Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock, Common	Accumulated Other Comprehensive Income (Loss)	Total MetLife, Inc.'s Stockholders' Equity	Total MetLife, Inc.'s Stockholders' Equity Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests
Beginning Balance at Dec. 31, 2022	$ 30,125		$ 0	$ 12	$ 33,616	$ 40,332		$ (21,458)	$ (22,621)	$ 29,881		$ 244
Treasury stock acquired in connection with share repurchases	(1,465)							(1,465)		(1,465)
Share Repurchase Program, Excise Tax	13
Stock-based compensation	14				14					14
Dividends on preferred stock	(98)					(98)				(98)
Dividends on common stock	$ (788)					(788)				(788)
Dividend Per Share	$ 1.020
Change in equity of noncontrolling interests	$ (8)									0		(8)
Net income (loss)	493					482				482		11
Other comprehensive income (loss), net of income tax	2,219								2,235	2,235		(16)
Ending Balance at Jun. 30, 2023	30,492		0	12	33,630	39,928		(22,923)	(20,386)	30,261		231
Beginning Balance at Dec. 31, 2022	30,125		0	12	33,616	40,332		(21,458)	(22,621)	29,881		244
Dividends on preferred stock	(165)
Net income (loss)	988
Ending Balance at Sep. 30, 2023	25,895		0	12	33,666	39,958		(23,724)	(24,254)	25,658		237
Beginning Balance at Jun. 30, 2023	30,492		0	12	33,630	39,928		(22,923)	(20,386)	30,261		231
Treasury stock acquired in connection with share repurchases	(801)							(801)		(801)
Share Repurchase Program, Excise Tax	9
Stock-based compensation	36				36					36
Dividends on preferred stock	(67)					(67)				(67)
Dividends on common stock	$ (392)					(392)				(392)
Dividend Per Share	$ 0.520
Net income (loss)	$ 495					489				489		6
Other comprehensive income (loss), net of income tax	(3,868)								(3,868)	(3,868)		0
Ending Balance at Sep. 30, 2023	25,895		0	12	33,666	39,958		(23,724)	(24,254)	25,658		237
Beginning Balance at Dec. 31, 2023	30,253	$ (219)	0	12	33,690	40,146	$ (219)	(24,591)	(19,242)	30,015	$ (219)	238
Treasury stock acquired in connection with share repurchases	(2,046)							(2,046)		(2,046)
Share Repurchase Program, Excise Tax	19
Stock-based compensation	50				50					50
Dividends on preferred stock	(101)					(101)				(101)
Dividends on common stock	$ (766)					(766)				(766)
Dividend Per Share	$ 1.065
Change in equity of noncontrolling interests	$ 33									0		33
Net income (loss)	1,828					1,813				1,813		15
Other comprehensive income (loss), net of income tax	(1,492)								(1,494)	(1,494)		2
Ending Balance at Jun. 30, 2024	27,540		0	12	33,740	40,873		(26,637)	(20,736)	27,252		288
Beginning Balance at Dec. 31, 2023	30,253	$ (219)	0	12	33,690	40,146	$ (219)	(24,591)	(19,242)	30,015	$ (219)	238
Dividends on preferred stock	(168)
Net income (loss)	3,169
Ending Balance at Sep. 30, 2024	31,164		0	12	33,766	41,765		(27,418)	(17,240)	30,885		279
Beginning Balance at Jun. 30, 2024	27,540		0	12	33,740	40,873		(26,637)	(20,736)	27,252		288
Treasury stock acquired in connection with share repurchases	(781)							(781)		(781)
Share Repurchase Program, Excise Tax	7
Stock-based compensation	26				26					26
Dividends on preferred stock	(67)					(67)				(67)
Dividends on common stock	$ (383)					(383)				(383)
Dividend Per Share	$ 0.545
Change in equity of noncontrolling interests	$ (9)									0		(9)
Net income (loss)	1,341					1,342				1,342		(1)
Other comprehensive income (loss), net of income tax	3,497								3,496	3,496		1
Ending Balance at Sep. 30, 2024	$ 31,164		$ 0	$ 12	$ 33,766	$ 41,765		$ (27,418)	$ (17,240)	$ 30,885		$ 279