Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (DAC and VOBA by Segment) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
DAC and VOBA	$ 16,389	$ 17,833	$ 18,895
U.S.
Segment Reporting Information [Line Items]
DAC and VOBA	434	649
Asia
Segment Reporting Information [Line Items]
DAC and VOBA	9,333	9,764
Latin America
Segment Reporting Information [Line Items]
DAC and VOBA	2,092	2,038
EMEA
Segment Reporting Information [Line Items]
DAC and VOBA	1,787	1,701
MetLife Holdings
Segment Reporting Information [Line Items]
DAC and VOBA	2,712	3,656
Corporate & Other
Segment Reporting Information [Line Items]
DAC and VOBA	$ 31	$ 25