Long-Term Debt (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended				12 Months Ended			1 Months Ended	3 Months Ended		12 Months Ended			12 Months Ended			12 Months Ended						12 Months Ended					3 Months Ended		1 Months Ended	12 Months Ended	0 Months Ended		12 Months Ended		0 Months Ended	12 Months Ended				12 Months Ended					12 Months Ended			12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended
	Oct. 02, 2012	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2013 property	Dec. 31, 2012	Dec. 31, 2011 property	Apr. 24, 2013 Senior Notes [Member]	Jun. 30, 2013 Senior Notes [Member]	Apr. 10, 2013 Senior Notes [Member]	Dec. 31, 2012 Senior Note Due 1/15/2013 [Member]	Dec. 31, 2013 Senior Note Due 5/1/2014 [Member]	May 17, 2012 Senior Note Due 5/1/2014 [Member]	Dec. 31, 2013 Senior Note Due 3/15/2015 [Member]	Apr. 24, 2013 Senior Note Due 3/15/2015 [Member]	Apr. 10, 2013 Senior Note Due 3/15/2015 [Member]	Dec. 31, 2013 Senior Note Due 4/15/2015 [Member]	Dec. 31, 2012 Senior Note Due 4/15/2015 [Member]	Apr. 24, 2013 Senior Note Due 4/15/2015 [Member]	Apr. 10, 2013 Senior Note Due 4/15/2015 [Member]	Oct. 02, 2012 Senior Note Due 4/15/2015 [Member]	May 17, 2012 Senior Note Due 4/15/2015 [Member]	Dec. 31, 2013 Senior Note Due 10/14/2016 [Member]	Dec. 31, 2013 Senior Note Due 4/15/2017 [Member]	Jun. 30, 2013 Senior Note Due 4/15/2017 [Member]	Apr. 24, 2013 Senior Note Due 4/15/2017 [Member]	Oct. 02, 2012 Senior Note Due 4/15/2017 [Member]	Jun. 30, 2013 Senior Note Due 10/1/2018 [Member]	Jun. 30, 2013 Senior Note Due 4/15/2020 [Member]	May 17, 2012 Senior Note Due 7/1/2021 [Member]	Dec. 31, 2013 Senior Note Due 7/1/2021 [Member]	Oct. 02, 2012 Senior Note Due 1/15/2023 [Member]	Aug. 15, 2012 Senior Note Due 1/15/2023 [Member]	Dec. 31, 2013 Senior Note Due 1/15/2023 [Member]	Dec. 31, 2012 Senior Note Due 1/15/2023 [Member]	Apr. 10, 2013 Senior Notes Due 2024 [Member]	Dec. 31, 2013 Senior Notes Due 2024 [Member]	Dec. 31, 2013 Senior Unsecured Debt [Member]	Dec. 31, 2011 Senior Unsecured Debt [Member]	Dec. 31, 2012 Senior Unsecured Debt [Member]	Dec. 31, 2013 Rural Utilities Service Loan Contracts [Member]	Dec. 31, 2011 Rural Utilities Service Loan Contracts [Member]	Dec. 31, 2012 Rural Utilities Service Loan Contracts [Member]	Dec. 31, 2012 CoBank Term Loan 2012 [Member]	Dec. 31, 2013 CoBank Term Loan 2013 [Member]	Dec. 31, 2013 Revolving Credit Facility [Member] item	Dec. 31, 2013 Revolving Credit Facility [Member] Base Rate [Member]	Dec. 31, 2013 Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 Unsecured Letter of Credit Facility [Member]	Dec. 31, 2012 Unsecured Letter of Credit Facility [Member] item	Dec. 31, 2011 Unsecured Letter of Credit Facility [Member]	Dec. 31, 2013 Unsecured Letter of Credit Facility [Member] Letter Of Credit, Extension [Member]	Dec. 31, 2012 Unsecured Letter of Credit Facility [Member] Letter Of Credit, Extension [Member]	Dec. 31, 2013 Letter Of Credit, March 2013 [Member]	Dec. 31, 2012 Letter Of Credit, March 2013 [Member]	Dec. 31, 2013 Letter Of Credit, September 2013 [Member]	Dec. 31, 2012 Letter Of Credit, September 2013 [Member]	Dec. 31, 2013 Minimum [Member] Senior Note Due 10/14/2016 [Member] Base Rate [Member]	Dec. 31, 2013 Minimum [Member] Senior Note Due 10/14/2016 [Member] London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 Minimum [Member] Revolving Credit Facility [Member] Base Rate [Member]	Dec. 31, 2013 Minimum [Member] Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 Maximum [Member] Senior Note Due 10/14/2016 [Member] Base Rate [Member]	Dec. 31, 2013 Maximum [Member] Senior Note Due 10/14/2016 [Member] London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 Maximum [Member] Revolving Credit Facility [Member] Base Rate [Member]	Dec. 31, 2013 Maximum [Member] Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 2013 Pension Real Estate Contributions [Member]	Dec. 31, 2013 2011 Pension Real Estate Contributions [Member]	Dec. 31, 2013 Pension Benefits [Member] property	Dec. 31, 2011 Pension Benefits [Member]
Debt Instrument [Line Items]
Debt instrument, face amount																								$ 575,000,000							$ 500,000,000		$ 250,000,000	$ 600,000,000			$ 750,000,000
