Derivatives - Summary Of Gain Loss On Fair Value Hedge ineffectiveness (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair value hedges [member]
Disclosure Of Gain Loss On Fair Value Hedge Ineffectiveness [Line Items]
Gains (losses) related to the ineffectiveness portion of designated fair value hedges	€ 1	€ 0	€ 1

The gain (loss) on hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 24C
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2021-en-r&anchor=para_24C_a_i&doctype=Standard
-URIDate 2021-03-24

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration