Investments (Other Invested Assets - Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Carrying value of Tax Credits	$ 759	$ 947
Losses From Tax Credits	$ 174	$ 195	$ 226

This caption discloses the carrying value amount of tax credits partnerships guaranteed by third parties included within net investment income.

No definition available.

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