Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Components of Deferred Tax Assets and Liabilities [Abstract]
Net operating loss carryforwards	$ 453,900,000	$ 445,800,000
Pension and postretirement benefits	155,000,000	134,600,000
Other	70,800,000	67,300,000
Total deferred tax assets	679,700,000	647,700,000
Valuation allowance	(58,400,000)	(60,000,000)
Net deferred tax assets, net of valuation allowance	621,300,000	587,700,000
Property, plant and equipment	159,800,000	127,900,000
Federal deferred liability on state deferred tax assets	7,800,000	8,000,000
Total deferred tax liabilities	167,600,000	135,900,000
Net deferred tax assets	453,700,000	451,800,000
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Operating Loss Carryforwards	1,100,000,000
Operating Loss Carryforwards, Valuation Allowance	394,300,000
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	14,400,000
Deferred Tax Assets, Tax Credit Carryforwards	12,000,000
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	59,600,000
Operating Loss Carryforwards, Expiration Dates	between 2021 and 2023
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	21,500,000	20,300,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
U.S. federal statutory rate	35.00%	35.00%	35.00%
State and local income taxes, net of federal income tax	2.90%	2.60%	1.30%
Change in valuation allowance, net of federal income tax	(4.40%)	(7.10%)	(2.40%)
State net operating loss adjustments	2.70%	0.10%	2.30%
Nondeductible interest expense	15.00%	13.30%	3.80%
Medicare drug subsidy law change	0.00%	5.80%	0.00%
Unrecognized tax benefit changes	2.80%	5.70%	0.80%
Nondeductible compensation	2.10%	1.50%	0.10%
Other differences, net	1.20%	1.00%	1.00%
Effective tax rate	57.30%	57.90%	41.90%
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal, current	0	300,000	2,500,000
State and local, current	400,000	700,000	1,500,000
Total current	400,000	1,000,000	4,000,000
Investment tax credits	(300,000)	(300,000)	(300,000)
Federal, deferred	24,300,000	44,000,000	59,800,000
State and local, deferred	3,500,000	1,400,000	6,900,000
Total deferred	27,800,000	45,400,000	66,700,000
Valuation allowance	(2,900,000)	(7,200,000)	(5,700,000)
Total	25,000,000	38,900,000	64,700,000
Income Tax Uncertainties [Abstract]
Balance, beginnging of year	20,500,000	16,700,000	15,600,000
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	1,300,000	4,000,000	1,100,000
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions	0	(200,000)	0
Balance, end of year	$ 21,800,000	$ 20,500,000	$ 16,700,000