Benefit Plans and Other Postretirement Benefits (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure
Plan contributions by employer	$ 22,800	$ 17,300
Expected benefits payments
Contributions to U.S defined contribution plans by the Company, maximum percentage of eligible compensation (as a percent)	5.00%
Matching contributions to U.S defined contribution plans by the Company	2,500	2,200
Pension Benefits
Defined Benefit Plan Disclosure
Unrecognized net loss in accumulated other comprehensive income	219,022
Net prior service cost in accumulated other comprehensive income	11,874
Net transition asset (obligation) in accumulated other comprehensive income	543
Net loss that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	17,552
Prior service cost that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	2,167
Net transition asset (obligation) that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	109
Plan contributions by employer	22,844	17,267
Estimated future employer contribution in next fiscal year	26,000
Expected benefits payments
2012	21,668
2013	22,435
2014	23,424
2015	24,569
2016	25,738
2017-2021	144,261
U.S. plans, Other Benefits
Defined Benefit Plan Disclosure
Unrecognized net loss in accumulated other comprehensive income	(9,747)
Net transition asset (obligation) in accumulated other comprehensive income	62
Net loss that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	(974)
Net transition asset (obligation) that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year	62
Expected benefits payments
Benefit payments per year, including amounts to be paid out of Company assets and reflecting future expected services, for the next ten years	$ 1,300