Segment Information (Earnings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues
Premiums	$ 49,397	$ 42,009	$ 42,034
Universal life and investment-type product policy fees	5,585	5,756	5,603
Net investment income	15,916	21,395	17,117
Other revenues	2,634	2,619	1,849
Net investment gains (losses)	(1,262)	1,529	(110)
Net derivative gains (losses)	(2,372)	(2,228)	1,349
Total revenues	69,898	71,080	67,842
Expenses
Policyholder benefits and claims and policyholder dividends	51,313	44,830	42,551
Interest credited to policyholder account balances	3,692	5,538	5,214
Capitalization of DAC	(2,558)	(2,718)	(3,013)
Amortization of DAC and VOBA	1,931	2,555	3,160
Amortization of negative VOBA	(41)	(34)	(45)
Interest expense on debt	938	920	913
Other expenses	11,764	11,863	12,135
Total expenses	67,039	62,954	60,915
Provision for income tax expense (benefit)	301	1,551	1,509
Net income (loss)	2,558	6,575	5,418
U.S.
Expenses
Amortization of DAC and VOBA	59	158	471
Asia
Expenses
Amortization of DAC and VOBA	1,042	1,404	1,468
Latin America
Expenses
Amortization of DAC and VOBA	339	285	276
EMEA
Expenses
Amortization of DAC and VOBA	340	382	452
MetLife Holdings
Expenses
Amortization of DAC and VOBA	142	317	485
Corporate & Other
Expenses
Amortization of DAC and VOBA	9	9	8
Operating Segments
Revenues
Premiums	49,356	41,027	41,982
Universal life and investment-type product policy fees	5,532	5,561	5,465
Net investment income	18,189	21,280	17,328
Other revenues	2,471	2,376	1,690
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	75,548	70,244	66,465
Expenses
Policyholder benefits and claims and policyholder dividends	51,366	43,651	41,859
Interest credited to policyholder account balances	5,011	4,592	4,673
Capitalization of DAC	(2,547)	(2,599)	(3,008)
Amortization of DAC and VOBA	2,037	2,336	2,994
Amortization of negative VOBA	(41)	(34)	(45)
Interest expense on debt	938	919	913
Other expenses	11,501	11,299	11,872
Total expenses	68,265	60,164	59,258
Provision for income tax expense (benefit)	1,553	1,931	1,382
Adjusted earnings	5,730	8,149	5,825
Operating Segments | U.S.
Revenues
Premiums	35,548	26,358	27,265
Universal life and investment-type product policy fees	1,158	1,140	1,070
Net investment income	7,340	8,048	6,903
Other revenues	1,756	1,538	957
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	45,802	37,084	36,195
Expenses
Policyholder benefits and claims and policyholder dividends	36,273	27,957	26,309
Interest credited to policyholder account balances	1,789	1,422	1,622
Capitalization of DAC	(77)	(65)	(453)
Amortization of DAC and VOBA	59	60	471
Amortization of negative VOBA	0	0	0
Interest expense on debt	9	7	7
Other expenses	3,962	3,632	4,162
Total expenses	42,015	33,013	32,118
Provision for income tax expense (benefit)	791	850	853
Adjusted earnings	2,996	3,221	3,224
Operating Segments | Asia
Revenues
Premiums	5,568	6,421	6,571
Universal life and investment-type product policy fees	1,840	1,814	1,892
Net investment income	3,909	5,052	3,938
Other revenues	90	73	61
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	11,407	13,360	12,462
Expenses
Policyholder benefits and claims and policyholder dividends	4,752	5,008	5,213
Interest credited to policyholder account balances	2,003	1,995	1,834
Capitalization of DAC	(1,524)	(1,607)	(1,652)
Amortization of DAC and VOBA	1,105	1,369	1,415
Amortization of negative VOBA	(36)	(27)	(37)
Interest expense on debt	0	0	0
Other expenses	3,153	3,388	3,481
Total expenses	9,453	10,126	10,254
Provision for income tax expense (benefit)	576	936	643
Adjusted earnings	1,378	2,298	1,565
Operating Segments | Latin America
