Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock at Cost	Accumulated Other Comprehensive Income (Loss)	Total MetLife, Inc.'s Stockholders' Equity	Noncontrolling Interests	Previously Reported	Previously Reported Preferred Stock	Previously Reported Common Stock	Previously Reported Additional Paid-in Capital	Previously Reported Retained Earnings	Previously Reported Treasury Stock at Cost	Previously Reported Accumulated Other Comprehensive Income (Loss)	Previously Reported Total MetLife, Inc.'s Stockholders' Equity	Previously Reported Noncontrolling Interests	Restatement Adjustment	Restatement Adjustment Retained Earnings	Restatement Adjustment Accumulated Other Comprehensive Income (Loss)	Restatement Adjustment Total MetLife, Inc.'s Stockholders' Equity
Beginning Balance at Dec. 31, 2016	$ 67,702	$ 0	$ 12	$ 30,944	$ 34,683	$ (3,474)	$ 5,366	$ 67,531	$ 171	$ 67,480	$ 0	$ 12	$ 30,944	$ 34,480	$ (3,474)	$ 5,347	$ 67,309	$ 171	$ 222	$ 203	$ 19	$ 222
Treasury stock acquired in connection with share repurchases	(1,810)					(1,810)		(1,810)
Stock-based compensation	77			77				77
Dividends on preferred stock	(52)				(52)			(52)
Dividends on common stock	(868)				(868)			(868)
Change in equity of noncontrolling interests	37							0	37
Net income (loss)	1,790				1,784			1,784	6
Other comprehensive income (loss), net of income tax	3,070						3,070	3,070	0							3,089					$ (19)
Ending Balance at Jun. 30, 2017	69,946	0	12	31,021	35,547	(5,284)	8,436	69,732	214	69,669									$ 277
Cumulative effects of changes in accounting principles, net of income tax (Note 1)	7				(905)		912	7
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	58,877	0	12	31,111	25,622	(6,401)	8,339	58,683	194
Beginning Balance at Dec. 31, 2017	58,870									$ 58,870	$ 0	$ 12	$ 31,111	$ 26,527	$ (6,401)	$ 7,427	$ 58,676	$ 194
Preferred stock issuance	1,274			1,274				1,274
Treasury stock acquired in connection with share repurchases	(2,156)					(2,156)		(2,156)
Stock-based compensation	69			69				69
Dividends on preferred stock	(52)				(52)			(52)
Dividends on common stock	(844)				(844)			(844)
Change in equity of noncontrolling interests	(3)							0	(3)
Net income (loss)	2,151				2,144			2,144	7
Other comprehensive income (loss), net of income tax	(5,484)						(5,485)	(5,485)	1
Ending Balance at Jun. 30, 2018	$ 53,832	$ 0	$ 12	$ 32,454	$ 26,870	$ (8,557)	$ 2,854	$ 53,633	$ 199