Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Separate account assets	$ 175,556	$ 205,001
Separate account liabilities	175,556	205,001
Total assets	687,538	719,892
U.S.
Segment Reporting Information [Line Items]
Separate account assets	71,436	81,243
Separate account liabilities	71,436	81,243
Total assets	248,174	255,428
Asia
Segment Reporting Information [Line Items]
Separate account assets	8,849	10,032
Separate account liabilities	8,849	10,032
Total assets	146,278	136,928
Latin America
Segment Reporting Information [Line Items]
Separate account assets	47,757	56,218
Separate account liabilities	47,757	56,218
Total assets	70,417	79,670
EMEA
Segment Reporting Information [Line Items]
Separate account assets	5,306	5,975
Separate account liabilities	5,306	5,975
Total assets	27,829	30,500
MetLife Holdings
Segment Reporting Information [Line Items]
Separate account assets	42,208	51,533
Separate account liabilities	42,208	51,533
Total assets	166,872	183,160
Corporate & Other
Segment Reporting Information [Line Items]
Separate account assets	0	0
Separate account liabilities	0	0
Total assets	$ 27,968	$ 34,206