Segment Information (Earnings) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues
Premiums	$ 10,647	$ 11,230	$ 32,328	$ 32,497
Universal life and investment-type product policy fees	1,228	1,334	3,757	3,911
Net investment income	5,227	4,825	15,868	14,542
Other revenues	648	606	1,960	1,866
Net investment gains (losses)	(77)	(927)	(873)	(2,650)
Net derivative gains (losses)	767	(1,202)	(720)	(2,289)
Total revenues	18,440	15,866	52,320	47,877
Expenses
Policyholder benefits and claims and policyholder dividends	10,747	11,283	32,601	33,274
Policyholder liability remeasurement (gains) losses	(132)	(17)	(164)	(42)
Market risk benefit remeasurement (gains) losses	531	(796)	(345)	(1,425)
Interest credited to policyholder account balances	2,037	1,658	6,327	5,455
Capitalization of DAC	(691)	(742)	(2,114)	(2,189)
Amortization of DAC and VOBA	516	499	1,523	1,448
Amortization of negative VOBA	(7)	(7)	(19)	(20)
Interest expense on debt	257	265	778	776
Other expenses	3,188	3,189	9,492	9,379
Total expenses	16,446	15,332	48,079	46,656
Provision for income tax expense (benefit)	653	39	1,072	233
Net income (loss)	1,341	495	3,169	988
Operating Segments
Revenues
Premiums	10,631	11,230	32,312	32,497
Universal life and investment-type product policy fees	1,228	1,334	3,757	3,911
Net investment income	5,143	5,056	15,371	14,702
Other revenues	612	617	1,873	1,887
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	17,614	18,237	53,313	52,997
Expenses
Policyholder benefits and claims and policyholder dividends	10,797	11,352	32,631	33,243
Policyholder liability remeasurement (gains) losses	(132)	(17)	(164)	(42)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	1,815	1,705	5,323	4,889
Capitalization of DAC	(691)	(742)	(2,114)	(2,189)
Amortization of DAC and VOBA	516	499	1,523	1,448
Amortization of negative VOBA	(7)	(7)	(19)	(20)
Interest expense on debt	257	265	778	776
Other expenses	3,159	3,159	9,443	9,302
Total expenses	15,714	16,214	47,401	47,407
Provision for income tax expense (benefit)	458	468	1,407	1,261
Adjusted earnings	1,442	1,555	4,505	4,329
Segment Reconciling Items
Revenues
Premiums	16	0	16	0
Universal life and investment-type product policy fees	0	0	0	0
Net investment income	84	(231)	497	(160)
Other revenues	36	(11)	87	(21)
Net investment gains (losses)	(77)	(927)	(873)	(2,650)
Net derivative gains (losses)	767	(1,202)	(720)	(2,289)
Total revenues	826	(2,371)	(993)	(5,120)
Expenses
Policyholder benefits and claims and policyholder dividends	(50)	(69)	(30)	31
Policyholder liability remeasurement (gains) losses	0	0	0	0
Market risk benefit remeasurement (gains) losses	531	(796)	(345)	(1,425)
Interest credited to policyholder account balances	222	(47)	1,004	566
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	29	30	49	77
Total expenses	732	(882)	678	(751)
Provision for income tax expense (benefit)	195	(429)	(335)	(1,028)
Group Benefits
Expenses
Capitalization of DAC			(13)	(16)
Group Benefits | Operating Segments
Revenues
Premiums	5,538	5,276	16,848	16,154
Universal life and investment-type product policy fees	231	219	682	660
Net investment income	311	330	939	967
Other revenues	377	371	1,156	1,114
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	6,457	6,196	19,625	18,895
Expenses
Policyholder benefits and claims and policyholder dividends	4,927	4,592	14,943	14,452
Policyholder liability remeasurement (gains) losses	0	(29)	(1)	(31)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	49	50	145	144
Capitalization of DAC	(4)	(5)	(13)	(16)
Amortization of DAC and VOBA	6	6	19	19
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	0	0	1	1
Other expenses	1,007	937	3,026	2,819
Total expenses	5,985	5,551	18,120	17,388
Provision for income tax expense (benefit)	99	135	315	318
Adjusted earnings	373	510	1,190	1,189
RIS
Expenses
Capitalization of DAC			(160)	(136)
RIS | Operating Segments
Revenues
Premiums	1,451	2,330	4,574	5,512
Universal life and investment-type product policy fees	67	82	215	232
Net investment income	2,133	2,009	6,339	5,771
Other revenues	61	66	185	205
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	3,712	4,487	11,313	11,720
Expenses
Policyholder benefits and claims and policyholder dividends	2,247	3,100	6,966	7,766
Policyholder liability remeasurement (gains) losses	(148)	(76)	(170)	(116)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	874	756	2,508	2,104
Capitalization of DAC	(53)	(41)	(160)	(136)
Amortization of DAC and VOBA	14	13	45	36
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	4	3	11	10
Other expenses	183	138	500	430
Total expenses	3,121	3,893	9,700	10,094
