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Retirement Benefits - Narrative (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2022 | Dec. 31, 2021 USD ($) employee | Dec. 31, 2020 USD ($) employee | Dec. 31, 2019 USD ($) | Dec. 31, 2018 | Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Defined contribution plan, deferred contributions due to COVID-19 pandemic |  |  |  |  | $ 7.3 |  |  |
Projected Retirement Benefit Expense In Next 12 months |  |  | $ 37.0 |  |  |  |  |
Defined Contribution Plan, Cost |  |  | $ 20.4 |  | 29.9 | $ 44.8 |  |
Termination benefits |  |  |  |  | 17.4 |  |  |
Multiemployer Plans, Withdrawal Obligation, Payment Period |  |  | 20 years |  |  |  |  |
Income tax provision (benefit) |  |  | $ 26.8 |  | 77.7 | (28.5) |  |
Settlement gain |  |  | (21.9) |  | 0.0 | 0.0 |  |
Reclassification out of Accumulated Other Comprehensive Income [Member] | Post- retirement benefit plans [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Income tax provision (benefit) | [1] |  | (11.9) |  | (19.7) | (20.3) |  |
Settlement gain |  |  | 21.9 | [2] | $ 0.0 | $ 0.0 |  |
Collective-Bargaining Arrangement, Other |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Income tax provision (benefit) |  |  | 15.5 |  |  |  |  |
Foreign Plan |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Plan assets pledged as collateral |  |  | $ 62.0 |  |  |  |  |
Other Postretirement Benefits |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Discount rate |  |  | 2.45% |  | 3.25% | 4.35% |  |
Curtailment loss (gain) |  |  | $ 0.0 |  | $ (0.2) | $ 0.0 |  |
Employer contributions |  |  | 0.0 |  | 0.0 |  |  |
Projected Retirement Benefit Expense In Next 12 months |  |  | 21.0 |  |  |  |  |
Defined Contribution Plan, Cost |  |  | $ 0.0 |  | $ 0.7 | $ 1.0 |  |
Assumed increase in per capita cost of covered benefits in next 12 months |  |  | 6.50% |  |  |  |  |
Assumed ultimate health care cost trend rate |  |  | 4.00% |  |  |  |  |
Expected long-term rate of return on assets |  |  | 0.00% |  | 0.00% | 4.00% |  |
Fair value of plan assets |  |  | $ 0.0 |  | $ 0.0 | $ 0.1 |  |
Termination benefits |  |  | 0.0 |  | 6.7 | $ 0.0 |  |
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement |  |  | 43.0 |  | 0.0 |  |  |
Settlement gain |  |  | $ 21.9 |  | $ 0.0 |  |  |
Pension Benefits [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Discount rate |  |  | 2.60% |  | 3.40% | 4.40% |  |
Curtailment loss (gain) |  |  | $ 0.0 |  | $ 0.0 | $ 0.0 |  |
Employer contributions |  |  | 77.3 |  | 138.8 |  |  |
Projected Retirement Benefit Expense In Next 12 months |  |  | 16.0 |  |  |  |  |
Accumulated benefit obligation |  |  | $ 2,498.0 |  | $ 2,703.9 |  |  |
Expected long-term rate of return on assets |  |  | 6.71% |  | 7.16% | 7.52% |  |
Actual return on plan assets |  |  | 12.40% |  | 15.20% | 15.10% | (4.80%) | 16.90%
Fair value of plan assets |  |  | $ 2,120.9 |  | $ 2,046.4 | $ 1,902.1 |  |
Defined Benefit Plan, Weighted Average Life Expectancy |  |  | 17 years |  |  |  |  |
Termination benefits |  |  | $ 0.0 |  | 10.9 | 0.0 |  |
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement |  |  | 0.0 |  | 0.0 |  |  |
Settlement gain |  |  | 0.0 |  | 0.0 |  |  |
Pension Benefits [Member] | Global debt securities and cash [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Unfunded commitments |  |  | 62.0 |  |  |  |  |
Pension Benefits [Member] | Private equity [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Unfunded commitments |  |  | 97.0 |  |  |  |  |
Fair value of plan assets |  |  | 176.7 |  | 130.0 |  |  |
Pension Benefits [Member] | Hedge funds [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Fair value of plan assets |  |  | 292.1 |  | 325.0 |  |  |
Pension Benefits [Member] | Real estate and other [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Unfunded commitments |  |  | 44.0 |  |  |  |  |
Fair value of plan assets |  |  | 25.8 |  | 26.9 |  |  |
Pension Benefits [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Fair value of plan assets |  |  | 0.0 |  | 0.0 |  |  |
Pension Benefits [Member] | Fair Value, Inputs, Level 3 [Member] | Private equity [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Fair value of plan assets |  |  | 0.0 |  | 0.0 |  |  |
Pension Benefits [Member] | Fair Value, Inputs, Level 3 [Member] | Hedge funds [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Fair value of plan assets |  |  | 0.0 |  | 0.0 |  |  |
Pension Benefits [Member] | Fair Value, Inputs, Level 3 [Member] | Real estate and other [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Fair value of plan assets |  |  | 0.0 |  | $ 0.0 |  |  |
Pension Benefits [Member] | Forecast |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Expected long-term rate of return on assets |  | 6.43% |  |  |  |  |  |
Pension Benefits [Member] | MultiemployerPlan1 [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Percent of Current Year Contributions to Plan that Company Contributions Exceed |  |  |  |  | 5.00% |  |  |
Multiemployer Plans, Withdrawal Obligation |  |  | 35.0 |  |  |  |  |
Pension Benefits [Member] | Nonqualified and U.K. [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Estimated employer contributions in next 12 months |  |  | $ 10.0 |  |  |  |  |
Pension Benefits [Member] | United States |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Defined benefit plan, number of employees accruing benefit service | employee |  |  | 1,100 |  |  |  |  |
Defined Benefit Plan, Percent Of Employees accruing benefit service |  |  | 10.00% |  |  |  |  |
Percent reduction in defined benefit plan participation |  |  | 60.00% |  |  |  |  |
Employer contributions |  |  | $ 67.0 |  | $ 130.0 | $ 145.0 |  |
Voluntary employer contributions to pension plan |  |  | 50.0 |  |  |  |  |
Expected future voluntary contributions to pension plan |  |  | 50.0 |  |  |  |  |
Estimated employer contributions in next 12 months |  |  | $ 0.0 |  |  |  |  |
Percentage of total assets |  |  | 90.00% |  |  |  |  |
Small annuity buy out [Member] | Pension Benefits [Member] |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Benefits paid |  |  | $ 70.0 |  | $ 86.0 |  |  |
Small annuity buy out [Member] | Pension Benefits [Member] | United States |  |  |  |  |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |  |  |  |  |
Number of participants | employee |  |  | 1,000 |  | 1,200 |  |  |
Percent of U.S. employees as participants |  |  | 7.00% |  | 8.00% |  |  |
[1] | These amounts exclude the impact of any deferred tax asset valuation allowances, when applicable, including recognition of stranded balances (see Note 17 for further explanation).
[2] | Amounts are included in nonoperating retirement benefit expense (see Note 14).

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