Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 773,253	$ 795,146
U.S.
Segment Reporting Information [Line Items]
Total assets	283,698	291,483
Asia
Segment Reporting Information [Line Items]
Total assets	170,851	173,884
Latin America
Segment Reporting Information [Line Items]
Total assets	66,728	75,047
EMEA
Segment Reporting Information [Line Items]
Total assets	28,084	28,372
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	181,609	184,566
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 42,283	$ 41,794