Supplemental Financial Statement Information - Severance and Employee Benefit Costs Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Restructuring Reserve [Roll Forward]
Balance at December 31, 2020	$ 43.4
Additions	0.0	$ 8.0
Payments	(6.5)
Balance at March 31, 2021	$ 36.9

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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