Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill Rollforward and by Segment
Goodwill - beginning of period	$ 9,988	$ 10,102	$ 10,270
Accumulated impairment	(680)	(680)	(680)
Total goodwill, net - beginning of period	9,308	9,422	9,590
Acquisitions	932	19
Disposition		(71)
Effect of foreign currency translation and other	200	(62)	(168)
Goodwill - end of period	10,792	9,988	10,102
Accumulated impairment	(680)	(680)	(680)
Total goodwill, net - end of period	10,112	9,308	9,422
Metropolitan Property And Casualty Insurance Company [Member]
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	328
Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	328
U.S.
Goodwill Rollforward and by Segment
Goodwill - beginning of period	1,466	1,451	1,451
Accumulated impairment	0	0	0
Total goodwill, net - beginning of period	1,466	1,451	1,451
Acquisitions	932	15
Disposition		0
Effect of foreign currency translation and other	0	0	0
Goodwill - end of period	2,070	1,466	1,451
Accumulated impairment	0	0	0
Total goodwill, net - end of period	2,070	1,466	1,451
U.S. | Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	328
Asia
Goodwill Rollforward and by Segment
Goodwill - beginning of period	4,636	4,690	4,673
Accumulated impairment	0	0	0
Total goodwill, net - beginning of period	4,636	4,690	4,673
Acquisitions	0	4
Disposition		(71)
Effect of foreign currency translation and other	127	13	17
Goodwill - end of period	4,763	4,636	4,690
Accumulated impairment	0	0	0
Total goodwill, net - end of period	4,763	4,636	4,690
Asia | Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	0
Latin America
Goodwill Rollforward and by Segment
Goodwill - beginning of period	1,099	1,172	1,306
Accumulated impairment	0	0	0
Total goodwill, net - beginning of period	1,099	1,172	1,306
Acquisitions	0	0
Disposition		0
Effect of foreign currency translation and other	44	(73)	(134)
Goodwill - end of period	1,143	1,099	1,172
Accumulated impairment	0	0	0
Total goodwill, net - end of period	1,143	1,099	1,172
Latin America | Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	0
EMEA
Goodwill Rollforward and by Segment
Goodwill - beginning of period	1,117	1,119	1,170
Accumulated impairment	0	0	0
Total goodwill, net - beginning of period	1,117	1,119	1,170
Acquisitions	0	0
Disposition		0
Effect of foreign currency translation and other	29	(2)	(51)
Goodwill - end of period	1,146	1,117	1,119
Accumulated impairment	0	0	0
Total goodwill, net - end of period	1,146	1,117	1,119
EMEA | Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	0
MetLife Holdings
Goodwill Rollforward and by Segment
Goodwill - beginning of period	1,567	1,567	1,567
Accumulated impairment	(680)	(680)	(680)
Total goodwill, net - beginning of period	887	887	887
Acquisitions	0	0
Disposition		0
Effect of foreign currency translation and other	0	0	0
Goodwill - end of period	1,567	1,567	1,567
Accumulated impairment	(680)	(680)	(680)
Total goodwill, net - end of period	887	887	887
MetLife Holdings | Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	0
Corporate & Other
Goodwill Rollforward and by Segment
Goodwill - beginning of period	103	103	103
Accumulated impairment	0	0	0
Total goodwill, net - beginning of period	103	103	103
Acquisitions	0	0
Disposition		0
Effect of foreign currency translation and other	0	0	0
Goodwill - end of period	103	103	103
Accumulated impairment	0	0	0
Total goodwill, net - end of period	103	103	103
Corporate & Other | Goodwill
Goodwill Rollforward and by Segment
Disposal Group, Including Discontinued Operation, Goodwill	0
JAPAN
Goodwill Rollforward and by Segment
Total goodwill, net - beginning of period	4,500	4,500
Total goodwill, net - end of period	$ 4,600	$ 4,500	$ 4,500