This element represents the aggregate non-cash extraordinary dividend of NELICO paid to parent.

No definition available.

Name:	met_NonCashExtraordinaryDividendPaidtoParent
Namespace Prefix:	met_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the aggregate non-cash extraordinary dividend of GALIC paid to parent.

+ References

No definition available.

+ Details

Name:	met_NonCashExtraordinaryDividendPaidtoParent1
Namespace Prefix:	met_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents disclosure of the aggregate cash dividends paid to the entity by consolidated subsidiaries.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(b))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.9-06)
-URI http://asc.fasb.org/extlink&oid=6882215&loc=d3e537971-122884

+ Details

Name:	us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

+ Details

Name:	us-gaap_Dividends
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_StatutoryAccountingPracticesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of dividends that can be declared or paid without approval of regulatory agency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=met_MetropolitanLifeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=met_AmericanLifeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=met_MetropolitanPropertyAndCasualtyInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=met_MetropolitanTowerLifeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=met_NewEnglandLifeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=met_GeneralAmericanLifeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=met_BrighthouseLifeInsuranceCompanyMember
Namespace Prefix:
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Equity (Dividend Restrictions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Metropolitan Life Insurance Company
Statutory Accounting Practices [Line Items]
Dividends	$ 5,740
Paid	3,600	$ 1,489
Non-Cash Extraordinary Dividend of NELICO	981
Non-Cash Extraordinary Dividend of GALIC	1,200
Metropolitan Life Insurance Company \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			$ 2,723
American Life Insurance Company
Statutory Accounting Practices [Line Items]
Paid	0	0
American Life Insurance Company \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			0
Metropolitan Property and Casualty Insurance Company
Statutory Accounting Practices [Line Items]
Paid	228	235
Metropolitan Property and Casualty Insurance Company \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			98
Metropolitan Tower Life Insurance Company
Statutory Accounting Practices [Line Items]
Paid	60	102
Metropolitan Tower Life Insurance Company \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			66
New England Life Insurance Company
Statutory Accounting Practices [Line Items]
Paid	295	199
New England Life Insurance Company \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			106
General American Life Insurance Company
Statutory Accounting Practices [Line Items]
Paid	0	0
General American Life Insurance Company \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			91
Brighthouse Life Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Paid	$ 261	$ 500
Brighthouse Life Insurance Company [Member] \| Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			$ 473