Interest Rate														8.25%			6.625%				7.875%				8.25%				8.125%	8.50%	9.25%			7.125%			7.625%
Remaining outstanding principal			8,942,568,000			8,129,546,000	8,942,568,000																																8,107,066,000		8,919,696,000	8,930,000	200,000,000	9,322,000	143,000,000	130,000,000
Line of credit facility maximum borrowing capacity																																															750,000,000				40,000,000	190,000,000				20,000,000		20,000,000
Line of credit facility expiration date																																															Nov. 03, 2016			Sep. 30, 2011			Sep. 30, 2012		Mar. 31, 2013		Sep. 30, 2013
Debt Instrument, Issuance Date															Apr. 24, 2013			Oct. 01, 2012														May 17, 2012				Aug. 15, 2012		Apr. 10, 2013
Debt instrument, maturity date													May 01, 2014		Mar. 15, 2015			Apr. 15, 2015	Apr. 01, 2015					Oct. 14, 2016	Apr. 15, 2017				Oct. 01, 2018	Apr. 15, 2020		Jul. 01, 2021			Jan. 15, 2023			Apr. 15, 2024
Issue price expressed as a percentage of principal amount (in hundredths)																															100.00%		104.25%	100.00%			100.00%
Proceeds from debt, net of issuance costs																															489,600,000		255,900,000	588,100,000			736,900,000
Aggregate principal amount agreed to be purchased											471,300,000			400,000,000		700,000	194,200,000			800,000	277,100,000	75,700,000	49,500,000				225,000,000	59,300,000
Amount of consideration for purchase of notes	154,700,000										532,400,000			446,000,000		800,000	216,000,000			900,000	316,400,000		54,000,000				267,700,000
Payments and Retirements						(1,563,022,000)		552,400,000																															(1,562,630,000)	551,400,000		(392,000)	1,000,000
Losses on early extinguishment of debt	19,300,000	(159,800,000)	(19,300,000)	(200,000)	(70,800,000)	159,780,000	90,363,000		104,900,000	54,900,000									69,000,000
Loss on early extinguishment of debt, net of tax									64,900,000	34,000,000
Loss on early extinguishment of debt, net of tax (in dollars per share)									$ 0.06	$ 0.04
Loss on repurchase of debt												(2,100,000)
Repurchase of senior notes												78,100,000														208,800,000			17,300,000	78,500,000
Repayment of the outstanding principal balance, quarterly installments amount																								14,400,000
Interest Rate Margin																																																											0.875%	1.875%	0.50%	1.50%	2.875%	3.875%	1.50%	2.50%
Initial pricing for LIBOR based borrowings (in hundredths)																								2.875%																								1.00%	2.00%
Maximum permitted leverage ratio																																															4.5
Line of credit facility, current borrowings						46,845,000																																									0
Interest Rate (in thousandths)																																															0.40%
Exercised extension of commitment																																																						100,000,000
Number of letters of credit																																																			2
Number of properties contributed						4		4																																																													4
Contribution of Property						23,422,000		58,100,000																																																													23,400,000	58,100,000
Pension Building Contribution Aggregate Annual Rent																																																																			2,100,000	5,800,000
Pension Building Contribution Minimum Lease Payments Sale Leaseback Transactions						107,102,000
Lease term of contributed property						15 years		15 years																																																													15 years
Sale and leaseback term, minimum (in years)						12 years
Sale and leaseback term, maximum (in years)						23 years
Other Liabilities, Noncurrent			266,625,000			262,308,000	266,625,000																																																														23,300,000
Other Liabilities, Current			232,836,000			324,181,000	232,836,000																																																														100,000
Bridge loan facility						1,900,000,000
Commitments fees related to bridge loan facility						$ 1,300,000