 2011 Debentures [Member] Debenture Due 7/1/2035 [Member]		Mar. 31, 2012 Debentures [Member] Debenture Due 10/1/2046 [Member]	Dec. 31, 2011 Debentures [Member] Debenture Due 10/1/2046 [Member]		Mar. 31, 2012 Subsidiary Senior Notes Due 12/1/2012 [Member]	Dec. 31, 2011 Subsidiary Senior Notes Due 12/1/2012 [Member]		Mar. 31, 2012 Rural Utilities Service [Member]		Mar. 31, 2012 Senior Unsecured Debt [Member]		Dec. 31, 2011 Senior Unsecured Debt [Member] Senior Note [Member] Senior Note Due 10/14/2016 [Member]	Mar. 31, 2012 Industrial Development Revenue Bonds [Member]
Long Term Debt [Roll Forward]
Long-term debt, beginning balance	$ 8,349,521,000						$ 8,311,399,000	$ 8,325,774,000							$ 7,816,532,000	$ 7,830,907,000	$ 580,724,000	$ 580,724,000		$ 600,000,000	$ 600,000,000		$ 300,000,000	$ 300,000,000		$ 500,000,000	$ 500,000,000		$ 1,100,000,000	$ 1,100,000,000		$ 600,000,000	$ 600,000,000		$ 434,000,000	$ 434,000,000		$ 1,100,000,000	$ 1,100,000,000		$ 500,000,000	$ 500,000,000		$ 345,858,000	$ 345,858,000		$ 200,000,000	$ 200,000,000		$ 50,000,000	$ 50,000,000		$ 945,325,000	$ 945,325,000		$ 560,625,000	[1]	$ 575,000,000	[1]	$ 458,867,000	$ 458,867,000	$ 138,000,000	$ 138,000,000		$ 1,739,000	$ 1,739,000		$ 628,000	$ 628,000		$ 125,000,000	$ 125,000,000		$ 193,500,000	$ 193,500,000		$ 36,000,000	$ 36,000,000		$ 10,197,000		$ 8,325,774,000		$ 575,000,000	$ 13,550,000
Payments	(14,502,000)																																																																															(127,000)		(14,375,000)			0
Borrowings	0																																																																															0		0			0
Long-term debt, ending balance	8,335,019,000						8,311,399,000	8,325,774,000							7,816,532,000	7,830,907,000	580,724,000	580,724,000		600,000,000	600,000,000		300,000,000	300,000,000		500,000,000	500,000,000		1,100,000,000	1,100,000,000		600,000,000	600,000,000		434,000,000	434,000,000		1,100,000,000	1,100,000,000		500,000,000	500,000,000		345,858,000	345,858,000		200,000,000	200,000,000		50,000,000	50,000,000		945,325,000	945,325,000		560,625,000	[1]	575,000,000	[1]	458,867,000	458,867,000	138,000,000	138,000,000		1,739,000	1,739,000		628,000	628,000		125,000,000	125,000,000		193,500,000	193,500,000		36,000,000	36,000,000		10,070,000		8,311,399,000		575,000,000	13,550,000
Less: Debt Discount	(45,881,000)		(49,664,000)
Less: Current Portion	(674,746,000)		(94,016,000)
Principal Outstanding	7,614,392,000		8,205,841,000
Interest Rate (in hundredths)	7.92%	[2]																																																																														6.15%	[2]	7.92%	[2]		6.33%	[2]
Principal Outstanding	8,335,019,000						8,311,399,000	8,325,774,000							7,816,532,000	7,830,907,000	580,724,000	580,724,000		600,000,000	600,000,000		300,000,000	300,000,000		500,000,000	500,000,000		1,100,000,000	1,100,000,000		600,000,000	600,000,000		434,000,000	434,000,000		1,100,000,000	1,100,000,000		500,000,000	500,000,000		345,858,000	345,858,000		200,000,000	200,000,000		50,000,000	50,000,000		945,325,000	945,325,000		560,625,000	[1]	575,000,000	[1]	458,867,000	458,867,000	138,000,000	138,000,000		1,739,000	1,739,000		628,000	628,000		125,000,000	125,000,000		193,500,000	193,500,000		36,000,000	36,000,000		10,070,000		8,311,399,000		575,000,000	13,550,000
Interest Rate (in hundredths)							7.92%	7.93%	[2]	312.50%	[1]	317.50%	[1]	0.625%			6.25%	6.25%	[2]	8.25%	8.25%	[2]	6.625%	6.625%	[2]	7.875%	7.875%	[2]	8.25%	8.25%	[2]	8.125%	8.125%	[2]	7.125%	7.125%	[2]	8.50%	8.50%	[2]	8.75%	8.75%	[2]	7.875%	7.875%	[2]	6.73%	6.73%	[2]	8.40%	8.40%	[2]	9.00%	9.00%	[2]							7.00%	7.00%	[2]	6.80%	6.80%	[2]	7.68%	7.68%	[2]	7.45%	7.45%	[2]	7.05%	7.05%	[2]	8.05%	8.05%	[2]
Credit Agreement [Abstract]
Repayment of the outstanding principal balance, quarterly installments amount														14,375,000
First payment date of the quarterly repayment of the outstanding principal balance														2012-03-31
Interest rate margin for Base Rate borrowings, minimum (in hundredths)														0.875%
Interest rate margin for Base Rate borrowings, maximum (in hundredths)														2.875%
Interest rate margin for LIBOR borrowings, minimum (in hundredths)														1.875%
Interest rate margin for LIBOR borrowings, maximum (in hundredths)														3.875%
Initial pricing for LIBOR based borrowings (in hundredths)														2.875%
Maximum permitted leverage ratio														4.5
Credit facilities [Abstract]
Line of credit initiation date				2010-09-08		2010-03-23
Line of credit facility expiration date						2016-10-14
Line of credit facility maximum borrowing capacity				100,000,000	190,000,000	750,000,000
Exercised extension of commitment				100,000,000
Date that the Bank to exercise its option to extend the commitments	2012-09-20
Principal payments by year [Abstract]
Principal Payments 2012 (remaining nine months)	79,514,000
Principal Payments 2013	638,767,000
Principal Payments 2014	658,017,000
Principal Payments 2015	858,049,000
Principal Payments 2016	345,466,000
Principal Payments 2017	$ 1,100,501,000

[1] Represents borrowings under the Credit Agreement with CoBank, as discussed below.

[2] Interest rate includes amortization of debt issuance costs and debt premiums or discounts. The interest rates at March 31, 2012 represent a weighted average of multiple issuances.