Earnings Per Common Share (Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Weighted Average Shares:
Weighted average common stock outstanding for basic earnings per common share	1,100,504,563	1,118,856,041	1,100,558,083	1,120,130,708
Incremental common shares from assumed:
Exercise or issuance of stock-based awards	8,749,753	11,085,040	8,445,077	10,575,611
Weighted average common stock outstanding for diluted earnings per common share	1,109,254,316	1,129,941,081	1,109,003,160	1,130,706,319
Net Income (Loss):
Net income (loss)	$ 573	$ 1,198	$ 2,890	$ 4,480
Less: Net income (loss) attributable to noncontrolling interests	(4)	(5)	2	4
Less: Preferred stock dividends	6	6	58	67
Preferred stock repurchase premium	0	0	0	42
Net income (loss) available to MetLife, Inc.’s common shareholders	$ 571	$ 1,197	$ 2,830	$ 4,367
Basic	$ 0.52	$ 1.07	$ 2.57	$ 3.90
Diluted	$ 0.51	$ 1.06	$ 2.55	$ 3.86