Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 3,836,254	$ 3,753,354
Less-Accumulated depreciation and amortization	1,941,806	1,863,921
Property, Plant and Equipment, Net	1,894,448	1,889,433
Regulatory Assets	29,516	19,670
Regulatory Liabilities	416,949	388,591
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract]
Allowance for funds used during construction, debt	700	200	$ 300
Allowance for funds used during construction, equity	2,300	1,400	400
Interest Payments [Abstract]
Cash payments for interest, net of interest capitalized	26,100	26,100	$ 26,100
Other Regulatory Assets (Liabilities) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory Liabilities	30,600	26,700
Asset Retirement Obligation
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory Assets	109,000	102,100
Transmission facilities
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,490,141	3,412,811
Storage facilities
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	142,326	136,608
Construction in progress
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	44,702	44,885
Other
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 159,085	$ 159,050
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Minimum [Member] | Transmission facilities
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	2.80%
Minimum [Member] | Storage facilities
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	1.60%
Minimum [Member] | Other
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	0.00%
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	30 years
Maximum [Member] | Transmission facilities
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	6.97%
Maximum [Member] | Storage facilities
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	2.76%
Maximum [Member] | Other
Public Utility, Property, Plant and Equipment [Line Items]
Depreciaton rates	33.33%