Pension and Postretirement Plans (Obligation, Asset, and Funding Information) (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	$ 1,317,480,000	$ 1,126,344,000
Service cost	26,294,000	27,792,000	$ 46,115,000
Interest cost	52,613,000	51,825,000	55,821,000
Amendments	4,606,000	8,374,000
Actuarial (gain) loss	(57,834,000)	172,548,000
Benefits paid	(85,542,000)	(69,854,000)
Curtailment	(3,319,000)	0
Settlement	0	451,000
Benefit obligation at end of year	1,254,298,000	1,317,480,000	1,126,344,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	2,469,968,000	2,371,849,000
Actual return on plan assets	(150,158,000)	167,154,000
Employer contributions and other	0	0	0
Benefits paid	(85,542,000)	(69,854,000)
Settlement	0	819,000
Fair value of assets at end of year	2,234,268,000	2,469,968,000	2,371,849,000
Funded status	979,970,000	1,152,488,000
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	116,083,000	91,169,000
Service cost	1,946,000	1,493,000	1,612,000
Interest cost	4,550,000	4,397,000	4,148,000
Amendments	0	4,022,000
Actuarial (gain) loss	(6,544,000)	19,168,000
Benefits paid	(6,083,000)	(4,166,000)
Curtailment	(4,948,000)	0
Benefit obligation at end of year	105,004,000	116,083,000	91,169,000
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	6,083,000	4,166,000
Benefits paid	(6,083,000)	(4,166,000)
Fair value of assets at end of year	0	0	0
Funded status	(105,004,000)	(116,083,000)
Other Postretirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	41,957,000	40,014,000
Service cost	1,331,000	1,500,000	2,488,000
Interest cost	1,299,000	1,448,000	1,848,000
Actuarial (gain) loss	(5,296,000)	4,448,000
Curtailment	0	(932,000)
Benefits paid, net of Medicare subsidy	(1,900,000)	(4,521,000)
Benefit obligation at end of year	37,391,000	41,957,000	40,014,000
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	1,900,000	4,521,000
Benefits paid, net of Medicare subsidy	(1,900,000)	(4,521,000)
Fair value of assets at end of year	0	0	$ 0
Funded status	$ (37,391,000)	$ (41,957,000)