Pension and Other Postretirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan, Actual Return on Plan Assets [Abstract]
Estimated future employer contributions in next fiscal year	$ 40,800
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	100.00%	100.00%
Target allocation range, maximum	100.00%	100.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Health care cost trend rate assumed for next fiscal year	8.00%	8.00%	7.00%
Ultimate health care cost trend rate	5.00%	5.00%	5.00%
Pension Benefits
Defined Benefit Plan, Actual Return on Plan Assets [Abstract]
Employer contributions	40,600	41,461
Participant contributions	0	0
Benefits paid	(37,417)	(27,195)
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	45,500
2014	43,200
2015	41,400
2016	41,200
2017	40,400
After 2017	223,100
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	389,490
Unrealized gains/(losses)	23,670	21,883	20,691
Balance, end of year	430,894	389,490
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	22,215	16,497	15,502
Interest cost	24,896	22,684	21,763
Expected return on plan assets	(23,670)	(21,883)	(20,691)
Net actuarial loss	21,116	14,104	11,325
Prior service cost (gain)	1,380	1,404	1,405
Net periodic benefit cost	45,937	32,806	29,304
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.75%	5.50%	5.75%
Expected return on plan assets	6.25%	6.25%	6.25%
Rate of compensation increase	4.50%	4.25%	4.00%
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan, Actual Return on Plan Assets [Abstract]
Employer contributions	5,843	5,138
Participant contributions	1,107	1,739
Benefits paid	(6,950)	(6,877)
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	6,800
2014	6,700
2015	6,900
2016	7,000
2017	7,100
After 2017	36,800
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	0
Unrealized gains/(losses)	0	0	0
Balance, end of year	0	0
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2,336	2,141	2,086
Interest cost	3,355	3,679	3,918
Expected return on plan assets	0	0	0
Net actuarial loss	1,719	1,971	2,045
Prior service cost (gain)	(2,181)	(2,181)	(2,181)
Net periodic benefit cost	5,229	5,610	5,868
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.25%	4.75%	5.00%
Expected return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	0.00%	0.00%	0.00%
Equity Securities US
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	7.00%	7.00%
Target allocation range, minimum	3.00%	3.00%
Target allocation range, maximum	15.00%	15.00%
Equity Securities International
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	8.00%	7.00%
Target allocation range, minimum	3.00%	3.00%
Target allocation range, maximum	15.00%	15.00%
Fixed Income Investments US
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	57.00%	58.00%
Target allocation range, minimum	35.00%	35.00%
Target allocation range, maximum	75.00%	75.00%
Fixed Income Investments International
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	12.00%	11.00%
Target allocation range, minimum	3.00%	3.00%
Target allocation range, maximum	10.00%	10.00%
Absolute Return
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	9.00%	9.00%
Target allocation range, minimum	5.00%	5.00%
Target allocation range, maximum	15.00%	15.00%
Real assets
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	5.00%	5.00%
Target allocation range, minimum	3.00%	3.00%
Target allocation range, maximum	10.00%	10.00%
Private equity
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	1.00%	1.00%
Target allocation range, minimum	0.00%	0.00%
Target allocation range, maximum	3.00%	3.00%
Short-term Investments
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Actual Allocation	1.00%	2.00%
Target allocation range, minimum	0.00%	0.00%
Target allocation range, maximum	3.00%	3.00%
Quoted Prices in Active Markets for Identical Inputs (Level 1)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	264,410	237,245
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	15,609	13,926
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	6,505	6,073
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	544	244
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	33,603	27,300
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	120,457	111,590
Quoted Prices in Active Markets for Identical Inputs (Level 1) | US government debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	37,979	37,479
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	17,988	17,743
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	31,725	22,890
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Commingled funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Absolute Return
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Real assets
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Quoted Prices in Active Markets for Identical Inputs (Level 1) | Short-term Investments
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	83,929	67,758
Significant Other Observable Inputs (Level 2) | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	8,871	7,751
Significant Other Observable Inputs (Level 2) | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | US government debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	68,017	60,007
Significant Other Observable Inputs (Level 2) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Commingled funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Absolute Return
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Real assets
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	7,041	0
Significant Other Observable Inputs (Level 2) | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Other Observable Inputs (Level 2) | Short-term Investments
