Earnings Per Common Share (Details) (USD $) In Millions, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Weighted Average Shares:
Weighted average common stock outstanding for basic earnings per common share	1,059,751,486	822,905,671	1,058,795,981	822,407,969
Incremental common shares from assumed:
Stock purchase contracts underlying common equity units	4,015,640	0	3,282,889	0
Exercise or issuance of stock-based awards	7,208,779	7,567,202	7,832,099	6,766,823
Weighted average common stock outstanding for diluted earnings per common share	1,070,975,905	830,472,873	1,069,910,969	829,174,792
Income (Loss) from Continuing Operations:
Income (loss) from continuing operations, net of income tax	$ 1,201	$ 1,536	$ 2,255	$ 2,364
Less: Income (loss) from continuing operations, net of income tax, attributable to noncontrolling interests	(7)	(10)	0	(11)
Less: Preferred stock dividends	31	31	61	61
Preferred stock redemption premium	0	0	146	0
Income (loss) from continuing operations, net of income tax, available to MetLife, Inc.'s common shareholders	1,177	1,515	2,048	2,314
Basic	$ 1.11	$ 1.84	$ 1.93	$ 2.81
Diluted	$ 1.10	$ 1.83	$ 1.91	$ 2.79
Income (Loss) from Discontinued Operations:
Income (loss) from discontinued operations, net of income tax	29	11	(12)	17
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	29	11	(12)	17
Basic	$ 0.03	$ 0.01	$ (0.01)	$ 0.02
Diluted	$ 0.03	$ 0.01	$ (0.01)	$ 0.02
Net Income (Loss):
Net income (loss)	1,230	1,547	2,243	2,381
Less: Net income (loss) attributable to noncontrolling interests	(7)	(10)	0	(11)
Less: Preferred stock dividends	31	31	61	61
Preferred stock redemption premium	0	0	146	0
Net income (loss) available to MetLife, Inc.'s common shareholders	$ 1,206	$ 1,526	$ 2,036	$ 2,331
Basic	$ 1.14	$ 1.85	$ 1.92	$ 2.83
Diluted	$ 1.13	$ 1.84	$ 1.90	$ 2.81