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.

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.

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- Definition

Notice period the entity is required to deliver before it can redeem an investment calculated using net asset value per share, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, investments calculated by per unit, per membership interest, other equity or ownership interest and alternative investments.

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- Definition

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

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Employee Benefits - Summary of Assets for Reported NAV Used to Estimate Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair Value	$ 1,190.7	$ 900.0	$ 874.9
Fair Value, Measurements, Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair Value	1,190.7	900.0
Fair Value, Measurements, Recurring \| Net Asset Value per Share
Defined Benefit Plan Disclosure [Line Items]
Fair Value	285.3	536.2
Fair Value, Measurements, Recurring \| Private Equities
Defined Benefit Plan Disclosure [Line Items]
Unfunded Commitments	1.5	1.7
Fair Value, Measurements, Recurring \| Private Equities \| Net Asset Value per Share
Defined Benefit Plan Disclosure [Line Items]
Fair Value	119.0	127.0
Fair Value, Measurements, Recurring \| Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Unfunded Commitments		4.1
Fair Value, Measurements, Recurring \| Fixed Income \| Net Asset Value per Share
Defined Benefit Plan Disclosure [Line Items]
Fair Value	$ 30.5	231.4
Fair Value, Measurements, Recurring \| Fixed Income \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Redemption Notice Period	35 days
Fair Value, Measurements, Recurring \| Fixed Income \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Redemption Notice Period	90 days
Fair Value, Measurements, Recurring \| Equities \| Net Asset Value per Share
Defined Benefit Plan Disclosure [Line Items]
Fair Value	$ 58.3	$ 81.9
Fair Value, Measurements, Recurring \| Equities \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Redemption Notice Period	3 days	0 days
Fair Value, Measurements, Recurring \| Equities \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Redemption Notice Period	30 days	30 days
Fair Value, Measurements, Recurring \| Absolute Return \| Net Asset Value per Share
Defined Benefit Plan Disclosure [Line Items]
Fair Value	$ 77.5	$ 95.9
Fair Value, Measurements, Recurring \| Absolute Return \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Redemption Notice Period	3 days	3 days
Fair Value, Measurements, Recurring \| Absolute Return \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Redemption Notice Period	75 days	75 days