Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 706,333	$ 719,892
U.S.
Segment Reporting Information [Line Items]
Total assets	256,668	255,428
Asia
Segment Reporting Information [Line Items]
Total assets	141,653	136,928
Latin America
Segment Reporting Information [Line Items]
Total assets	73,214	79,670
EMEA
Segment Reporting Information [Line Items]
Total assets	29,353	30,500
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	174,470	183,160
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 30,975	$ 34,206