Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 844,611us-gaap_NetIncomeLoss	$ 733,993us-gaap_NetIncomeLoss	$ 623,925us-gaap_NetIncomeLoss
Other comprehensive (loss) income, net of tax
Foreign currency translation adjustment	(36,808)	(18,009)	1,400
Derivative financial instruments	20,722	2,157	(10,144)
Marketable securities	(424)	(953)	350
Pension and postretirement benefit plans	(165,757)	291,807	(122,551)
Total other comprehensive (loss) income, net of tax	(182,267)	275,002	(130,945)
Comprehensive income	$ 662,344us-gaap_ComprehensiveIncomeNetOfTax	$ 1,008,995us-gaap_ComprehensiveIncomeNetOfTax	$ 492,980us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans, attributable to parent entity.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss), attributable to parent entity.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

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