XML 122 R109.htm IDEA: XBRL DOCUMENT
v3.24.3

Fair Value (Quantitative Information) (Details) | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Minimum | Interest rate | Measurement Input, Swap Yield |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative Asset (Liability) Net, Measurement Input | 0 | 367
Minimum | Foreign currency exchange rate | Measurement Input, Swap Yield |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative Asset (Liability) Net, Measurement Input | 111 | 185
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 0 - 40 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0 | 0
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 41 - 60 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0004 | 0.0004
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 61 - 115 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0 | 0
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 1 - 10 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0014 | 0.0039
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 11 - 20 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0039 | 0.0039
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 21 - 116 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0039 | 0.0010
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Utilization Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0020 | 0.0020
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Withdrawal Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0 | 0
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Long-Term Equity Volatility |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.1423 | 0.0805
Minimum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Nonperformance risk spread |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0011 | 0.0038
Minimum | U.S. corporate and foreign corporate | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 34 | 4
Minimum | U.S. corporate and foreign corporate | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 13 | 0
Minimum | U.S. corporate and foreign corporate | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 92 | 86
Minimum | RMBS | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 0 | 0
Minimum | ABS & CLO | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 3 | 3
Maximum | Interest rate | Measurement Input, Swap Yield |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative Asset (Liability) Net, Measurement Input | 0 | 399
Maximum | Foreign currency exchange rate | Measurement Input, Swap Yield |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative Asset (Liability) Net, Measurement Input | 168 | 399
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 0 - 40 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0015 | 0.0015
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 41 - 60 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0079 | 0.0075
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 61 - 115 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 1 | 1
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 1 - 10 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.2010 | 0.2010
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 11 - 20 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.15 | 0.15
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 21 - 116 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.15 | 0.15
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Utilization Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.22 | 0.22
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Withdrawal Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.20 | 0.20
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Long-Term Equity Volatility |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.2227 | 0.2185
Maximum | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Nonperformance risk spread |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0149 | 0.0159
Maximum | U.S. corporate and foreign corporate | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 133 | 131
Maximum | U.S. corporate and foreign corporate | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 116 | 110
Maximum | U.S. corporate and foreign corporate | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 100 | 102
Maximum | RMBS | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 121 | 112
Maximum | ABS & CLO | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 106 | 101
Weighted Average | Interest rate | Measurement Input, Swap Yield |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative Asset (Liability) Net, Measurement Input | 0 | 385
Weighted Average | Foreign currency exchange rate | Measurement Input, Swap Yield |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative Asset (Liability) Net, Measurement Input | 166 | 193
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 0 - 40 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0005 | 0.0005
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 41 - 60 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0022 | 0.0022
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 61 - 115 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0114 | 0.0123
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 1 - 10 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.1286 | 0.0872
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 11 - 20 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0605 | 0.0434
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 21 - 116 |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0820 | 0.0459
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Utilization Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0079 | 0.0044
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Withdrawal Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0477 | 0.0447
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Long-Term Equity Volatility |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.1877 | 0.1855
Weighted Average | Market Risk Benefits and Reinsured Market Risk Benefits direct, assumed and ceded guaranteed minimum benefits | Nonperformance risk spread |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
MRBs and Reinsured MRBs direct, assumed and ceded guaranteed minimum benefits | 0.0064 | 0.0073
Weighted Average | U.S. corporate and foreign corporate | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 94 | 93
Weighted Average | U.S. corporate and foreign corporate | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 97 | 92
Weighted Average | U.S. corporate and foreign corporate | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 96 | 96
Weighted Average | RMBS | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 95 | 93
Weighted Average | ABS & CLO | Valuation Technique, Market Approach | Measurement Input, Quoted Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Debt Securities, Available-for-sale, Measurement Input | 97 | 93

X
- Definition Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Value of input used to measure net derivative asset (liability). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_DerivativeAssetLiabilityNetMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of measurement input used to measure contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_MarketRiskBenefitMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_MeasurementInputSwapYieldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=met_MarketRiskBenefitFinancialInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_MortalityRatesRangeOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_MortalityRatesRangeTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_MortalityRatesRangeThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_LapseRatesDurationRangeOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_LapseRatesDurationRangeTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_LapseRatesDurationRangeThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputUtilizationRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputWithdrawalRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=met_MeasurementInputLongTermEquityVolatilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputCounterpartyCreditRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueMatrixPricingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputOfferedPriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputQuotedPriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueConsensusPricingModelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |