Additional Financial Information (Other Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2018		Apr. 01, 2018	[1]	Mar. 31, 2018
Other current assets
Prepaid expenses and other	$ 64.0				$ 34.1
Product inventory	20.8				20.3
Tax credits receivable	106.2				141.4
Other current assets	191.0				195.8
Other non-current assets
Prepaid expenses and other	52.1				23.8
Accounts receivable	266.4	[1]	$ 257.7		325.2
Tax credits receivable	121.1				109.6
Other non-current assets	$ 439.6				$ 458.6

[1] Included in accounts receivable within non-current other assets in the unaudited condensed consolidated balance sheets.