Revenues
Premiums	3,226	2,609	2,265
Universal life and investment-type product policy fees	1,175	1,109	994
Net investment income	1,593	1,271	992
Other revenues	39	41	38
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	6,033	5,030	4,289
Expenses
Policyholder benefits and claims and policyholder dividends	3,301	3,143	2,406
Interest credited to policyholder account balances	335	249	240
Capitalization of DAC	(499)	(414)	(362)
Amortization of DAC and VOBA	339	285	276
Amortization of negative VOBA	0	0	0
Interest expense on debt	12	5	4
Other expenses	1,553	1,401	1,318
Total expenses	5,041	4,669	3,882
Provision for income tax expense (benefit)	231	70	127
Adjusted earnings	761	291	280
Operating Segments | EMEA
Revenues
Premiums	1,964	2,271	2,259
Universal life and investment-type product policy fees	300	395	433
Net investment income	160	215	269
Other revenues	35	47	52
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	2,459	2,928	3,013
Expenses
Policyholder benefits and claims and policyholder dividends	990	1,241	1,196
Interest credited to policyholder account balances	71	86	109
Capitalization of DAC	(411)	(469)	(491)
Amortization of DAC and VOBA	333	356	454
Amortization of negative VOBA	(5)	(7)	(8)
Interest expense on debt	0	0	1
Other expenses	1,171	1,324	1,344
Total expenses	2,149	2,531	2,605
Provision for income tax expense (benefit)	64	96	81
Adjusted earnings	246	301	327
Operating Segments | MetLife Holdings
Revenues
Premiums	3,066	3,333	3,600
Universal life and investment-type product policy fees	1,057	1,101	1,073
Net investment income	4,971	6,450	5,184
Other revenues	155	257	238
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	9,249	11,141	10,095
Expenses
Policyholder benefits and claims and policyholder dividends	6,056	6,268	6,738
Interest credited to policyholder account balances	813	840	868
Capitalization of DAC	(28)	(33)	(39)
Amortization of DAC and VOBA	192	257	370
Amortization of negative VOBA	0	0	0
Interest expense on debt	8	5	6
Other expenses	953	992	942
Total expenses	7,994	8,329	8,885
Provision for income tax expense (benefit)	247	570	234
Adjusted earnings	1,008	2,242	976
Operating Segments | Corporate & Other
Revenues
Premiums	(16)	35	22
Universal life and investment-type product policy fees	2	2	3
Net investment income	216	244	42
Other revenues	396	420	344
Net investment gains (losses)	0	0	0
Net derivative gains (losses)	0	0	0
Total revenues	598	701	411
Expenses
Policyholder benefits and claims and policyholder dividends	(6)	34	(3)
Interest credited to policyholder account balances	0	0	0
Capitalization of DAC	(8)	(11)	(11)
Amortization of DAC and VOBA	9	9	8
Amortization of negative VOBA	0	0	0
Interest expense on debt	909	902	895
Other expenses	709	562	625
Total expenses	1,613	1,496	1,514
Provision for income tax expense (benefit)	(356)	(591)	(556)
Adjusted earnings	(659)	(204)	(547)
Significant Reconciling Items
Revenues
Premiums	41	982	52
Universal life and investment-type product policy fees	53	195	138
Net investment income	(2,273)	115	(211)
Other revenues	163	243	159
Net investment gains (losses)	(1,262)	1,529	(110)
Net derivative gains (losses)	(2,372)	(2,228)	1,349
Total revenues	(5,650)	836	1,377
Expenses
Policyholder benefits and claims and policyholder dividends	(53)	1,179	692
Interest credited to policyholder account balances	(1,319)	946	541
Capitalization of DAC	(11)	(119)	(5)
Amortization of DAC and VOBA	(106)	219	166
Amortization of negative VOBA	0	0	0
Interest expense on debt	0	1	0
Other expenses	263	564	263
Total expenses	(1,226)	2,790	1,657
Provision for income tax expense (benefit)	$ (1,252)	$ (380)	$ 127