Investments (Changes in Net Unrealized Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 14,419
Fixed maturity securities on which noncredit OTTI losses have been recognized	84
Unrealized investment gains (losses) during the year	(12,434)
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	3,837
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(8)
DAC and VOBA	877
Policyholder dividend obligation	1,555
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(27)
Deferred income tax benefit (expense)	2,153
Net unrealized investment gains (losses)	10,456
Net unrealized investment gains (losses) attributable to noncontrolling interests	(13)
Balance, end of period	10,443
Changes in net unrealized investment gains (losses)	(3,963)
Changes in net unrealized investment gains (losses) attributable to noncontrolling interests	(13)
Changes in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ (3,976)