Accumulated Other Comprehensive Income (Loss) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Other income (loss), net									$ 646	$ (1,418)	$ (13,081)
Loss from continuing operations before income tax benefit									(568,520)	(400,841)	(1,164,759)
Income tax benefit									97,952	41,838	99,204
Loss from continuing operations	(128,097)	(98,902)	(151,391)	(92,178)	(174,343)	(100,724)	(34,492)	(49,444)	(470,568)	(359,003)	(1,065,555)
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Income tax benefit									(230)
Loss from continuing operations									376
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Interest rate swaps
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Interest expense, net									(1,095)
Other income (loss), net									1,701
Loss from continuing operations before income tax benefit									606
Amortization of pension and other postretirement benefit plans | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Prior service cost									1,473
Net actuarial loss									17,862
Settlement loss									1,663
Loss from continuing operations before income tax benefit									20,998
Income tax benefit									0
Loss from continuing operations									$ 20,998