Acquisitions and disposals - Acquisitions (Details) - EUR (€) € in Millions	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Acquisitions
Net cash acquired	€ (2)	€ (126)
Total cash consideration paid and net cash acquired	136	10,295
European Liberty Global assets
Acquisitions
Total cash consideration paid and net cash acquired	0	10,313
Other acquisitions
Acquisitions
Total cash consideration paid and net cash acquired	€ 138	€ 108

The amount of cash and cash equivalents in subsidiaries or other businesses over which control is obtained or lost. [Refer: Subsidiaries [member]; Cash and cash equivalents]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 40
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_40_c&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_CashAndCashEquivalentsInSubsidiaryOrBusinessesAcquiredOrDisposed2013
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration