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

No definition available.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953550-111524

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ 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=7512638&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, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Impaired Mortgage Loans
Unpaid Principal Balance	$ 704		$ 593
Valuation allowances	354	361	481	529	566	664
Recorded Investment	586		470
Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	470		269
Recorded Investment	456		268
Valuation allowances	97		105
Recorded Investment	359		163
Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	234		324
Recorded Investment	227		307
Commercial mortgage loans portfolio segment [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	499		348
Valuation allowances	300	300	398	428	469	562
Recorded Investment	413		274
Commercial mortgage loans portfolio segment [Member] \| Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	347		96
Recorded Investment	336		96
Valuation allowances	73		59
Recorded Investment	263		37
Commercial mortgage loans portfolio segment [Member] \| Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	152		252
Recorded Investment	150		237
Agricultural mortgage loans portfolio segment [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	192		231
Valuation allowances	52	59	81	82	79	88
Recorded Investment	162		183
Agricultural mortgage loans portfolio segment [Member] \| Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	110		160
Recorded Investment	107		159
Valuation allowances	22		45
Recorded Investment	85		114
Agricultural mortgage loans portfolio segment [Member] \| Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	82		71
Recorded Investment	77		69
Residential mortgage loans portfolio segment [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	13		14
Valuation allowances	2	2	2	19	18	14
Recorded Investment	11		13
Residential mortgage loans portfolio segment [Member] \| Loans with a Valuation Allowance [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	13		13
Recorded Investment	13		13
Valuation allowances	2		1
Recorded Investment	11		12
Residential mortgage loans portfolio segment [Member] \| Loans Without Valuation Allowances [Member]
Impaired Mortgage Loans
Unpaid Principal Balance	0		1
Recorded Investment	$ 0		$ 1