| Document and Entity Information | Jun. 20, 2023 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | METLIFE INC |
| Amendment Flag | true |
| Entity Central Index Key | 0001099219 |
| Document Type | 8-K/A |
| Document Period End Date | Jun. 20, 2023 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-15787 |
| Entity Tax Identification Number | 13-4075851 |
| Entity Address, Address Line One | 200 Park Avenue |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10166-0188 |
| City Area Code | (212) |
| Local Phone Number | 578-9500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Description | In the proxy statement that MetLife, Inc. (the “Company”) provided to shareholders in connection with the Company’s 2023 annual meeting of common shareholders (the “Annual Meeting”), the Company’s Board of Directors recommended that the shareholders vote, on an advisory basis, in favor of an annual frequency for future “say-on-pay” votes. Say-on-pay votes are periodic, non-binding shareholder votes to approve the compensation paid to the Company’s named executive officers as disclosed in the Company’s proxy statements and are required under Section 14A of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). At the Annual Meeting on June 20, 2023, approximately 99% of the shares voting on the matter voted in favor of an annual frequency for say-on-pay votes. On October 3, 2023, the Company’s Board of Directors approved an annual frequency for future say-on-pay votes. As a result, the Company expects that a say-on-pay vote will be held each year through 2029, when the next shareholder vote on the frequency of say-on-pay votes is required under the Exchange Act. The Company disclosed the results of the shareholder votes at the Annual Meeting on a Current Report on Form 8-K filed on June 23, 2023 (the “Original Report”). This Current Report on Form 8-K/A amends the Original Report solely for the purpose of disclosing the Company’s decision on the frequency of future say-on-pay votes. |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, par value $0.01 |
| Trading Symbol | MET |
| Security Exchange Name | NYSE |
| Series A Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Floating Rate Non-Cumulative Preferred Stock, Series A, par value $0.01 |
| Trading Symbol | MET PRA |
| Security Exchange Name | NYSE |
| Series E Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares, each representing a 1/1,000th interest in a share of 5.625% Non-Cumulative Preferred Stock, Series E |
| Trading Symbol | MET PRE |
| Security Exchange Name | NYSE |
| Series F Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares, each representing a 1/1,000th interest in a share of 4.75% Non-Cumulative Preferred Stock, Series F |
| Trading Symbol | MET PRF |
| Security Exchange Name | NYSE |
