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	59				59					59
Dividends on preferred stock	(32)					(32)				(32)
Dividends on common stock	(404)					(404)				(404)
Preferred stock issuance	$ 972				972					972
Dividend Per Share	$ 0.440
Net income (loss)	$ 4,401					4,398				4,398		3
Other comprehensive income (loss), net of income tax	(294)								(295)	(295)		1
Ending Balance at Mar. 31, 2020	70,463		0	12	33,711	36,919		(13,178)	12,757	70,221		242
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)
Dividends on preferred stock	(109)
Preferred stock issuance	972
Preferred stock redemption premium	0
Net income (loss)	4,551
Ending Balance at Jun. 30, 2020	75,940		0	12	33,728	36,568		(13,178)	18,563	75,693		247
Beginning Balance at Mar. 31, 2020	70,463		0	12	33,711	36,919		(13,178)	12,757	70,221		242
Stock-based compensation	17				17					17
Dividends on preferred stock	(77)					(77)				(77)
Dividends on common stock	(419)					(419)				(419)
Preferred stock redemption premium	$ 0
Dividend Per Share	$ 0.460
Change in equity of noncontrolling interests	$ (1)									0		(1)
Net income (loss)	150					145				145		5
Other comprehensive income (loss), net of income tax	5,807								5,806	5,806		1
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, 2020	74,817		0	12	33,812	36,491		(13,829)	18,072	74,558		259
Treasury stock acquired in connection with share repurchases	(999)							(999)		(999)
Stock-based compensation	98				98					98
Dividends on preferred stock	(68)					(68)				(68)
Dividends on common stock	$ (408)					(408)				(408)
Dividend Per Share	$ 0.460
Change in equity of noncontrolling interests	$ 9									0		9
Net income (loss)	363					358				358		5
Other comprehensive income (loss), net of income tax	(7,675)								(7,675)	(7,675)		0
Ending Balance at Mar. 31, 2021	66,137		0	12	33,910	36,373		(14,828)	10,397	65,864		273
Beginning Balance at Dec. 31, 2020	74,817		0	12	33,812	36,491		(13,829)	18,072	74,558		259
Treasury stock acquired in connection with share repurchases	(2,100)
Dividends on preferred stock	(103)
Preferred stock issuance	0
Preferred stock redemption premium	(6)
Net income (loss)	3,775
Ending Balance at Jun. 30, 2021	69,423		0	12	33,440	39,318		(15,941)	12,309	69,138		285
Beginning Balance at Mar. 31, 2021	66,137		0	12	33,910	36,373		(14,828)	10,397	65,864		273
Treasury stock acquired in connection with share repurchases	(1,113)							(1,113)		(1,113)
Stock-based compensation	24				24					24
Dividends on preferred stock	(35)					(35)				(35)
Dividends on common stock	(421)					(421)				(421)
Redemption of preferred stock	(494)				(494)					(494)
Preferred stock redemption premium	$ (6)					(6)				(6)
Dividend Per Share	$ 0.480
Change in equity of noncontrolling interests	$ 6									0		6
Net income (loss)	3,412					3,407				3,407		5
Other comprehensive income (loss), net of income tax	1,913								1,912	1,912		1
Ending Balance at Jun. 30, 2021	$ 69,423		$ 0	$ 12	$ 33,440	$ 39,318		$ (15,941)	$ 12,309	$ 69,138		$ 285