Financial Risks - Summary of Composition by Industry Category of Available-for-Sale (AFS) Debt Securities, Money Market Investments and Other in an Unrealized Loss Position (Detail) - EUR (€) € in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	€ 28,943	€ 13,858
Unrealized losses	(1,550)	(493)
Residential mortgage- backed securities [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	446	732
Unrealized losses	(30)	(30)
Commercial mortgage- backed securities (CMBSs) [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	2,012	1,140
Unrealized losses	(45)	(22)
Asset backed securities [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	2,088	87
Unrealized losses	(42)	(2)
ABSs - other [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	829	603
Unrealized losses	(10)	(13)
Financial Industry - Banking [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	2,522	663
Unrealized losses	(106)	(39)
Financial Industry - Insurance [Member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	646	231
Unrealized losses	(36)	(7)
Financial Industry - Other [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	1,523	1,411
Unrealized losses	(69)	(10)
Industrial [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	10,073	3,305
Unrealized losses	(684)	(131)
Utility [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	1,258	375
Unrealized losses	(78)	(14)
Government Securities [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	2,935	3,438
Unrealized losses	(164)	(122)
Other securities [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	194	193
Unrealized losses	(88)	(73)
Held by Aegon Americas and NL [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	24,528	12,179
Unrealized losses	(1,352)	(462)
Held by other segments [member]
Disclosure of unrealized losses - debt securities, money market investments and other [line items]
Carrying value of instruments with unrealized losses	4,415	1,680
Unrealized losses	€ (197)	€ (31)