Transfers of Financial Assets - Additional Information (Detail) - EUR (€) € in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of financial assets [line items]
Amount of collateral pledged for derivative transactions	€ 2,300	€ 2,300
The Netherlands [member]
Disclosure of financial assets [line items]
Mortgage loan pledged as security for notes issued	5,100	4,400
CA [member] \| SAECURE 17 [member] \| Life reinsurance contracts [member]
Disclosure of financial assets [line items]
Collateral posted	€ 600	€ 575

The amount of financial assets that the entity has pledged as collateral for liabilities or contingent liabilities, including amounts that have been reclassified in accordance with paragraph 3.2.23(a) of IFRS 9. [Refer: Contingent liabilities [member]; Financial assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 14
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2021-en-r&anchor=para_14_a&doctype=Standard
-URIDate 2021-03-24

Name:	ifrs-full_FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant