Junior Subordinated Debt Securities (Junior Subordinated Debt Securities) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (101)	$ (108)
Junior Subordinated Notes	3,164	3,161
MetLife Inc $500M Maturing 2069 [Member]
Debt Instrument [Line Items]
Face Value	500	500
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (5)	(5)
Debt Instrument, Interest Rate, Stated Percentage	10.75%
Debt Instrument, Interest Rate Terms	SOFR + 0.26161% + 7.548%
Junior Subordinated Notes	$ 495	495
Senior notes
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (99)	(106)
Debt Instrument, Interest Rate, Stated Percentage	5.70%
MetLife Capital Trust X $750M Maturing 2068 [Member]
Debt Instrument [Line Items]
Face Value	$ 750	750
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (7)	(8)
Debt Instrument, Interest Rate, Stated Percentage	9.25%
Debt Instrument, Interest Rate Terms	SOFR + 0.26161% + 5.540%
Junior Subordinated Notes	$ 743	742
MetLife Capital Trust IV $700M Maturing 2067 [Member]
Debt Instrument [Line Items]
Face Value	700	700
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (11)	(12)
Debt Instrument, Interest Rate, Stated Percentage	7.875%
Debt Instrument, Interest Rate Terms	SOFR + 0.26161% + 3.960%
Junior Subordinated Notes	$ 689	688
MetLife Inc $1,250M Maturing 2066 [Member]
Debt Instrument [Line Items]
Face Value	1,250	1,250
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (13)	(14)
Debt Instrument, Interest Rate, Stated Percentage	6.40%
Debt Instrument, Interest Rate Terms	SOFR + 0.26161% + 2.205%
Junior Subordinated Notes	$ 1,237	1,236
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Face Value	3,200	3,200
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (36)	$ (39)

Face (par) amount of debt instrument at time of issuance.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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