Special Charges and Other, Net - Roll Forward of Accrued Restructuring and Other Exit Cost Charges (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 47.8	$ 47.2
Additions due to Microsemi acquisition		19.4
Charges	19.4	44.2
Payments	(21.1)	(64.3)
Non-cash - Other	(9.3)	1.4
Changes in foreign exchange rates		(0.1)
Effect of adoption of ASC 842	(12.5)
Restructuring reserve, ending balance	24.3	47.8
Current	7.9
Non-current	16.4
Restructuring Employee Separation Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	12.9	0.8
Additions due to Microsemi acquisition		10.4
Charges	6.0	48.9
Payments	(11.6)	(47.1)
Non-cash - Other	(1.2)	0.0
Changes in foreign exchange rates		(0.1)
Effect of adoption of ASC 842	0.0
Restructuring reserve, ending balance	6.1	12.9
Restructuring Exit Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	19.2	27.3
Additions due to Microsemi acquisition		9.0
Charges	13.4	(4.7)
Payments	(5.2)	(13.1)
Non-cash - Other	(8.7)	0.7
Changes in foreign exchange rates		0.0
Effect of adoption of ASC 842	(12.5)
Restructuring reserve, ending balance	6.2	19.2
Non-Restructuring Exit Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	15.7	19.1
Additions due to Microsemi acquisition		0.0
Charges	0.0	0.0
Payments	(4.3)	(4.1)
Non-cash - Other	0.6	0.7
Changes in foreign exchange rates		0.0
Effect of adoption of ASC 842	0.0
Restructuring reserve, ending balance	$ 12.0	$ 15.7

Restructuring Reserve, Settled Without Cash And Other Adjustments

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- Definition

Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements.

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- Definition

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.

+ References

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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.

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Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

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Carrying amount as of the balance sheet date of known and estimated obligations associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid in the next twelve months or in the normal operating cycle if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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Carrying amount as of the balance sheet date of known and estimated costs associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid after one year or beyond the next operating cycle, if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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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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Amount of foreign currency translation gain (loss) which decreases (increases) the restructuring reserve.

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