Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total assets	$ 713,188	$ 687,538
U.S.
Segment Reporting Information [Line Items]
Total assets	257,461	248,174
Asia
Segment Reporting Information [Line Items]
Total assets	152,264	146,278
Latin America
Segment Reporting Information [Line Items]
Total assets	74,329	70,417
EMEA
Segment Reporting Information [Line Items]
Total assets	27,834	27,829
MetLife Holdings
Segment Reporting Information [Line Items]
Total assets	171,267	166,872
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 30,033	$ 27,968