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Employee Benefit Plans and Other Postretirement Benefits - Summary of Changes in Pension Plans' Level 3 Assets (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2021 USD ($)
Level 3 fair value of pension plans' assets [Roll Forward] |
Plan assets at fair value at beginning of period | $ 1,200.0
Fair value of plan assets at plan year end | 1,300.0
Pension Plans |
Level 3 fair value of pension plans' assets [Roll Forward] |
Plan assets at fair value at beginning of period | 1,300.7
Fair value of plan assets at plan year end | 1,382.7
Significant unobservable input (Level 3) | Private Equity Securities | Pension Plans |
Level 3 fair value of pension plans' assets [Roll Forward] |
Plan assets at fair value at beginning of period | 2.0
Purchases | 0.4
Sales | (0.9)
Fair value of plan assets at plan year end | $ 1.5

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