Earnings Per Common Share (Earnings Per Common Share) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Weighted Average Shares:
Weighted average common stock outstanding for basic earnings per common share	1,126,922,641	1,096,925,583
Incremental common shares from assumed:
Stock purchase contracts underlying common equity units	3,385,696	0
Exercise or issuance of stock-based awards	10,157,701	6,959,822
Weighted average common stock outstanding for diluted earnings per common share	1,140,466,038	1,103,885,405
Income (Loss) from Continuing Operations:
Income (loss) from continuing operations, net of income tax	$ 1,342	$ 995
Less: Income (loss) from continuing operations, net of income tax, attributable to noncontrolling interests	11	6
Less: Preferred stock dividends	30	30
Income (loss) from continuing operations, net of income tax, available to MetLife, Inc.'s common shareholders	1,301	959
Basic	$ 1.15	$ 0.87
Diluted	$ 1.14	$ 0.87
Income (Loss) from Discontinued Operations:
Income (loss) from discontinued operations, net of income tax	(3)	(3)
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	(3)	(3)
Basic	$ 0.00	$ 0.00
Diluted	$ 0.00	$ 0.00
Net Income (Loss):
Net income (loss)	1,339	992
Less: Net income (loss) attributable to noncontrolling interests	11	6
Less: Preferred stock dividends	30	30
Net income (loss) available to MetLife, Inc.'s common shareholders	$ 1,298	$ 956
Basic	$ 1.15	$ 0.87
Diluted	$ 1.14	$ 0.87