Investments (Changes in Net Unrealized Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 8,414
Fixed maturity securities on which noncredit OTTI losses have been recognized	113
Unrealized investment gains (losses) during the year	11,436
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	(617)
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(4)
DAC and VOBA	(676)
Policyholder dividend obligation	(1,054)
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(40)
Deferred income tax benefit (expense)	(2,879)
Net unrealized investment gains (losses)	14,693
Net unrealized investment gains (losses) attributable to noncontrolling interests	(4)
Balance, end of period	14,689
Changes in net unrealized investment gains (losses)	6,279
Changes in net unrealized investment gains (losses) attributable to noncontrolling interests	(4)
Changes in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ 6,275