Components of Net Pension (Income) Expense (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
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| Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||
| Service cost | $ 23.2 | $ 27.6 | $ 47.4 | $ 55.4 |
| Interest on projected benefit obligation | 36.1 | 33.4 | 71.9 | 67.0 |
| Expected return on assets | (63.1) | (60.5) | (125.4) | (121.1) |
| Amortization of prior service costs | 0.4 | 0.4 | 0.7 | 0.7 |
| Recognized actuarial loss | 0.1 | 1.6 | 0.8 | 2.8 |
| Net pension (income) expense | $ (3.3) | $ 2.5 | $ (4.6) | $ 4.8 |
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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