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Pension and Post-Employment Benefits - Reconciliation of Fair Value of Plan Assets Measured Using Significant Unobservable Inputs (Detail) - United Kingdom Plan [Member] - Significant Unobservable Inputs (Level 3) [Member] - Other Assets [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning balance | $ 431.8 | $ 162.2
Realized/unrealized gains/(losses): |  |
Relating to assets still held at the reporting date | 16.9 | (206.6)
Purchases, issuances and settlements | (33.7) | 502.8
Exchange effect | 23.7 | (26.6)
Ending balance | $ 438.7 | $ 431.8

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