Represents the per unit value of the investment.

No definition available.

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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

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
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- Definition

Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

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Employee Benefit Plans - Defined Benefit Pension Plans (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / item	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Employee benefit plans
Fair value of plan assets	$ 478.1	$ 441.7
Fixed income common trust funds
Employee benefit plans
Fair value of plan assets	315.4	255.6
Commingled global fund allocation
Employee benefit plans
Fair value of plan assets	81.7	110.3
Global equity common trust funds
Employee benefit plans
Fair value of plan assets	32.1	30.1
U.S. Government securities
Employee benefit plans
Fair value of plan assets	25.2	24.5
Non-U.S. Government securities
Employee benefit plans
Fair value of plan assets	0.3	13.2
Short-term investments
Employee benefit plans
Fair value of plan assets	$ 22.5	7.1
Value of short-term investments (in dollars per unit) \| $ / item	1.00
Other
Employee benefit plans
Fair value of plan assets	$ 0.9	0.9
Quoted Prices in Active Markets for Identical Assets (Level 1)
Employee benefit plans
Fair value of plan assets	22.5	7.1
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fixed income common trust funds
Employee benefit plans
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Commingled global fund allocation
Employee benefit plans
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Global equity common trust funds
Employee benefit plans
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Government securities
Employee benefit plans
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Non-U.S. Government securities
Employee benefit plans
Fair value of plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Short-term investments
Employee benefit plans
Fair value of plan assets	22.5	7.1
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Observable Inputs (Level 2)
Employee benefit plans
Fair value of plan assets	454.7	433.7
Significant Observable Inputs (Level 2) \| Fixed income common trust funds
Employee benefit plans
Fair value of plan assets	315.4	255.6
Significant Observable Inputs (Level 2) \| Commingled global fund allocation
Employee benefit plans
Fair value of plan assets	81.7	110.3
Significant Observable Inputs (Level 2) \| Global equity common trust funds
Employee benefit plans
Fair value of plan assets	32.1	30.1
Significant Observable Inputs (Level 2) \| U.S. Government securities
Employee benefit plans
Fair value of plan assets	25.2	24.5
Significant Observable Inputs (Level 2) \| Non-U.S. Government securities
Employee benefit plans
Fair value of plan assets	0.3	13.2
Significant Observable Inputs (Level 2) \| Short-term investments
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Observable Inputs (Level 2) \| Other
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3)
Employee benefit plans
Fair value of plan assets	0.9	0.9
Significant Unobservable Inputs (Level 3) \| Fixed income common trust funds
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Commingled global fund allocation
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Global equity common trust funds
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| U.S. Government securities
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Non-U.S. Government securities
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Short-term investments
Employee benefit plans
Fair value of plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Other
Employee benefit plans
Fair value of plan assets	$ 0.9	$ 0.9
United States
Employee benefit plans
Actual Allocations	100.00%	100.00%
Mid-point of Target Allocation Range	100.00%
Fair value of plan assets	$ 279.8	$ 263.6	$ 238.0
Actual return on plan assets	$ 35.1	$ 35.7
United States \| Fixed income common trust funds
Employee benefit plans
Actual Allocations	68.00%	67.00%
Mid-point of Target Allocation Range	65.00%
United States \| Commingled global fund allocation
Employee benefit plans
Actual Allocations	11.00%	17.00%
Mid-point of Target Allocation Range	18.00%
United States \| Global equity common trust funds
Employee benefit plans
Actual Allocations	5.00%	5.00%
Mid-point of Target Allocation Range	5.00%
United States \| U.S. Government securities
Employee benefit plans
Actual Allocations	9.00%	9.00%
Mid-point of Target Allocation Range	10.00%
United States \| Short-term investments
Employee benefit plans
Actual Allocations	7.00%	2.00%
Mid-point of Target Allocation Range	2.00%
Foreign Plan
Employee benefit plans
Actual Allocations	100.00%	100.00%
Mid-point of Target Allocation Range	100.00%
Fair value of plan assets	$ 198.3	$ 178.1	$ 159.2
Actual return on plan assets	$ 19.9	$ 19.4
Foreign Plan \| Fixed income common trust funds
Employee benefit plans
Actual Allocations	65.00%	45.00%
Mid-point of Target Allocation Range	66.00%
Foreign Plan \| Commingled global fund allocation
Employee benefit plans
Actual Allocations	25.00%	37.00%
Mid-point of Target Allocation Range	25.00%
Foreign Plan \| Global equity common trust funds
Employee benefit plans
Actual Allocations	9.00%	10.00%
Mid-point of Target Allocation Range	9.00%
Foreign Plan \| Non-U.S. Government securities
Employee benefit plans
Actual Allocations	0.00%	7.00%
Mid-point of Target Allocation Range	0.00%
Foreign Plan \| Short-term investments
Employee benefit plans
Actual Allocations	1.00%	1.00%
Mid-point of Target Allocation Range	0.00%