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

Cumulative net cash outflow paid to the unaffiliated financial institution as a result of continued fluctuation in the estimated fair value of the debt instrument as of the balance sheet date.

No definition available.

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

Cash received (paid) in connection with the change in market value of collateral used to secure debt.

No definition available.

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

Collateral Financing Arrangements.

No definition available.

Name:	met_CollateralFinancingArrangementsTextualsAbstract
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Debt Instrument, Term in Years.

No definition available.

Name:	met_DebtInstrumentTermInYears
Namespace Prefix:	met_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The element presents the invested assets on deposit, held in trust and pledged as collateral.

No definition available.

Name:	met_InvestedAssetsOnDepositHeldInTrustAndPledgedAsCollateral
Namespace Prefix:	met_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Name:	us-gaap_DebtInstrumentFaceAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateTerms
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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

The increase (decrease) during the reporting period in other amounts due to the reporting entity, which are not otherwise defined in the taxonomy.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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Name:	us-gaap_IncreaseDecreaseInOtherReceivables
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

The fair value, as of the date of each statement of financial position presented, of securities that are restricted as collateral for the payment of other debt obligations, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
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-URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728

Name:	us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForOtherDebtObligationsAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

No definition available.

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_LongtermDebtTypeAxis=met_CashReceivedPaidCollateralFinancingArrangementsMRCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

Name:	us-gaap_DebtInstrumentAxis=met_SecuredDebtMrcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=met_SecuredDebtMrscMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	met_CumulativeRepaymentAxis=met_CumulativeRepaymentMember
Namespace Prefix:
Data Type:	na
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Period Type: