Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	$ 2,490,698	$ 3,140,775	$ 3,300,288
Other Comprehensive Loss, Net of Tax	(78,194)	(138,800)	(246,014)
As of	2,452,941	2,490,698	3,140,775
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	314,680	453,480
Other comprehensive (loss) income before reclassifications	(69,484)	(138,629)
Net amount reclassified from accumulated other comprehensive income	(8,710)	(171)
Other Comprehensive Loss, Net of Tax	(78,194)	(138,800)
As of	236,486	314,680	453,480
Foreign Currency Translation Adjustments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	(4,849)	8,548
Other comprehensive (loss) income before reclassifications	(22,149)	(18,898)	(16,061)
Net amount reclassified from accumulated other comprehensive income	0	5,501	(404)
Other Comprehensive Loss, Net of Tax	(22,149)	(13,397)	(16,465)
As of	(26,998)	(4,849)	8,548
Unrealized Gains (Losses) on Available- for- Sale Securities [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	58,500	52,130
Other comprehensive (loss) income before reclassifications	33,304	6,372	37,631
Net amount reclassified from accumulated other comprehensive income	1,127	(2)	(159,164)
Other Comprehensive Loss, Net of Tax	34,431	6,370	(121,533)
As of	92,931	58,500	52,130
Unrealized Gain (Loss) on Pensions and Other Postretirement Plans [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	261,029	392,910
Other comprehensive (loss) income before reclassifications	(80,349)	(126,132)
Net amount reclassified from accumulated other comprehensive income	(9,850)	(5,749)	(17,891)
Other Comprehensive Loss, Net of Tax	(90,199)	(131,881)	(108,536)
As of	170,830	261,029	392,910
Cash Flow Hedge [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	0	(108)
Other comprehensive (loss) income before reclassifications	(290)	29
Net amount reclassified from accumulated other comprehensive income	13	79
Other Comprehensive Loss, Net of Tax	(277)	108	520
As of	$ (277)	$ 0	$ (108)