Retirement Benefits Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Qualified Pension Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	$ 4,632		$ 26,351
Defined Benefit Plan, Interest Cost	7,929		24,263
Qualified Pension Benefits [Member] | Parent Company [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	4,632	$ 6,797
Defined Benefit Plan, Interest Cost	7,929	6,087
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(12,652)	(12,777)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	(862)	1,628
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	(953)	1,735
Qualified Pension Benefits [Member] | Subsidiaries [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	4,632	6,797
Defined Benefit Plan, Interest Cost	7,929	6,087
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(12,652)	(12,777)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	0	3,806
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	(91)	3,913
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	71		557
Defined Benefit Plan, Interest Cost	424		1,253
Supplemental Employee Retirement Plan [Member] | Parent Company [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	71	139
Defined Benefit Plan, Interest Cost	424	313
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	73	72
Defined Benefit Plan, Amortization of Gain (Loss)	0	618
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	568	1,142
Supplemental Employee Retirement Plan [Member] | Subsidiaries [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	71	139
Defined Benefit Plan, Interest Cost	424	313
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	73	72
Defined Benefit Plan, Amortization of Gain (Loss)	22	663
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	590	1,187
Other Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	47		217
Defined Benefit Plan, Interest Cost	115		$ 311
Other Benefit [Member] | Parent Company [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	47	55
Defined Benefit Plan, Interest Cost	115	81
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(79)	(99)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	7	6
Defined Benefit Plan, Amortization of Gain (Loss)	(51)	(4)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	39	39
Other Benefit [Member] | Subsidiaries [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	47	55
Defined Benefit Plan, Interest Cost	115	81
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(79)	(99)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	7	6
Defined Benefit Plan, Amortization of Gain (Loss)	(54)	(6)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	$ 36	$ 37