Commitments, contingent liabilities and legal proceedings - Indus Tower merger (Details) - EUR (€) € in Millions	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Contingent liabilities and legal proceedings
Initial dividend paid	€ 2,796	€ 2,665	€ 4,624

The amount of dividends recognised as distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 107
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_107&doctype=Standard
-URIDate 2020-01-01

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