Investments (Changes in Net Unrealized Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 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	38
Unrealized investment gains (losses) during the year	6,263
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	(354)
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(1)
DAC and VOBA	(322)
Policyholder dividend obligation	(692)
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(13)
Deferred income tax benefit (expense)	(1,667)
Net unrealized investment gains (losses)	11,666
Net unrealized investment gains (losses) attributable to noncontrolling interests	14
Balance, end of period	11,680
Changes in net unrealized investment gains (losses)	3,252
Changes in net unrealized investment gains (losses) attributable to noncontrolling interests	14
Changes in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ 3,266