This represents the recorded investment for impaired mortgage loans held-for-investment.

Name:	met_RecordedInvestmentForImpairedMortgageLoansHeldForInvestment
Namespace Prefix:	met
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6873192&loc=d3e21338-158488

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesRealEstate
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The recorded investment related to impaired financing receivables.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953550-111524

-Subparagraph (b)

+ Details

Name:	us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The unpaid principal balance related to impaired financing receivables.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5212-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_LoanAndLeaseReceivablesImpairedAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Investments (Details 36) (USD $) In Millions	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Dec. 31, 2009
Impaired Mortgage Loans
Unpaid Principal Balance	$ 706		$ 507
Valuation allowances	529	566	664	666	734	721
Carrying value	574		403
Commercial mortgage loans portfolio segment [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	451		219
Valuation allowances	428	469	562	573	621	589
Carrying value	369		171
Commercial mortgage loans portfolio segment [Member] \| Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	211		120
Recorded Investment	211		120
Valuation allowances	70		36
Carrying value	141		84
Commercial mortgage loans portfolio segment [Member] \| Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	240		99
Carrying value	228		87
Agricultural mortgage loans portfolio segment [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	234		269
Valuation allowances	82	79	88	76	96	115
Carrying value	185		213
Agricultural mortgage loans portfolio segment [Member] \| Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	150		146
Recorded Investment	150		146
Valuation allowances	46		52
Carrying value	104		94
Agricultural mortgage loans portfolio segment [Member] \| Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	84		123
Carrying value	81		119
Residential mortgage loans portfolio segment [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	21		19
Valuation allowances	19	18	14	17	17	17
Carrying value	20		19
Residential mortgage loans portfolio segment [Member] \| Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	7		3
Recorded Investment	7		3
Valuation allowances	1		0
Carrying value	6		3
Residential mortgage loans portfolio segment [Member] \| Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	14		16
Carrying value	14		16
Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	368		269
Recorded Investment	368		269
Valuation allowances	117		88
Carrying value	251		181
Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	338		238
Carrying value	$ 323		$ 222