Equity (Statutory Equity & Income - Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Principal U.S. Insurance Subsidiaries, Excluding American Life
Statutory Accounting Practices [Line Items]
Combined RBC ratio of the principal U.S. insurance subsidiaries	in excess of 340%	in excess of 360%
Metropolitan Life Insurance Company
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Prescribed Practice, Amount	$ 1,300	$ 1,200
Statutory Accounting Practices, Statutory Net Income Amount	2,737	3,513	$ 3,392
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	10,869	11,804
MetLife Reinsurance Company of Vermont
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Prescribed Practice, Amount	2,000	2,000
MetLife's Domestic Captive Life Reinsurance Subsidiaries
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Net Income Amount	44	41	$ (7)
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 726	$ 693
Japan
Statutory Accounting Practices [Line Items]
Adjusted capital	in excess of three times	in excess of four times the 200% solvency margin ratio
Other Foreign Operations, Excluding Japan
Statutory Accounting Practices [Line Items]
Statutory capital and surplus required	$ 3,300
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 7,400