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Employee Benefits - U.S. and Canadian Other Post-Retirement Benefits Narrative (Details) - Other Post-Retirement Benefits - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Unrecognized prior-service cost | $ 1.0 | $ 1.0
Unrecognized loss | 13.0 | $ 3.0
Amounts in Accumulated other comprehensive income (loss) expected to be recognized as components of net periodic benefit cost in next fiscal year | 0.2 |
Expected employer contributions during next fiscal year | 5.0 |
Expected future benefit payments 2021 | 5.0 |
Expected future benefit payments 2026 – 2030 | $ 26.0 |
Maximum percentage of liability for future plan cost increases for pre-65 and medical supplement plan coverage | 5.00% |
Maximum percentage of medical supplement plan into future periods | 5.00% |
Maximum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Maximum percentage of liability for future plan cost increases for pre-65 and medical supplement plan coverage | 7.00% |
Minimum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Maximum percentage of liability for future plan cost increases for pre-65 and medical supplement plan coverage | 4.00% |

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