Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 461,123	$ 430,817
U.S.
Segment Reporting Information [Line Items]
Total assets	265,337	246,319
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	161,475	156,327
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 34,311	$ 28,171