Investments (Net Unrealized Investment Gains Losses) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Components of net unrealized investment gains (losses) included in accumulated other comprehensive loss
Fixed maturity securities	$ 25,818	$ 20,300
Fixed maturity securities with noncredit OTTI losses included in AOCI	37	8
Total fixed maturity securities	25,855	20,308
Equity securities	522	485
Derivatives	2,468	2,923
Other	169	23
Subtotal	29,014	23,739
Future policy benefits	(2,046)	(1,114)
DAC and VOBA related to noncredit OTTI losses recognized in AOCI	(3)	(3)
DAC, VOBA and DSI	(1,750)	(1,430)
Policyholder dividend obligation	(2,237)	(1,931)
Subtotal	(6,036)	(4,478)
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in AOCI	(11)	(1)
Deferred income tax benefit (expense)	(7,923)	(6,623)
Net unrealized investment gains (losses)	15,044	12,637
Net unrealized investment gains (losses) attributable to noncontrolling interests	(6)	(6)
Net unrealized investment gains (losses) attributable to MetLife, Inc.	$ 15,038	$ 12,631