Retirement Benefits and Trusteed Assets (Pension Plan - Assumptions used in Determining the PBO and Net Pension Costs) (Details) - Pension plan	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Projected benefit obligation
Discount rate	5.65%	5.00%	5.19%
Rate of compensation increase	3.55%	3.80%	3.80%
Cash balance interest crediting rate	4.50%	3.60%	3.40%
Net pension costs
Discount rate	5.00%	5.19%	2.91%
Rate of compensation increase	3.80%	3.80%	3.80%
Expected long-term rate of return on plan assets	8.00%	7.60%	6.80%
Cash balance interest crediting rate	3.60%	3.40%	2.40%