Segment Information (Narrative) (Details) $ in Millions		12 Months Ended
	Mar. 31, 2020 USD ($) customer	Mar. 31, 2021 USD ($) customer	Mar. 31, 2020 USD ($) customer	Mar. 31, 2019 USD ($) customer
Concentration Risk [Line Items]
Revenues		$ 3,271.5	$ 3,890.0	$ 3,680.5
Customer Concentration Risk | Sales Revenue, Net
Concentration Risk [Line Items]
Number of customers over 10% threshold | customer		1	1	1
Revenues		$ 638.8	$ 438.6	$ 401.9
Customer Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Number of customers over 10% threshold | customer	1
Percentage of consolidated gross accounts receivable attributable to customer over threshold	11.00%
Accounts receivable, gross	$ 82.0		$ 82.0