Name:	met_CededCreditRiskReinsuranceRecoverablesNet
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Percentage of total reinsurance recoverables which constitute a concentration of credit risk.

No definition available.

Name:	met_CededCreditRiskReinsuranceRecoverablesPercentage
Namespace Prefix:	met_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Amount of reinsurance recoverable balances in both asset and liability accounts that have been ceded.

No definition available.

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

Stated amount that is the upper retention limit per company policy.

No definition available.

Name:	met_ReinsuranceRetentionPolicyAmountRetained
Namespace Prefix:	met_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Percentage of risk reinsured in excess of stated retention per company policy.

No definition available.

Name:	met_ReinsuranceRetentionPolicyExcessRetentionPercentage
Namespace Prefix:	met_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	met_ReinsuranceRetentionPolicyLineItems
Namespace Prefix:	met_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of risk reinsured on insurance products per company policy.

No definition available.

Name:	met_ReinsuranceRetentionPolicyReinsuredRiskPercentage
Namespace Prefix:	met_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

Carrying amount of assets as of the balance sheet date pertaining to amounts paid by the insured (including a ceding company) under insurance or reinsurance contracts for which insurance risk is not transferred.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 340

-SubTopic 30

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6387650&loc=d3e9420-108338

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 98-7

-Paragraph 18

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
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Carrying amount of liabilities as of the balance sheet date pertaining to amounts received by the insurer or reinsurer from the insured (including a ceding company) under insurance or reinsurance contracts for which insurance risk is not transferred.