Segment Information (Earnings) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues
Premiums	$ 11,628	$ 11,678	$ 21,681	$ 21,267
Universal life and investment-type product policy fees	1,281	1,288	2,529	2,577
Net investment income	5,205	5,072	10,641	9,717
Other revenues	638	621	1,312	1,260
Net investment gains (losses)	(421)	(1,039)	(796)	(1,723)
Net derivative gains (losses)	(508)	(997)	(1,487)	(1,087)
Total revenues	17,823	16,623	33,880	32,011
Expenses
Policyholder benefits and claims and policyholder dividends	11,633	11,960	21,854	21,991
Policyholder liability remeasurement (gains) losses	(10)	(16)	(32)	(25)
Market risk benefit remeasurement (gains) losses	(182)	(817)	(876)	(629)
Interest credited to policyholder account balances	2,000	1,933	4,290	3,797
Capitalization of DAC	(683)	(729)	(1,423)	(1,447)
Amortization of DAC and VOBA	499	479	1,007	949
Amortization of negative VOBA	(6)	(6)	(12)	(13)
Interest expense on debt	257	256	521	511
Other expenses	3,113	3,133	6,304	6,190
Total expenses	16,621	16,193	31,633	31,324
Provision for income tax expense (benefit)	249	22	419	194
Net income (loss)	953	408	1,828	493
Operating Segments
Revenues
Premiums	11,628	11,678	21,681	21,267
Universal life and investment-type product policy fees	1,281	1,288	2,529	2,577
Net investment income	5,160	5,040	10,228	9,646
Other revenues	614	628	1,261	1,270
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	18,683	18,634	35,699	34,760
Expenses
Policyholder benefits and claims and policyholder dividends	11,560	11,930	21,834	21,891
Policyholder liability remeasurement (gains) losses	(10)	(16)	(32)	(25)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	1,781	1,642	3,508	3,184
Capitalization of DAC	(683)	(729)	(1,423)	(1,447)
Amortization of DAC and VOBA	499	479	1,007	949
Amortization of negative VOBA	(6)	(6)	(12)	(13)
Interest expense on debt	257	256	521	511
Other expenses	3,104	3,113	6,284	6,143
Total expenses	16,502	16,669	31,687	31,193
Provision for income tax expense (benefit)	519	441	949	793
Adjusted earnings	1,662	1,524	3,063	2,774
Segment Reconciling Items
Revenues
Premiums	0	0	0	0
Universal life and investment-type product policy fees	0	0	0	0
Net investment income	45	32	413	71
Other revenues	24	(7)	51	(10)
Net investment gains (losses)	(421)	(1,039)	(796)	(1,723)
Net derivative gains (losses)	(508)	(997)	(1,487)	(1,087)
Total revenues	(860)	(2,011)	(1,819)	(2,749)
Expenses
Policyholder benefits and claims and policyholder dividends	73	30	20	100
Policyholder liability remeasurement (gains) losses	0	0	0	0
Market risk benefit remeasurement (gains) losses	(182)	(817)	(876)	(629)
Interest credited to policyholder account balances	219	291	782	613
Capitalization of DAC	0	0	0	0
Amortization of DAC and VOBA	0	0	0	0
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	0	0	0	0
Other expenses	9	20	20	47
Total expenses	119	(476)	(54)	131
Provision for income tax expense (benefit)	(270)	(419)	(530)	(599)
Group Benefits
Expenses
Capitalization of DAC			(9)	(11)
Group Benefits | Operating Segments
Revenues
Premiums	5,599	5,427	11,310	10,878
Universal life and investment-type product policy fees	229	223	451	441
Net investment income	313	327	628	637
Other revenues	382	363	779	743
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	6,523	6,340	13,168	12,699
Expenses
Policyholder benefits and claims and policyholder dividends	4,780	4,866	10,016	9,860
Policyholder liability remeasurement (gains) losses	2	2	(1)	(2)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	48	48	96	94
Capitalization of DAC	(5)	(5)	(9)	(11)
Amortization of DAC and VOBA	7	7	13	13
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	1	1	1	1
Other expenses	1,016	950	2,019	1,882
Total expenses	5,849	5,869	12,135	11,837
Provision for income tax expense (benefit)	141	99	216	183
Adjusted earnings	533	372	817	679
RIS
Expenses
Capitalization of DAC			(107)	(95)
RIS | Operating Segments
Revenues
Premiums	2,448	2,681	3,123	3,182
Universal life and investment-type product policy fees	73	71	148	150
Net investment income	2,117	1,948	4,206	3,762
Other revenues	61	71	124	139
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	4,699	4,771	7,601	7,233
Expenses
Policyholder benefits and claims and policyholder dividends	3,248	3,441	4,719	4,666
Policyholder liability remeasurement (gains) losses	(23)	(11)	(22)	(40)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	838	702	1,634	1,348
Capitalization of DAC	(46)	(50)	(107)	(95)
Amortization of DAC and VOBA	16	12	31	23
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	3	4	7	7
