Pensions and Other Postretirement Plans (Obligation, Asset, and Funding Information) (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	$ 1,116,569,000	$ 1,286,694,000
Service cost	20,422,000	18,221,000	$ 18,687,000
Interest cost	46,821,000	46,787,000	47,925,000
Amendments	5,725,000	7,183,000
Actuarial (gain) loss	124,285,000	(81,851,000)
Benefits paid	(64,354,000)	(63,852,000)
Special termination benefits	6,432,000	0
Curtailment	0	(836,000)
Settlement	(235,544,000)	(95,777,000)
Benefit obligation at end of year	1,020,356,000	1,116,569,000	1,286,694,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	2,120,127,000	2,343,471,000
Actual return on plan assets	492,477,000	(63,715,000)
Employer contributions	0	0
Benefits paid	(64,354,000)	(63,852,000)
Settlement	(235,544,000)	(95,777,000)
Fair value of assets at end of year	2,312,706,000	2,120,127,000	2,343,471,000
Funded status	1,292,350,000	1,003,558,000
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	102,548,000	110,082,000
Service cost	858,000	819,000	858,000
Interest cost	4,314,000	3,865,000	4,233,000
Amendments	0	1,028,000
Actuarial (gain) loss	15,544,000	(7,552,000)
Benefits paid	(7,071,000)	(5,694,000)
Benefit obligation at end of year	116,193,000	102,548,000	110,082,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	0	0
Employer contributions	7,071,000	5,694,000
Benefits paid	(7,071,000)	(5,694,000)
Fair value of assets at end of year	0	0	0
Funded status	(116,193,000)	(102,548,000)
Other Postretirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at begining of year	8,523,000	22,785,000
Service cost	0	892,000	1,028,000
Interest cost	289,000	620,000	779,000
Amendments	0	(12,473,000)
Actuarial (gain) loss	(1,246,000)	(2,519,000)
Benefits paid, net of Medicare subsidy	(750,000)	(782,000)
Benefit obligation at end of year	6,816,000	8,523,000	22,785,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	0	0
Employer contributions	750,000	782,000
Benefits paid, net of Medicare subsidy	(750,000)	(782,000)
Fair value of assets at end of year	0	0	$ 0
Funded status	$ (6,816,000)	$ (8,523,000)