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 at Cost	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, 2019	$ 66,382	$ (121)	$ 0	$ 12	$ 32,680	$ 33,078	$ (121)	$ (12,678)	$ 13,052	$ 66,144	$ (121)	$ 238
Treasury stock acquired in connection with share repurchases	(500)							(500)		(500)
Stock-based compensation	76				76					76
Dividends on preferred stock	(109)					(109)				(109)
Dividends on common stock	(823)					(823)				(823)
Change in equity of noncontrolling interests	(1)									0		(1)
Net income (loss)	4,551					4,543				4,543		8
Other comprehensive income (loss), net of income tax	5,513								5,511	5,511		2
Preferred stock issuance	$ 972				972					972
Dividend Per Share	$ 0.900
Ending Balance at Jun. 30, 2020	$ 75,940		0	12	33,728	36,568		(13,178)	18,563	75,693		247
Beginning Balance at Dec. 31, 2019	66,382	$ (121)	0	12	32,680	33,078	$ (121)	(12,678)	13,052	66,144	$ (121)	238
Preferred stock redemption premium	(14)
Treasury stock acquired in connection with share repurchases	(580)
Dividends on preferred stock	(168)
Net income (loss)	5,260
Preferred stock issuance	1,961
Ending Balance at Sep. 30, 2020	73,569		0	12	33,744	36,782		(13,258)	16,036	73,316		253
Beginning Balance at Jun. 30, 2020	75,940		0	12	33,728	36,568		(13,178)	18,563	75,693		247
Redemption of preferred stock	(989)				(989)					(989)
Preferred stock redemption premium	(14)					(14)				(14)
Treasury stock acquired in connection with share repurchases	(80)							(80)		(80)
Stock-based compensation	16				16					16
Dividends on preferred stock	(59)					(59)				(59)
Dividends on common stock	(419)					(419)				(419)
Change in equity of noncontrolling interests	3									0		3
Net income (loss)	709					706				706		3
Other comprehensive income (loss), net of income tax	(2,527)								(2,527)	(2,527)		0
Preferred stock issuance	$ 989				989					989
Dividend Per Share	$ 0.460
Ending Balance at Sep. 30, 2020	$ 73,569		0	12	33,744	36,782		(13,258)	16,036	73,316		253
Beginning Balance at Dec. 31, 2020	74,817		0	12	33,812	36,491		(13,829)	18,072	74,558		259
Redemption of preferred stock	(494)				(494)					(494)
Preferred stock redemption premium	(6)					(6)				(6)
Treasury stock acquired in connection with share repurchases	(2,112)							(2,112)		(2,112)
Stock-based compensation	122				122					122
Dividends on preferred stock	(103)					(103)				(103)
Dividends on common stock	(829)					(829)				(829)
Change in equity of noncontrolling interests	15									0		15
Net income (loss)	3,775					3,765				3,765		10
Other comprehensive income (loss), net of income tax	$ (5,762)								(5,763)	(5,763)		1
Dividend Per Share	$ 0.940
Ending Balance at Jun. 30, 2021	$ 69,423		0	12	33,440	39,318		(15,941)	12,309	69,138		285
Beginning Balance at Dec. 31, 2020	74,817		0	12	33,812	36,491		(13,829)	18,072	74,558		259
Preferred stock redemption premium	(6)
Treasury stock acquired in connection with share repurchases	(3,100)
Dividends on preferred stock	(166)
Net income (loss)	5,364
Preferred stock issuance	0
Ending Balance at Sep. 30, 2021	69,333		0	12	33,457	40,426		(16,956)	12,111	69,050		283
Beginning Balance at Jun. 30, 2021	69,423		0	12	33,440	39,318		(15,941)	12,309	69,138		285
Preferred stock redemption premium	0
Treasury stock acquired in connection with share repurchases	(1,015)							(1,015)		(1,015)
Stock-based compensation	17				17					17
Dividends on preferred stock	(63)					(63)				(63)
Dividends on common stock	(413)					(413)				(413)
Change in equity of noncontrolling interests	(8)									0		(8)
Net income (loss)	1,589					1,584				1,584		5
Other comprehensive income (loss), net of income tax	$ (197)								(198)	(198)		1
Dividend Per Share	$ 0.480
Ending Balance at Sep. 30, 2021	$ 69,333		$ 0	$ 12	$ 33,457	$ 40,426		$ (16,956)	$ 12,111	$ 69,050		$ 283