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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.

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Amount of financing receivable originated five or more years prior to latest fiscal year.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount of financing receivable originated four years prior to latest fiscal year.

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Amount of financing receivable originated in current fiscal year.

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Amount of financing receivable originated in fiscal year prior to latest fiscal year.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919232-210447

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922352-210448

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Amount of financing receivable originated three years prior to latest fiscal year.

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Amount of financing receivable originated two years prior to latest fiscal year.

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Amount of financing receivable that can be withdrawn, repaid and redrawn.

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Balance Type:	debit
Period Type:	instant

Amount, before allowance for credit loss, of financing receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	na
Balance Type:
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Name:	us-gaap_InternalCreditAssessmentAxis=met_MortgageLoansByCreditQualityIndicatorRangeThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_InternalCreditAssessmentAxis=met_MortgageLoansByCreditQualityIndicatorRangeFourMember
Namespace Prefix:
Data Type:	na
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