Goodwill impairment testing attributed to reportable segments.

No definition available.

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

- Definition

Amount of reduction of accumulated impairment, due to the disposal of a business unit.

+ References

No definition available.

+ Details

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

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

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

- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

+ Details

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

- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

+ Details

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

- Definition

Amount after tax of loss recognized that results from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

+ Details

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

- Details

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

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=met_MetlifeAssuranceLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=met_CorporateBenefitFundingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=met_GroupVoluntaryAndWorksiteBenefitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=met_MetLifeBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=met_RetailAnnuitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=met_RetailMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_JP
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Goodwill (Narrative) (Details) (USD $)	12 Months Ended
Goodwill (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Acquisitions (4)		$ 1,141,000,000us-gaap_GoodwillAcquiredDuringPeriod	$ 1,000,000us-gaap_GoodwillAcquiredDuringPeriod
Goodwill	9,872,000,000us-gaap_Goodwill	10,542,000,000us-gaap_Goodwill	9,953,000,000us-gaap_Goodwill	11,935,000,000us-gaap_Goodwill
Impairments	0us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss	1,868,000,000us-gaap_GoodwillImpairmentLoss
Goodwill Disposition	70,000,000	8,000,000
MetLife Assurance Limited [Member]
Goodwill [Line Items]
Goodwill Disposition	60,000,000
Parent Company [Member]
Goodwill [Line Items]
Impairments	0	0	1,384,000,000
Japan
Goodwill [Line Items]
Goodwill	4,400,000,000	4,700,000,000	5,200,000,000
Retail
Goodwill [Line Items]
Acquisitions (4)		0	0
Goodwill	1,433,000,000	1,433,000,000	1,433,000,000	3,125,000,000
Impairments			1,692,000,000
Goodwill impairment testing attributed to reportable segments		34,000,000
Reduction of accumulated impairment		0
Goodwill Disposition	0	0
Group, Voluntary & Worksite Benefits
Goodwill [Line Items]
Acquisitions (4)		0	0
Goodwill	138,000,000	138,000,000	138,000,000	138,000,000
Impairments			0
Goodwill impairment testing attributed to reportable segments		9,000,000
Reduction of accumulated impairment		0
Goodwill Disposition	0	0
Corporate Benefit Funding
Goodwill [Line Items]
Acquisitions (4)		0	0
Goodwill	840,000,000	900,000,000	900,000,000	900,000,000
Impairments			0
Goodwill impairment testing attributed to reportable segments		186,000,000
Reduction of accumulated impairment		0
Goodwill Disposition	60,000,000	0
Corporate Benefit Funding \| MetLife Assurance Limited [Member]
Goodwill [Line Items]
Goodwill Disposition	60,000,000
Corporate & Other
Goodwill [Line Items]
Acquisitions (4)		0	0
Goodwill	229,000,000	229,000,000	229,000,000	405,000,000
Impairments			176,000,000
Reduction of accumulated impairment		65,000,000
Goodwill Disposition	0	0
Retail Segment, Annuities Reporting Unit [Member]
Goodwill [Line Items]
Impairments			1,868,000,000
Goodwill impairment, net of income tax			1,600,000,000
MetLife Bank [Member]
Goodwill [Line Items]
Reduction of accumulated impairment		$ 65,000,000