Earnings Per Common Share (Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Weighted Average Shares
Weighted average common stock outstanding for basic earnings per common share	1,100,836,608	1,125,703,588
Incremental common shares from assumed:
Exercise or issuance of stock-based awards	7,785,089	10,057,530
Weighted average common stock outstanding for diluted earnings per common share	1,108,621,697	1,135,761,118
Net Income (Loss)
Net income (loss)	$ 2,203	$ 2,163
Less: Net income (loss) attributable to noncontrolling interests	2	5
Less: Preferred stock dividends	6	30
Net income (loss) available to MetLife, Inc.’s common shareholders	$ 2,195	$ 2,128
Basic	$ 1.99	$ 1.89
Diluted	$ 1.98	$ 1.87