Investments (Details 15) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 8,674
Fixed maturity securities on which noncredit OTTI losses have been recognized	56
Unrealized investment gains (losses) during the year	529
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	542
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(6)
DAC and VOBA	(20)
Policyholder dividend obligation	219
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(19)
Deferred income tax benefit (expense)	(456)
Net unrealized investment gains (losses)	9,519
Net unrealized investment gains (losses) attributable to noncontrolling interests	0
Balance, end of period	9,519
Changes in net unrealized investment gains (losses)	845
Changes in net unrealized investment gains (losses) attributable to noncontrolling interests	0
Changes in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ 845