Retirement, Other Postretirement Benefits, And Defined Contribution Plans Investments Held For Qualified Pension And Other Postretirement Plans Measured At Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Fair Value Of Plan Assets Cash	$ 1,488	$ 10,601
Defined Benefit Plan Fair Value Of Plan Assets Other Pending Transactions	(22,404)	(13,813)
Defined Benefit Plan Fair Value Of Plan Assets Other Postretirement Assets Included In Total Investments	(64,391)	(61,285)
Defined Benefit Plan, Plan Assets, Amount	5,460,601	5,242,098
Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	10,827	12,178
Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	715,452	807,437
Qualified Pension Plans [Member] | Defined Benefit Plan, Common Collective Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	2,066,247	2,516,688
Qualified Pension Plans [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1,085,231	673,348
Qualified Pension Plans [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	924,904	525,184
Qualified Pension Plans [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	657,691	750,454
Qualified Pension Plans [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	79,657	15,395
Qualified Pension Plans [Member] | Other Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	5,899	5,911
Qualified Pension Plans [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	5,545,908	5,306,595
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Fair Value Of Plan Assets Other Pending Transactions	2,868	486
Defined Benefit Plan Fair Value Of Plan Assets Other Postretirement Assets Included In Qualified Pension Investments	64,391	61,285
Defined Benefit Plan, Plan Assets, Amount	673,141	623,824	$ 771,319
Other Postretirement Benefits Plan [Member] | Defined Benefit Plan, Common Collective Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	276,560	241,676
Other Postretirement Benefits Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	164,740	147,939
Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	106,523	113,273
Other Postretirement Benefits Plan [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	548	3,016
Other Postretirement Benefits Plan [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	57,511	56,149
Other Postretirement Benefits Plan [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	605,882	562,053
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	10,827	12,178
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	715,452	807,437
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	34,364	221,582
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	774	0
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Other Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	761,417	1,041,197
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefits Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	80,219	69,503
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefits Plan [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	548	3,016
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefits Plan [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefits Plan [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	80,767	72,519
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1,085,231	673,348
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	924,904	525,184
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	2,718	2,595
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	78,883	15,395
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Other Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	5,899	5,911
Fair Value, Inputs, Level 2 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	2,097,635	1,222,433
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefits Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	84,521	78,436
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	106,523	113,273
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefits Plan [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefits Plan [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	57,511	56,149
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefits Plan [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	248,555	247,858
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Other Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Qualified Pension Plans [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefits Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefits Plan [Member] | Registered Investment Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefits Plan [Member] | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefits Plan [Member] | Defined Benefit Plan Total Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	$ 0	$ 0