Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock at Cost	Treasury Stock at Cost Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Total MetLife, Inc.'s Stockholders' Equity	Total MetLife, Inc.'s Stockholders' Equity Cumulative Effect, Period of Adoption, Adjustment	Total MetLife, Inc.'s Stockholders' Equity Cumulative Effect, Period of Adoption, Adjusted Balance	Noncontrolling Interests	Noncontrolling Interests Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning Balance at Dec. 31, 2018	$ 52,958	$ 95	$ 53,053	$ 0	$ 0	$ 12	$ 12	$ 32,474	$ 32,474	$ 28,926	$ 74	$ 29,000	$ (10,393)	$ (10,393)	$ 1,722	$ 21	$ 1,743	$ 52,741	$ 95	$ 52,836	$ 217	$ 217
Preferred stock issuance	0
Treasury stock acquired in connection with share repurchases	(500)												(500)					(500)
Stock-based compensation	61							61										61
Dividends on preferred stock	(32)									(32)								(32)
Dividends on common stock	(405)									(405)								(405)
Change in equity of noncontrolling interests	6																	0			6
Net income (loss)	1,385									1,381								1,381			4
Other comprehensive income (loss), net of income tax	5,170														5,168			5,168			2
Ending Balance at Mar. 31, 2019	58,738			0		12		32,535		29,944			(10,893)		6,911			58,509			229
Beginning Balance at Dec. 31, 2019	66,382	$ (121)	$ 66,261	0	$ 0	12	$ 12	32,680	$ 32,680	33,078	$ (121)	$ 32,957	(12,678)	$ (12,678)	13,052		$ 13,052	66,144	$ (121)	$ 66,023	238	$ 238
Preferred stock issuance	972							972										972
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)
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