Provision for income tax expense (benefit)	119	124	332	339
Adjusted earnings	472	470	1,281	1,287
Asia
Expenses
Capitalization of DAC			(1,032)	(1,202)
Asia | Operating Segments
Revenues
Premiums	1,272	1,312	3,785	3,999
Universal life and investment-type product policy fees	420	411	1,280	1,204
Net investment income	1,132	1,023	3,407	2,954
Other revenues	18	20	57	61
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	2,842	2,766	8,529	8,218
Expenses
Policyholder benefits and claims and policyholder dividends	1,035	1,095	3,090	3,282
Policyholder liability remeasurement (gains) losses	60	108	24	92
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	683	576	1,987	1,682
Capitalization of DAC	(336)	(404)	(1,032)	(1,202)
Amortization of DAC and VOBA	217	204	634	587
Amortization of negative VOBA	(6)	(6)	(16)	(17)
Interest expense on debt	0	0	0	0
Other expenses	758	788	2,204	2,373
Total expenses	2,411	2,361	6,891	6,797
Provision for income tax expense (benefit)	125	130	460	435
Adjusted earnings	306	275	1,178	986
Latin America
Expenses
Capitalization of DAC			(527)	(470)
Latin America | Operating Segments
Revenues
Premiums	1,141	1,116	3,378	3,164
Universal life and investment-type product policy fees	346	359	1,089	1,046
Net investment income	435	365	1,219	1,162
Other revenues	9	9	31	31
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	1,931	1,849	5,717	5,403
Expenses
Policyholder benefits and claims and policyholder dividends	1,091	1,020	3,092	2,962
Policyholder liability remeasurement (gains) losses	(18)	(4)	(29)	(5)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	108	106	337	310
Capitalization of DAC	(174)	(171)	(527)	(470)
Amortization of DAC and VOBA	126	121	380	344
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	4	2	11	8
Other expenses	485	493	1,502	1,388
Total expenses	1,622	1,567	4,766	4,537
Provision for income tax expense (benefit)	88	83	271	233
Adjusted earnings	221	199	680	633
EMEA
Expenses
Capitalization of DAC			(362)	(341)
EMEA | Operating Segments
Revenues
Premiums	562	502	1,634	1,497
Universal life and investment-type product policy fees	84	79	238	231
Net investment income	55	51	163	143
Other revenues	9	7	24	23
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	710	639	2,059	1,894
Expenses
Policyholder benefits and claims and policyholder dividends	276	230	799	728
Policyholder liability remeasurement (gains) losses	9	(9)	10	(10)
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	17	19	53	54
Capitalization of DAC	(119)	(114)	(362)	(341)
Amortization of DAC and VOBA	92	87	265	257
Amortization of negative VOBA	(1)	(1)	(3)	(3)
Interest expense on debt	0	0	0	0
Other expenses	342	315	1,002	929
Total expenses	616	527	1,764	1,614
Provision for income tax expense (benefit)	24	24	71	62
Adjusted earnings	70	88	224	218
MetLife Holdings
Expenses
Capitalization of DAC			(13)	(17)
MetLife Holdings | Operating Segments
Revenues
Premiums	673	685	2,078	2,127
Universal life and investment-type product policy fees	80	184	252	537
Net investment income	981	1,153	3,007	3,450
Other revenues	40	41	127	143
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	1,774	2,063	5,464	6,257
Expenses
Policyholder benefits and claims and policyholder dividends	1,221	1,311	3,724	4,021
Policyholder liability remeasurement (gains) losses	(35)	(7)	2	28
Market risk benefit remeasurement (gains) losses	0	0	0	0
Interest credited to policyholder account balances	84	198	293	595
Capitalization of DAC	(4)	(5)	(13)	(17)
Amortization of DAC and VOBA	58	65	174	197
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	4	4	11	10
Other expenses	220	238	663	707
Total expenses	1,548	1,804	4,854	5,541
Provision for income tax expense (benefit)	44	51	116	139
Adjusted earnings	182	208	494	577
Corporate & Other
Expenses
Capitalization of DAC			(7)	(7)
Corporate & Other | Operating Segments
Revenues
Premiums	(6)	9	15	44
Universal life and investment-type product policy fees	0	0	1	1
Net investment income	96	125	297	255
Other revenues	98	103	293	310
Net investment gains (losses)	0	0	0	0
Net derivative gains (losses)	0	0	0	0
Total revenues	188	237	606	610
Expenses
Policyholder benefits and claims and policyholder dividends	0	4	17	32
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	(1)	(2)	(7)	(7)
Amortization of DAC and VOBA	3	3	6	8
Amortization of negative VOBA	0	0	0	0
Interest expense on debt	245	256	744	747
Other expenses	164	250	546	656
Total expenses	411	511	1,306	1,436
Provision for income tax expense (benefit)	(41)	(79)	(158)	(265)
Adjusted earnings	$ (182)	$ (195)	$ (542)	$ (561)