Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 761,664	$ 795,146
U.S.
Segment Reporting Information [Line Items]
Total assets	282,606	291,483
Asia
Segment Reporting Information [Line Items]
Total assets	169,699	173,884
Latin America
Segment Reporting Information [Line Items]
Total assets	60,592	75,047
EMEA
Segment Reporting Information [Line Items]
Total assets	27,523	28,372
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	180,239	184,566
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 41,005	$ 41,794