Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 769,814	$ 795,146
U.S.
Segment Reporting Information [Line Items]
Total assets	286,236	291,483
Asia
Segment Reporting Information [Line Items]
Total assets	167,686	173,884
Latin America
Segment Reporting Information [Line Items]
Total assets	72,691	75,047
EMEA
Segment Reporting Information [Line Items]
Total assets	27,126	28,372
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	178,030	184,566
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 38,045	$ 41,794