Earnings Per Common Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Weighted Average Shares:
Weighted average common stock outstanding for basic earnings per common share	1,064,252,898	1,058,517,978
Incremental common shares from assumed:
Stock purchase contracts underlying common equity units	0	2,550,138
Exercise or issuance of stock-based awards	0	8,455,420
Weighted average common stock outstanding for diluted earnings per common share	1,064,252,898	1,069,523,536
Income (Loss) from Continuing Operations:
Income (loss) from continuing operations, net of income tax	$ (134)	$ 924
Less: Income (loss) from continuing operations, net of income tax, attributable to noncontrolling interests	24	7
Less: Preferred stock dividends	30	30
Preferred stock redemption premium	0	146
Income (loss) from continuing operations, net of income tax, available to MetLife, Inc.'s common shareholders	(188)	741
Basic	$ (0.17)	$ 0.70
Diluted	$ (0.17)	$ 0.70
Income (Loss) from Discontinued Operations:
Income (loss) from discontinued operations, net of income tax	14	(40)
Less: Income (loss) from discontinued operations, net of income tax, attributable to noncontrolling interests	0	0
Income (loss) from discontinued operations, net of income tax, available to MetLife, Inc.'s common shareholders	14	(40)
Basic	$ 0.01	$ (0.04)
Diluted	$ 0.01	$ (0.04)
Net Income (Loss):
Net income (loss)	(120)	884
Less: Net income (loss) attributable to noncontrolling interests	24	7
Less: Preferred stock dividends	30	30
Preferred stock redemption premium	0	146
Net income (loss) available to MetLife, Inc.'s common shareholders	$ (174)	$ 701
Basic	$ (0.16)	$ 0.66
Diluted	$ (0.16)	$ 0.66
Earnings Per Common Share (Textuals) [Abstract]
Shares excluded from the calculation of diluted earnings per common share as the assumed exercise or issuance are anti-dilutive	6,627,984