Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 712,584	$ 719,892
U.S.
Segment Reporting Information [Line Items]
Total assets	251,496	255,428
Asia
Segment Reporting Information [Line Items]
Total assets	143,458	136,928
Latin America
Segment Reporting Information [Line Items]
Total assets	78,638	79,670
EMEA
Segment Reporting Information [Line Items]
Total assets	30,546	30,500
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	175,817	183,160
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 32,629	$ 34,206