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

The total recognized during the period for income on leases meeting the criteria for classification as direct financing lease.

No definition available.

Name:	met_DirectFinancingLeasesIncomeStatementNetIncomeFromDirectFinancingLeases
Namespace Prefix:	met_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Revenue realized in the period on direct financing leases.

No definition available.

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

Pretax lease income allocated in proportionate amounts from unearned income.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=7662751&loc=d3e45152-112736

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

The tax effect from the current year income from arrangements meeting the criteria for classification as a leveraged lease.

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

The total recognized during the period for income on leases meeting the criteria for classification as leveraged leases.