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Pension and Post-Employment Benefits - Movements in PBO and Fair Value of Plan Assets (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Change in PBO: |  |  |
Actuarial losses/(gains) | $ 69.9 | $ (28.2) | $ 7.7
Fair value of plan assets: |  |  |
Opening balance | 159.8 |  |
Settlements | 0.0 | (10.6) |
Closing balance | 48.1 | 159.8 |
United Kingdom Plan [Member] |  |  |
Change in PBO: |  |  |
Benefits paid | (45.6) | (37.3) |
Fair value of plan assets: |  |  |
Opening balance | 838.9 | 876.7 |
Benefits paid | (45.6) | (37.3) |
Actual return on assets | (258.7) | 17.5 |
Exchange effect | (82.5) | (7.4) |
Closing balance | 452.1 | 838.9 | 876.7
German Plan [Member] |  |  |
Change in PBO: |  |  |
Opening balance | 13.2 | 15.2 |
Interest cost | 0.1 | 0.1 | 0.1
Service cost | 0.1 | 0.1 | 0.1
Benefits paid | (0.3) | (0.4) |
Actuarial losses/(gains) | (4.0) | (0.7) |
Exchange effect | (0.9) | (1.1) |
Closing balance | 8.2 | 13.2 | 15.2
Fair value of plan assets: |  |  |
Benefits paid | (0.3) | (0.4) |
Pension Benefit Obligation [Member] |  |  |
Change in PBO: |  |  |
Settlements | (10.6) |  |
Pension Benefit Obligation [Member] | United Kingdom Plan [Member] |  |  |
Change in PBO: |  |  |
Opening balance | 679.1 | 758.7 |
Interest cost | 10.1 | 7.6 |
Service cost | 2.2 | 1.6 |
Benefits paid | (45.6) | (37.3) |
Settlements | 0.0 | (10.6) |
Plan amendments | 0.4 | 5.4 |
Actuarial losses/(gains) | (174.2) | (40.5) |
Exchange effect | (68.0) | (5.8) |
Closing balance | 404.0 | 679.1 | $ 758.7
Fair value of plan assets: |  |  |
Benefits paid | $ (45.6) | $ (37.3) |

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- Definition Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 + Details
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- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(4) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI https://asc.fasb.org/extlink&oid=123453770&loc=d3e1703-114919 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(10)) -URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3 -URI https://asc.fasb.org/extlink&oid=123453770&loc=d3e1731-114919 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 + Details
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- Definition Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(6) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Section 50 -Paragraph 4 -URI https://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964 + Details
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- Definition Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(5) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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