Earnings Per Common Share (Details) (USD $) In Millions, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Weighted Average Shares:
Weighted average common stock outstanding for basic earnings per common share	1,060,199,513	875,782,191	1,059,253,798	840,375,518
Incremental common shares from assumed:
Stock purchase contracts underlying common equity units	0	0	2,188,593	0
Exercise or issuance of stock-based awards	6,001,186	7,317,973	7,221,794	6,950,540
Weighted average common stock outstanding for diluted earnings per common share	1,066,200,699	883,100,164	1,068,664,185	847,326,058
Income (Loss) from Continuing Operations:
Income (loss) from continuing operations, net of income tax	$ 3,572	$ 317	$ 5,825	$ 2,681
Less: Income (loss) from continuing operations, net of income tax, attributable to noncontrolling interests	(6)	4	(6)	(7)
Less: Preferred stock dividends	30	30	91	91
Preferred stock redemption premium	0	0	146	0
Income (loss) from continuing operations, net of income tax, available to MetLife, Inc.'s common shareholders	3,548	283	5,594	2,597
Basic	$ 3.35	$ 0.33	$ 5.29	$ 3.09
Diluted	$ 3.33	$ 0.32	$ 5.24	$ 3.07
Income (Loss) from Discontinued Operations:
Income (loss) from discontinued operations, net of income tax	4	3	(6)	20
Less: Income (loss) from discontinued operations, net of income tax, attributable to noncontrolling interests	0	0	0	0
Income (loss) from discontinued operations, net of income tax, available to MetLife, Inc.'s common shareholders	4	3	(6)	20
Basic	$ 0.00	$ 0	$ (0.01)	$ 0.02
Diluted	$ 0.00	$ 0	$ (0.01)	$ 0.02
Net Income (Loss):
Net income (loss)	3,576	320	5,819	2,701
Less: Net income (loss) attributable to noncontrolling interests	(6)	4	(6)	(7)
Less: Preferred stock dividends	30	30	91	91
Preferred stock redemption premium	0	0	146	0
Net income (loss) available to MetLife, Inc.'s common shareholders	$ 3,552	$ 286	$ 5,588	$ 2,617
Basic	$ 3.35	$ 0.33	$ 5.28	$ 3.11
Diluted	$ 3.33	$ 0.32	$ 5.23	$ 3.09