Investments (Changes in Net Unrealized Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 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	120
Unrealized investment gains (losses) during the year	(16,042)
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	4,950
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(12)
DAC and VOBA	1,179
Policyholder dividend obligation	1,815
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(38)
Deferred income tax benefit (expense)	2,674
Net unrealized investment gains (losses)	9,065
Net unrealized investment gains (losses) attributable to noncontrolling interests	35
Balance, end of period	9,100
Changes in net unrealized investment gains (losses)	(5,354)
Changes in net unrealized investment gains (losses) attributable to noncontrolling interests	35
Changes in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ (5,319)