Deferred and current taxation - Credited to other comprehensive income (Details) - EUR (€) € in Millions	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Deferred tax applicable to items charged or credited to other comprehensive income
Derivative financial instruments	€ (94.7)	€ 91.2	€ (87.0)
Total tax charge in other comprehensive income	€ (94.7)	€ 91.2	€ (87.0)

The amount of income tax relating to amounts recognised in other comprehensive income in relation to changes in the fair value of financial liabilities attributable to a change in the credit risk of those liabilities. [Refer: Credit risk [member]; Other comprehensive income]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2019-01-01
-Paragraph 81
-Subparagraph ab
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_81_ab&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 90
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_90&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_IncomeTaxRelatingToChangesInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiabilityOfOtherComprehensiveIncome
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration