Accumulated Other Comprehensive Loss (Reclassifications) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Gains (losses) on cash flow hedges
Revenues		$ 869,541	$ 941,644	$ 2,641,113	$ 2,837,591
Interest expense, net		(20,165)	(22,158)	(65,200)	(67,704)
(Benefit) provision for income tax		42,676	25,310	145,574	79,681
Net income		93,876	136,882	335,445	285,008
Pension and Postretirement Benefit Plans
Benefit for income tax		(4,219)	(3,355)	(12,001)	(10,609)
Reclassification out of Accumulated Other Comprehensive Loss
Gains (losses) on cash flow hedges
Revenues	[1]	211	429	1,039	1,009
Cost of sales	[1]	(41)	(42)	544	(394)
Interest expense, net	[1]	(507)	(507)	(1,521)	(1,521)
Total before tax	[1]	(337)	(120)	62	(906)
(Benefit) provision for income tax	[1]	(132)	(47)	15	(350)
Net income	[1]	(205)	(73)	47	(556)
Gains (losses) on available for sale securities
Interest expense, net	[1]	1,085	(249)	1,043	(1,101)
Provision (benefit) for income tax	[1]	401	(92)	385	(406)
Net of tax	[1]	684	(157)	658	(695)
Pension and Postretirement Benefit Plans
Transition credit	[1],[2]	2	3	7	8
Prior service costs	[1],[2]	(60)	(27)	(179)	(81)
Actuarial losses	[1],[2]	(11,596)	(10,025)	(33,193)	(29,652)
Total before tax	[1],[2]	(11,654)	(10,049)	(33,365)	(29,725)
Benefit for income tax	[1],[2]	(4,219)	(3,355)	(12,001)	(10,609)
Net of tax	[1],[2]	$ (7,435)	$ (6,694)	$ (21,364)	$ (19,116)

[1] Amounts in parentheses indicate reductions to income and increases to other comprehensive income (loss).

[2] Reclassified from accumulated other comprehensive loss into selling, general and administrative expenses. These amounts are included in the computation of net periodic costs (see Note 12 for additional details).