Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 530,100	$ 328,000	$ 509,600
Other comprehensive income (loss)
Change in derivative instruments designated as cash flow hedges, net of tax	700	(1,400)	900
Foreign currency translation adjustment	(8,500)	12,100	(38,400)
Benefit plan adjustments, net of tax	(6,800)	(21,100)	6,000
Other comprehensive income (loss)	(14,600)	(10,400)	(31,500)
Comprehensive income	515,500	317,600	478,100
Comprehensive income attributable to noncontrolling interest			400
Comprehensive income attributable to common shareholders	$ 515,500	$ 317,600	$ 477,700