Name:	met_CashCollateralPaid
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Balance Type:	credit
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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
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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
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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
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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
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Data Type:	xbrli:monetaryItemType
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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
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Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 835
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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
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-Name Accounting Standards Codification
-Topic 210
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-Subparagraph (SX 210.5-02.22(a)(1))
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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
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of increase (decrease) in receivables classified as other.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Name:	us-gaap_IncreaseDecreaseInOtherReceivables
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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
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Topic 942
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
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Name:	us-gaap_InterestExpense
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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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Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
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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
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Name:	us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForOtherDebtObligationsAtFairValue
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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:
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Name:	us-gaap_LongtermDebtTypeAxis=met_CashReceivedPaidCollateralFinancingArrangementsMRCMember
Namespace Prefix:
Data Type:	na
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Period Type:

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
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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:
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Name:	us-gaap_DebtInstrumentAxis=met_SecuredDebtMrscMember
Namespace Prefix:
Data Type:	na
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Name:	met_CumulativeRepaymentAxis=met_CumulativeRepaymentMember
Namespace Prefix:
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