Retirement Plans (Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9,940	$ 12,834
Interest cost on projected benefit obligation	19,824	18,880
Expected return on plan assets	(23,512)	(24,590)
Amortization of prior service cost/(credit)	11	2
Amortization of unrecognized loss	4,819	10,072
Net periodic benefit cost	11,082	17,198
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	2,553	3,179
Interest cost on projected benefit obligation	4,788	4,440
Expected return on plan assets	(7)	(43)
Amortization of prior service cost/(credit)	(890)	(1,525)
Amortization of unrecognized loss	722	2,228
Net periodic benefit cost	$ 7,166	$ 8,279