Investments (Changes in Net Unrealized Investment Gains Losses) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2015 USD ($)
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 16,235
Fixed maturity securities on which noncredit OTTI losses have been recognized	62
Unrealized investment gains (losses) during the period	(8,102)
Unrealized investment gains (losses) relating to [Abstract]
Future policy benefits	1,577
DAC and VOBA related to noncredit OTTI losses recognized in AOCI	0
DAC, VOBA and DSI	495
Policyholder dividend obligation	827
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in AOCI	(22)
Deferred income tax benefit (expense)	1,782
Net unrealized investment gains (losses)	12,854
Net unrealized investment gains (losses) attributable to noncontrolling interests	9
Balance, end of period	12,863
Change in net unrealized investment gains (losses)	(3,381)
Change in net unrealized investment gains (losses) attributable to noncontrolling interests	9
Change in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ (3,372)