Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Pension Plans, Defined Benefit [Member]	Dec. 31, 2013 Other Postretirement Benefit Plans, Defined Benefit [Member]	Dec. 31, 2012 Trend rate grading ratably to an assumption in 2082 [Member]	Dec. 31, 2012 Qualified Salaried Pension Plan [Member]	Dec. 31, 2011 Qualified Salaried Pension Plan [Member]	Dec. 31, 2012 Qualified Non-Represented Pension Plan [Member]	Dec. 31, 2011 Qualified Non-Represented Pension Plan [Member]	Dec. 31, 2012 Qualified Hourly Pension Plan [Member]	Dec. 31, 2012 Discretionary Funding [Member]	Dec. 31, 2011 Discretionary Funding [Member]
Defined Benefit Plan Disclosure [Line Items]
401(K) contributions by employer	$ 1,600,000	$ 1,400,000	$ 1,200,000
Accumulated benefit obligation	438,597,000	412,322,000
Estimated net loss to be amortized from Accumulated Other Comprehensive Loss ino Net Periodic Benefit Cost				19,800,000	3,300,000
Estimated prior service cost to be amortized from Accumulated Other Comprehensive Loss ino Net Periodic Benefit Cost				800,000	9,700,000
Health care cost trend rate assumed for next fiscal year	7.70%					5.00%
Contributions							9,300,000	5,000,000	5,500,000	4,400,000	6,800,000	11,900,000	5,800,000
Pension Contributions	21,630,000	9,400,000	0
Non-Qualified Pension Plan, Estimated Payments in Next Fiscal Year	$ 1,800,000