Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 737,741	$ 740,463
U.S.
Segment Reporting Information [Line Items]
Total assets	273,341	266,174
Asia
Segment Reporting Information [Line Items]
Total assets	160,442	161,018
Latin America
Segment Reporting Information [Line Items]
Total assets	61,526	75,069
EMEA
Segment Reporting Information [Line Items]
Total assets	24,365	27,281
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	172,347	175,199
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 45,720	$ 35,722