Accumulated Other Comprehensive Loss 2 Parentheticals (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Comprehensive Income Loss [Abstract]
Change in fair value of interest rate hedges tax	$ (27,589)	$ (5,237)	$ (3,051)
Reclassification of unrealized loss (gain) on interest rate hedges tax	9,012	9,019	8,222
Change in fair value of commodity hedges tax	2,598	14,093	3,773
Reclassification of unrealized gain (loss) on commodity hedges into earnings tax	(8,536)	(6,787)	(16,231)
Actuarial gain (loss) relating to pension and other postretirement benefit plan amendments, tax	(24,240)	(4,472)	6,535
Prior service cost relating to pension and other postretirement benefit plan amendments, tax	0	0	(151)
Reclassification of net actuarial loss and prior service credit relating to pension and other postretirement benefits into earnings tax	2,234	2,205	2,814
Change in other comprehensive income (loss) from equity investments tax	$ 88	$ 88	$ (1,744)