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year		68,125
Realized gains/(losses)		(2,095)
Unrealized gains/(losses)		4,902
Purchases		76,609
Sales		(63,054)
Balance, end of year	82,555	84,487
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets		(4,902)
Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	84,487
Realized gains/(losses)	1,445
Unrealized gains/(losses)	3,570
Transfers	(7,041)
Purchases	102,621
Sales	(102,527)
Balance, end of year	82,555
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	(3,570)
Significant Unobservable Inputs (Level 3) | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | US government debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Fixed Income Investments International | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	18,314
Realized gains/(losses)	35
Unrealized gains/(losses)	1,841
Purchases	2,000
Sales	(127)
Balance, end of year	22,063
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	(1,841)
Significant Unobservable Inputs (Level 3) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	0	0
Significant Unobservable Inputs (Level 3) | Commingled funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	22,063	18,314
Significant Unobservable Inputs (Level 3) | Absolute Return
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year		31,838
Realized gains/(losses)		(2,507)
Unrealized gains/(losses)		2,828
Purchases		7,500
Sales		(2,921)
Balance, end of year	37,289	36,738
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets		(2,828)
Significant Unobservable Inputs (Level 3) | Absolute Return | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	36,738
Realized gains/(losses)	1,125
Unrealized gains/(losses)	756
Purchases	3,505
Sales	(4,835)
Balance, end of year	37,289
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	(756)
Significant Unobservable Inputs (Level 3) | Real assets
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year		10,130
Realized gains/(losses)		143
Unrealized gains/(losses)		369
Purchases		7,080
Sales		(271)
Balance, end of year	12,702	17,451
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets		(369)
Significant Unobservable Inputs (Level 3) | Real assets | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	17,451
Realized gains/(losses)	54
Unrealized gains/(losses)	1,320
Transfers	(7,041)
Purchases	1,239
Sales	(321)
Balance, end of year	12,702
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	(1,320)
Significant Unobservable Inputs (Level 3) | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year		4,006
Realized gains/(losses)		243
Unrealized gains/(losses)		406
Purchases		178
Sales		(530)
Balance, end of year	3,807	4,303
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets		(406)
Significant Unobservable Inputs (Level 3) | Private equity | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	4,303
Realized gains/(losses)	231
Unrealized gains/(losses)	(347)
Purchases	183
Sales	(563)
Balance, end of year	3,807
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	347
Significant Unobservable Inputs (Level 3) | Short-term Investments
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year		6,060
Realized gains/(losses)		0
Unrealized gains/(losses)		0
Purchases		60,851
Sales		(59,230)
Balance, end of year	6,694	7,681
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets		0
Significant Unobservable Inputs (Level 3) | Short-term Investments | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year	7,681
Realized gains/(losses)	0
Unrealized gains/(losses)	0
Purchases	95,694
Sales	(96,681)
Balance, end of year	6,694
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	430,894	389,490
Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	15,609	13,926
Estimate of Fair Value, Fair Value Disclosure [Member] | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	15,376	13,824
Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	544	244
Estimate of Fair Value, Fair Value Disclosure [Member] | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	33,603	27,300
Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	120,457	111,590
Estimate of Fair Value, Fair Value Disclosure [Member] | US government debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	37,979	37,479
Estimate of Fair Value, Fair Value Disclosure [Member] | Mutual funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	86,005	77,750
Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	31,725	22,890
Estimate of Fair Value, Fair Value Disclosure [Member] | Commingled funds
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	22,063	18,314
Estimate of Fair Value, Fair Value Disclosure [Member] | Absolute Return
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	37,289	36,738
Estimate of Fair Value, Fair Value Disclosure [Member] | Real assets
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	19,743	17,451
Estimate of Fair Value, Fair Value Disclosure [Member] | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	3,807	4,303
Estimate of Fair Value, Fair Value Disclosure [Member] | Short-term Investments
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, end of year	6,694	7,681
Segment, Geographical, Groups of Countries, Group One [Member] | Significant Unobservable Inputs (Level 3) | Corporate debt
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance, beginning of year		16,091
Realized gains/(losses)		26
Unrealized gains/(losses)		1,299
Purchases		1,000
Sales		(102)
Balance, end of year		18,314
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Expected return on plan assets		(1,299)
January 1, 2019
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Ultimate health care cost trend rate	5.00%