Pension and Other Postretirement Benefits Costs - Schedule of Amount Recognized in AOCL (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Qualified Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
AOCL, Prior Service Costs (Credit)	$ 0	$ 0
AOCL, Net Actuarial Loss	15,399	17,434
AOCL, Total	15,399	17,434
Pension Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory Assets, Prior Service Cost (Credit)	0	0
Regulatory Assets, Net Actuarial Loss	112,182	164,446
Regulatory Assets	112,182	164,446
Postretirement Benefit Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory Assets, Prior Service Cost (Credit)	(333)	(801)
Regulatory Assets, Net Actuarial Loss	5,834	7,167
Regulatory Assets	$ 5,501	$ 6,366