Pension Benefits, Other Postretirement Benefits and Employee Savings and Investment Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0
Interest cost	5,641	6,758	7,356
Expected return of plan assets	(6,932)	(8,662)	(9,221)
Amortization of prior service credit	0	0	0
Amortization of net loss (gain)	1,514	1,828	1,755
Settlement charge	53,213	0	0
Net periodic benefit cost (credit)	53,436	(76)	(110)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	61	73	80
Interest cost	59	62	71
Expected return of plan assets	0	0	0
Amortization of prior service credit	(1,011)	(1,602)	(1,602)
Amortization of net loss (gain)	0	0	0
Settlement charge	0	0	0
Net periodic benefit cost (credit)	$ (891)	$ (1,467)	$ (1,451)