Fair Value - Summary of Carrying Amounts of Financial Assets and Financial Liabilities that are Classified as at Fair Value Through Profit or Loss (Detail) - EUR (€) € in Millions	Dec. 31, 2019	Dec. 31, 2018
Financial assets at fair value through profit or loss [member]
Disclosure of fair value financial assets and liabilities [line items]
Trading	€ 10,910	€ 7,355
Designated	234,591	202,165
Financial liabilities at fair value through profit or loss, category [member]
Disclosure of fair value financial assets and liabilities [line items]
Trading	11,175	6,935
Designated	60,417	50,383
Investment contracts for account of policyholders [member] \| Financial assets at fair value through profit or loss [member]
Disclosure of fair value financial assets and liabilities [line items]
Designated	225,788	193,741
Investment contracts for account of policyholders [member] \| Financial liabilities at fair value through profit or loss, category [member]
Disclosure of fair value financial assets and liabilities [line items]
Designated	59,956	49,847
Derivatives with negative values not designated as hedges [member] \| Financial assets at fair value through profit or loss [member]
Disclosure of fair value financial assets and liabilities [line items]
Trading	10,634	7,181
Derivatives with negative values not designated as hedges [member] \| Financial liabilities at fair value through profit or loss, category [member]
Disclosure of fair value financial assets and liabilities [line items]
Trading	11,175	6,935
Borrowings [member] \| Financial liabilities at fair value through profit or loss, category [member]
Disclosure of fair value financial assets and liabilities [line items]
Designated	461	536
Investment income related to general account [member] \| Financial assets at fair value through profit or loss [member]
Disclosure of fair value financial assets and liabilities [line items]
Trading	277	174
Designated	€ 8,803	€ 8,424

Disclosure of fair value financial assets and liabilities.

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- Definition

The amount of financial assets at fair value through profit or loss classified as held for trading. A financial asset is classified as held for trading if: (a) it is acquired principally for the purpose of selling it in the near term; (b) on initial recognition it is part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking; or (c) it is a derivative (except for a derivative that is a financial guarantee contract or a designated and effective hedging instrument). [Refer: At fair value [member]; Financial assets at fair value through profit or loss]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
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-IssueDate 2019-01-01
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-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2021-01-01
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 8
-Subparagraph a
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- Definition

The amount of financial assets at fair value through profit or loss that were designated as such upon initial recognition or subsequently. [Refer: At fair value [member]; Financial assets at fair value through profit or loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 8
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_8_a&doctype=Standard
-URIDate 2019-03-27

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- Definition

The amount of financial liabilities at fair value through profit or loss that meet the definition of held for trading. A financial liability is classified as held for trading if: (a) it is acquired or incurred principally for the purpose of selling or repurchasing it in the near term; (b) on initial recognition it is part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking; or (c) it is a derivative (except for a derivative that is a financial guarantee contract or a designated and effective hedging instrument). [Refer: Financial liabilities at fair value through profit or loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 8
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-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_8_e&doctype=Standard
-URIDate 2019-03-27

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- Definition

The amount of financial liabilities at fair value through profit or loss that were designated as such upon initial recognition or subsequently. [Refer: At fair value [member]; Financial liabilities at fair value through profit or loss]

+ References

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