Retirement Plans (Amounts Recognized as a Component of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2014
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Settlement costs recognized during year	$ (4,000)	$ (40,000)	$ (44,163)
Pension Benefits [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Accumulated other comprehensive income at beginning of year			697,874	411,432
Net actuarial gain (loss) recognized during year			(36,930)	(19,951)
Prior service (cost) credit recognized during year			(8)	(45)
Net actuarial loss (gain) occurring during year			(205,341)	140,832
Settlement costs recognized during year			(44,163)
Net amount recognized in comprehensive income for the year			(286,442)	120,836
Accumulated other comprehensive income at end of year	411,432		411,432	532,268
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Accumulated other comprehensive income at beginning of year			74,264	5,230
Net actuarial gain (loss) recognized during year			(7,846)	(2,916)
Prior service (cost) credit recognized during year			6,101	3,911
Net actuarial loss (gain) occurring during year			(67,289)	112,525
Net amount recognized in comprehensive income for the year			(69,034)	113,520
Accumulated other comprehensive income at end of year	$ 5,230		$ 5,230	$ 118,750