Retirement Benefits and Trusteed Assets (Assumptions Used in Determining the Accumulated Postretirement Benefit Obligation and Net Other Postretirement Benefit Costs) (Details) - Other postretirement benefit plan	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Accumulated postretirement benefit obligation
Discount rate	5.43%	5.66%	5.00%
Health care trend rate pre- 65	8.25%	8.50%	7.75%
Health care trend post- 65	8.75%	9.00%	8.25%
Ultimate health care trend rate	4.50%	4.50%	4.50%
Other postretirement benefit costs
Discount rate	5.66%	5.00%	5.19%
Expected long-term rate of return on plan assets	7.50%	7.60%	7.20%
Health care trend rate pre- 65	8.50%	7.75%	6.75%
Health care trend post- 65	9.00%	8.25%	7.25%
Ultimate health care trend rate	4.50%	4.50%	4.50%