Pension and Postretirement Plans (Obligation, Asset, and Funding Information) (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	$ 1,126,344,000	$ 1,466,322,000
Service cost	27,792,000	46,115,000	40,344,000
Interest cost	51,825,000	55,821,000	59,124,000
Amendments	8,374,000	22,700,000
Actuarial (gain) loss	172,548,000	(156,385,000)
Benefits paid	(69,854,000)	(81,162,000)
Curtailment	0	(55,690,000)
Settlement	451,000	(171,377,000)
Benefit obligation at end of year	1,317,480,000	1,126,344,000	1,466,322,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	2,371,849,000	2,071,145,000
Actual return on plan assets	167,154,000	699,518,000
Employer contributions and other	0	0	0
Benefits paid	(69,854,000)	(81,162,000)
Settlement	819,000	(317,652,000)
Fair value of assets at end of year	2,469,968,000	2,371,849,000	2,071,145,000
Funded status	1,152,488,000	1,245,505,000
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	91,169,000	104,062,000
Service cost	1,493,000	1,612,000	1,467,000
Interest cost	4,397,000	4,148,000	4,241,000
Amendments	4,022,000	0
Actuarial (gain) loss	19,168,000	(9,180,000)
Benefits paid	(4,166,000)	(4,101,000)
Curtailment	0	(2,059,000)
Settlement	0	(3,313,000)
Benefit obligation at end of year	116,083,000	91,169,000	104,062,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	0	0
Employer contributions and other	4,166,000	4,101,000
Benefits paid	(4,166,000)	(4,101,000)
Fair value of assets at end of year	0	0	0
Funded status	(116,083,000)	(91,169,000)
Other Postretirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	40,014,000	63,868,000
Service cost	1,500,000	2,488,000	3,113,000
Interest cost	1,448,000	1,848,000	2,735,000
Actuarial (gain) loss	4,448,000	(3,298,000)
Benefits paid, net of Medicare subsidy	(4,521,000)	(3,671,000)
Curtailment	(932,000)	(21,221,000)
Benefit obligation at end of year	41,957,000	40,014,000	63,868,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	0	0
Employer contributions and other	4,521,000	3,671,000
Benefits paid, net of Medicare subsidy	(4,521,000)	(3,671,000)
Fair value of assets at end of year	0	0	0
Funded status	$ (41,957,000)	$ (40,014,000)