Pension Plans and Other Postretirement Benefit Plans - Net Funded Status of Over-Funded, Underfunded, and Unfunded Pension Plans (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Pension plans and other postretirement benefit plans
Overfunded defined benefit pension plans	$ 21.5	$ 22.5
Underfunded and unfunded defined benefit pension plans	(51.3)	(48.1)
Pension Plans
Pension plans and other postretirement benefit plans
Overfunded defined benefit pension plans	21.5	22.5
Underfunded and unfunded defined benefit pension plans	(51.3)	(48.1)
Pension liabilities included in other current liabilities	(1.3)	(1.3)
Net funded status	(31.1)	(26.9)
Underfunded defined benefit pension plans \| Pension Plans
Pension plans and other postretirement benefit plans
Underfunded and unfunded defined benefit pension plans	(27.8)	(24.2)
Unfunded defined benefit pension plans \| Pension Plans
Pension plans and other postretirement benefit plans
Underfunded and unfunded defined benefit pension plans	$ (23.5)	$ (23.9)

Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as current. Excludes other postretirement benefit plan.

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- Definition

Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as noncurrent. Excludes other postretirement benefit plan.

+ References

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- Definition

Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

+ References

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