Financial instruments - Fair values and risk management - Credit risk (Details) € in Millions	12 Months Ended
Mar. 31, 2022 EUR (€) customer	Mar. 31, 2021 EUR (€)	Mar. 31, 2020 EUR (€)
Disclosure of financial assets that are either past due or impaired [line items]
Number of individual customers accounting for a significant portion of total revenue \| customer	0
Financial assets	€ 5,254.8	€ 3,386.2	€ 4,549.5
Authorized period for which group can place funds on deposit	18 months
Trade receivables
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	€ 43.5	18.6	2.3
Past due \| Trade receivables
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	3.6	1.0	3.3
Past due and impaired \| Trade receivables
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	0.0	0.0	0.0
Past due but not impaired \| Trade receivables
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	€ 3.6	€ 1.0	€ 3.3

- Definition

The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

+ References + Details