Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Changes in Benefit Obligation, Plan Assets and Funded Status for Pension and OPEB Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Amounts recognized in the consolidated balance sheets [Abstract]
Noncurrent liabilities	$ (83,674)	$ (128,807)
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	(408,429)	(474,237)
Service cost	(8,182)	(8,932)	$ (7,767)
Interest cost	(10,533)	(12,263)	(18,465)
Actuarial gain (loss)	17,204	(38,366)
Benefits paid	23,735	23,614
Plan settlements		101,755
Benefit obligation at end of year	(386,205)	(408,429)	(474,237)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	325,790	398,468
Actual return on plan assets	22,597	46,672
Employer contributions and benefit payments	5,144	6,019
Benefits paid	(23,735)	(23,614)
Plan settlements		(101,755)
Fair value of plan assets at end of year	329,796	325,790	398,468
Amounts recognized in the consolidated balance sheets [Abstract]
Current liabilities	(2,462)	(2,363)
Noncurrent assets		1,907
Noncurrent liabilities	(53,947)	(82,183)
Funded status	(56,409)	(82,639)
OPEB [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	(50,835)	(46,395)
Service cost	(670)	(508)	(371)
Interest cost	(1,267)	(1,502)	(1,588)
Actuarial gain (loss)	16,614	(6,415)
Benefits paid	3,900	3,985
Benefit obligation at end of year	(32,258)	(50,835)	$ (46,395)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer contributions and benefit payments	3,900	3,985
Benefits paid	(3,900)	(3,985)
Amounts recognized in the consolidated balance sheets [Abstract]
Current liabilities	(2,531)	(4,211)
Noncurrent liabilities	(29,727)	(46,624)
Funded status	$ (32,258)	$ (50,835)