Pension and Postretirement Plans - Narrative (Details)	3 Months Ended
	Mar. 31, 2025 USD ($) Plan	Mar. 31, 2024 USD ($)
Cincinnati Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Number of noncontributory defined benefit pension plans | Plan	3
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Pension curtailment gain	$ 0	$ 0
Pension settlement gain	1,000,000	0
Pension Plans, Defined Benefit [Member] | Hawaii Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Settlement	8,000,000
Decrease in benefit obligations	8,000,000
Pension settlement gain	1,000,000
Pension Plans, Defined Benefit [Member] | Cincinnati Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Settlement	700,000
Decrease in benefit obligations	700,000
Pension Plans, Defined Benefit [Member] | Qualified Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Contributions to pension plans	400,000	0
Expected future employer contributions, next fiscal year	2,000,000
Pension Plans, Defined Benefit [Member] | Nonqualified Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Contributions to pension plans	800,000	400,000
Expected future employer contributions, next fiscal year	2,000,000
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Expected future employer contributions, next fiscal year	7,000,000
Contributions to postretirement plans	1,400,000	1,600,000
Pension curtailment gain	200,000	0
Pension settlement gain	$ 0	$ 0