Equity (Net Unrealized Investment Gains Losses) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Components of net unrealized investment gains (losses) included in accumulated other comprehensive income
Fixed maturity securities AFS	$ (29,262)	$ 29,461	$ 44,415
Derivatives	1,976	2,061	1,924
Other	549	389	267
Subtotal	(26,737)	31,911	46,606
Policyholder liabilities (1)	(1,487)	(4,978)	(10,797)
DAC, VOBA and DSI	4,034	(3,208)	(4,050)
Subtotal	2,547	(8,186)	(14,847)
Deferred income tax benefit (expense)	4,914	(6,031)	(8,009)
Net unrealized investment gains (losses)	(19,276)	17,694	23,750
Net unrealized investment gains (losses) attributable to noncontrolling interests	(18)	(23)	(20)
Net unrealized investment gains (losses) attributable to MetLife, Inc.	$ (19,294)	$ 17,671	$ 23,730