Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles - Transition Table (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	$ 18,388	$ 17,644	$ 17,415	$ 17,451	$ 13,446
Balance at January 1, 2021	18,388	17,644	17,415	17,451	13,446
Present Value of Future Insurance Profits, Net	1,763	2,009	2,391	2,966	2,943
Balance at January 1, 2021	1,763	2,009	2,391	2,966	2,943
Balance at December 31, 2020					2,113
Balance at January 1, 2021					2,113
Balance at December 31, 2020	427	473	557	666	738
Balance at January 1, 2021	427	473	557	666	738
Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				17,451
Removal of related amounts in AOCI				3,980
Other adjustments upon adoption of the LDTI standard				25
Balance at January 1, 2021				17,451
Present Value of Future Insurance Profits, Net				2,966
Removal of related amounts in AOCI				27
Other adjustments upon adoption of the LDTI standard				(4)
Balance at January 1, 2021				2,966
Balance at December 31, 2020				3,163
Removal of related amounts in AOCI				1,043
Other adjustments upon adoption of the LDTI standard				7
Balance at January 1, 2021				3,163
Reclassification of carrying amounts of contracts and contract features that are market risk benefits				(72)
Group Benefits
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	258	264	272	279	279
Balance at January 1, 2021	258	264	272	279	279
Present Value of Future Insurance Profits, Net	0	0	0	0	0
Balance at January 1, 2021	0	0	0	0	0
Balance at December 31, 2020					0
Balance at January 1, 2021					0
Group Benefits | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				279
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				279
Present Value of Future Insurance Profits, Net				0
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				0
Balance at December 31, 2020				0
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				0
Retirement and Income Solutions
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	397	267	191	130	130
Balance at January 1, 2021	397	267	191	130	130
Present Value of Future Insurance Profits, Net	16	19	22	25	25
Balance at January 1, 2021	16	19	22	25	25
Balance at December 31, 2020					42
Balance at January 1, 2021					42
Retirement and Income Solutions | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				130
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				130
Present Value of Future Insurance Profits, Net				25
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				25
Balance at December 31, 2020				42
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				42
Asia
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	10,864	10,270	10,058	9,741	7,432
Balance at January 1, 2021	10,864	10,270	10,058	9,741	7,432
Present Value of Future Insurance Profits, Net	1,119	1,290	1,593	1,915	1,901
Balance at January 1, 2021	1,119	1,290	1,593	1,915	1,901
Balance at December 31, 2020					587
Balance at January 1, 2021					587
Asia | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				9,741
Removal of related amounts in AOCI				2,309
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				9,741
Present Value of Future Insurance Profits, Net				1,915
Removal of related amounts in AOCI				14
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				1,915
Balance at December 31, 2020				1,616
Removal of related amounts in AOCI				1,029
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				1,616
Latin America
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	1,950	1,542	1,361	1,394	1,344
Balance at January 1, 2021	1,950	1,542	1,361	1,394	1,344
Present Value of Future Insurance Profits, Net	497	545	591	756	748
Balance at January 1, 2021	497	545	591	756	748
Balance at December 31, 2020					740
Balance at January 1, 2021					740
Latin America | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				1,394
Removal of related amounts in AOCI				50
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				1,394
Present Value of Future Insurance Profits, Net				756
Removal of related amounts in AOCI				8
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				756
Balance at December 31, 2020				835
Removal of related amounts in AOCI				95
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				835
EMEA
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	1,618	1,480	1,472	1,565	1,551
Balance at January 1, 2021	1,618	1,480	1,472	1,565	1,551
Present Value of Future Insurance Profits, Net	113	127	154	232	236
Balance at January 1, 2021	113	127	154	232	236
Balance at December 31, 2020					556
Balance at January 1, 2021					556
EMEA | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				1,565
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				14
Balance at January 1, 2021				1,565
Present Value of Future Insurance Profits, Net				232
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				(4)
Balance at January 1, 2021				232
Balance at December 31, 2020				482
Removal of related amounts in AOCI				(81)
Other adjustments upon adoption of the LDTI standard				7
Balance at January 1, 2021				482
MetLife Holdings
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	3,271	3,791	4,029	4,311	2,679
Balance at January 1, 2021	3,271	3,791	4,029	4,311	2,679
Present Value of Future Insurance Profits, Net	18	28	31	38	33
Balance at January 1, 2021	18	28	31	38	33
Balance at December 31, 2020					188
Balance at January 1, 2021					188
MetLife Holdings | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				4,311
Removal of related amounts in AOCI				1,621
Other adjustments upon adoption of the LDTI standard				11
Balance at January 1, 2021				4,311
Present Value of Future Insurance Profits, Net				38
Removal of related amounts in AOCI				5
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				38
Balance at December 31, 2020				188
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				188
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost	30	30	32	31	31
Balance at January 1, 2021	30	30	32	31	31
Present Value of Future Insurance Profits, Net	0	0	0	0	0
Balance at January 1, 2021	$ 0	$ 0	$ 0	0	0
Balance at December 31, 2020					0
Balance at January 1, 2021					$ 0
Corporate and Other [Member] | Accounting Standards Update 2018-12
Segment Reporting Information [Line Items]
Deferred Policy Acquisition Cost				31
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				31
Present Value of Future Insurance Profits, Net				0
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				0
Balance at December 31, 2020				0
Removal of related amounts in AOCI				0
Other adjustments upon adoption of the LDTI standard				0
Balance at January 1, 2021				$ 0