Other expenses	145	146	317	292
Total expenses	4,181	4,244	6,579	6,201
Provision for income tax expense (benefit)	108	110	213	215
Adjusted earnings	410	417	809	817
Asia
Expenses
Capitalization of DAC			(696)	(798)
Asia | Operating Segments
Revenues
Premiums	1,216	1,310	2,513	2,687
Universal life and investment-type product policy fees	434	396	860	793
Net investment income	1,167	1,050	2,275	1,931
Other revenues	18	21	39	41
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	2,835	2,777	5,687	5,452
Expenses
Policyholder benefits and claims and policyholder dividends	988	1,057	2,055	2,187
Policyholder liability remeasurement (gains) losses	(4)	(27)	(36)	(16)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	657	570	1,304	1,106
Capitalization of DAC	(335)	(397)	(696)	(798)
Amortization of DAC and VOBA	207	190	417	383
Amortization of negative VOBA	(5)	(5)	(10)	(11)
Interest expense on debt	0	0	0	0
Other expenses	702	778	1,446	1,585
Total expenses	2,210	2,166	4,480	4,436
Provision for income tax expense (benefit)	176	180	335	305
Adjusted earnings	449	431	872	711
Latin America
Expenses
Capitalization of DAC			(353)	(299)
Latin America | Operating Segments
Revenues
Premiums	1,122	1,023	2,237	2,048
Universal life and investment-type product policy fees	373	352	743	687
Net investment income	398	418	784	797
Other revenues	11	10	22	22
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	1,904	1,803	3,786	3,554
Expenses
Policyholder benefits and claims and policyholder dividends	1,018	976	2,001	1,942
Policyholder liability remeasurement (gains) losses	(3)	3	(11)	(1)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	115	105	229	204
Capitalization of DAC	(175)	(148)	(353)	(299)
Amortization of DAC and VOBA	129	117	254	223
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	4	4	7	6
Other expenses	505	465	1,017	895
Total expenses	1,593	1,522	3,144	2,970
Provision for income tax expense (benefit)	85	62	183	150
Adjusted earnings	226	219	459	434
EMEA
Expenses
Capitalization of DAC			(243)	(227)
EMEA | Operating Segments
Revenues
Premiums	536	499	1,072	995
Universal life and investment-type product policy fees	77	75	154	152
Net investment income	54	47	108	92
Other revenues	8	8	15	16
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	675	629	1,349	1,255
Expenses
Policyholder benefits and claims and policyholder dividends	265	237	523	498
Policyholder liability remeasurement (gains) losses	1	2	1	(1)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	17	19	36	35
Capitalization of DAC	(115)	(119)	(243)	(227)
Amortization of DAC and VOBA	82	85	173	170
Amortization of negative VOBA	(1)	(1)	(2)	(2)
Interest expense on debt	0	0	0	0
Other expenses	328	314	660	614
Total expenses	577	537	1,148	1,087
Provision for income tax expense (benefit)	21	22	47	38
Adjusted earnings	77	70	154	130
MetLife Holdings
Expenses
Capitalization of DAC			(9)	(12)
MetLife Holdings | Operating Segments
Revenues
Premiums	692	719	1,405	1,442
Universal life and investment-type product policy fees	94	170	172	353
Net investment income	1,016	1,170	2,026	2,297
Other revenues	37	49	87	102
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	1,839	2,108	3,690	4,194
Expenses
Policyholder benefits and claims and policyholder dividends	1,252	1,341	2,503	2,710
Policyholder liability remeasurement (gains) losses	17	15	37	35
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	106	198	209	397
Capitalization of DAC	(4)	(6)	(9)	(12)
Amortization of DAC and VOBA	57	64	116	132
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	3	3	7	6
Other expenses	220	231	443	469
Total expenses	1,651	1,846	3,306	3,737
Provision for income tax expense (benefit)	35	51	72	88
Adjusted earnings	153	211	312	369
Corporate & Other
Expenses
Capitalization of DAC			(6)	(5)
Corporate & Other | Operating Segments
Revenues
Premiums	15	19	21	35
Universal life and investment-type product policy fees	1	1	1	1
Net investment income	95	80	201	130
Other revenues	97	106	195	207
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	208	206	418	373
Expenses
Policyholder benefits and claims and policyholder dividends	9	12	17	28
Policyholder liability remeasurement (gains) losses	0	0	0	0
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	0	0	0	0
Capitalization of DAC	(3)	(4)	(6)	(5)
Amortization of DAC and VOBA	1	4	3	5
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	246	244	499	491
Other expenses	188	229	382	406
Total expenses	441	485	895	925
Provision for income tax expense (benefit)	(47)	(83)	(117)	(186)
Adjusted earnings	$ (186)	$ (196)	$ (360)	$ (366)