Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	$ 582.9
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Assets Transferred into (out of) Level 3	(22.3)	$ 0.0
Fair Value of Plan Assets (Period End)	367.6	582.9
Investment funds
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	14.1
Fair Value of Plan Assets (Period End)	10.6	14.1
Limited partnerships
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	24.0
Fair Value of Plan Assets (Period End)	0.0	24.0
Fixed income securities
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	29.0
Fair Value of Plan Assets (Period End)	12.5	29.0
Insurance contracts
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	2.0
Fair Value of Plan Assets (Period End)	1.6	2.0
Other plan assets
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	30.7
Fair Value of Plan Assets (Period End)	11.9	30.7
Total plan assets subject to leveling
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	99.8
Fair Value of Plan Assets (Period End)	36.6	99.8
Investments measured at net asset value
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	483.1
Fair Value of Plan Assets (Period End)	331.0	483.1
Level 1 \| Investment funds
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	14.1
Fair Value of Plan Assets (Period End)	10.6	14.1
Level 1 \| Limited partnerships
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 1 \| Fixed income securities
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	29.0
Fair Value of Plan Assets (Period End)	12.5	29.0
Level 1 \| Insurance contracts
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 1 \| Other plan assets
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	30.7
Fair Value of Plan Assets (Period End)	11.9	30.7
Level 1 \| Total plan assets subject to leveling
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	73.8
Fair Value of Plan Assets (Period End)	35.0	73.8
Level 2 \| Investment funds
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 2 \| Limited partnerships
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 2 \| Fixed income securities
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 2 \| Insurance contracts
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	2.0
Fair Value of Plan Assets (Period End)	1.6	2.0
Level 2 \| Other plan assets
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 2 \| Total plan assets subject to leveling
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	2.0
Fair Value of Plan Assets (Period End)	1.6	2.0
Level 3 \| Investment funds
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 3 \| Limited partnerships
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	24.0	25.9
Actual return on plan assets	(1.7)	(1.9)
Fair Value of Plan Assets (Period End)	0.0	24.0
Level 3 \| Fixed income securities
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 3 \| Insurance contracts
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 3 \| Other plan assets
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	0.0
Fair Value of Plan Assets (Period End)	0.0	0.0
Level 3 \| Total plan assets subject to leveling
Fair value assets and liabilities measured on recurring basis
Fair Value of Plan Assets (Period Start)	24.0
Fair Value of Plan Assets (Period End)	$ 0.0	$ 24.0

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

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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

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs.

+ References

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- Definition

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No definition available.

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