Retirement Benefit Plans (Assumptions Used in Accounting for Defined Benefit Plans) (Details) - Pension Plan	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets for net periodic benefit cost	7.00%	7.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Weighted average discount rates for pension benefit obligation	5.02%	5.36%
Weighted average discount rates for net periodic benefit cost	5.36%	2.53%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Weighted average discount rates for pension benefit obligation	5.04%	5.40%
Weighted average discount rates for net periodic benefit cost	5.40%	2.77%