Basis of Presentation Changes in Accumulated Other Comprehensive Income / (Loss) by component (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Other Comprehensive Income (Loss), Net of Tax	$ 203,795	$ 13,872	$ 169,197	$ 97,446
Accumulated Other Comprehensive Income (Loss), Net of Tax	(155,920)		(155,920)		(325,117)
Accumulated Other Comprehensive Income (Loss) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Other comprehensive income before reclassifications			156,353
Amounts reclassified from accumulated other comprehensive income			12,844
Other Comprehensive Income (Loss), Net of Tax			169,197
Accumulated Other Comprehensive Income (Loss), Net of Tax	(155,920)		(155,920)		(325,117)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Other comprehensive income before reclassifications			(20,032)
Amounts reclassified from accumulated other comprehensive income			3,754
Other Comprehensive Income (Loss), Net of Tax			(16,278)
Accumulated Other Comprehensive Income (Loss), Net of Tax	26,215		26,215		42,493
Accumulated Defined Benefit Plans Adjustment [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Other comprehensive income before reclassifications			176,385
Amounts reclassified from accumulated other comprehensive income			9,090
Other Comprehensive Income (Loss), Net of Tax			185,475
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (182,135)		$ (182,135)		$ (367,610)