Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (DAC and VOBA by Segment) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
DAC and VOBA	$ 18,419	$ 17,590	$ 17,430
U.S.
Segment Reporting Information [Line Items]
DAC and VOBA	614	616	615
Asia
Segment Reporting Information [Line Items]
DAC and VOBA	9,261	8,707	8,386
Latin America
Segment Reporting Information [Line Items]
DAC and VOBA	2,050	1,808	1,753
EMEA
Segment Reporting Information [Line Items]
DAC and VOBA	1,673	1,472	1,532
MetLife Holdings
Segment Reporting Information [Line Items]
DAC and VOBA	4,797	5,246	5,436
Corporate & Other
Segment Reporting Information [Line Items]
DAC and VOBA	$ 24	$ (259)	$ (292)