Segment Information (Earnings) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues
Premiums	$ 10,053	$ 9,589
Universal life and investment-type product policy fees	1,248	1,289
Net investment income	5,436	4,645
Other revenues	674	639
Net investment gains (losses)	(375)	(684)
Net derivative gains (losses)	(979)	(90)
Total revenues	16,057	15,388
Expenses
Policyholder benefits and claims and policyholder dividends	10,221	10,031
Policyholder liability remeasurement (gains) losses	(22)	(9)
Market risk benefit remeasurement (gains) losses	(694)	188
Interest credited to policyholder account balances	2,290	1,864
Capitalization of DAC	(740)	(718)
Amortization of DAC and VOBA	508	470
Amortization of negative VOBA	(6)	(7)
Interest expense on debt	264	255
Other expenses	3,191	3,057
Total expenses	15,012	15,131
Provision for income tax expense (benefit)	170	172
Net income (loss)	875	85
Operating Segments
Revenues
Premiums	10,053	9,589
Universal life and investment-type product policy fees	1,248	1,289
Net investment income	5,068	4,606
Other revenues	647	642
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	17,016	16,126
Expenses
Policyholder benefits and claims and policyholder dividends	10,274	9,961
Policyholder liability remeasurement (gains) losses	(22)	(9)
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	1,727	1,542
Capitalization of DAC	(740)	(718)
Amortization of DAC and VOBA	508	470
Amortization of negative VOBA	(6)	(7)
Interest expense on debt	264	255
Other expenses	3,180	3,030
Total expenses	15,185	14,524
Provision for income tax expense (benefit)	430	352
Adjusted earnings	1,401	1,250
Segment Reconciling Items
Revenues
Premiums	0	0
Universal life and investment-type product policy fees	0	0
Net investment income	368	39
Other revenues	27	(3)
Net investment gains (losses)	(375)	(684)
Net derivative gains (losses)	(979)	(90)
Total revenues	(959)	(738)
Expenses
Policyholder benefits and claims and policyholder dividends	(53)	70
Policyholder liability remeasurement (gains) losses	0	0
Market risk benefit remeasurement (gains) losses	(694)	188
Interest credited to policyholder account balances	563	322
Capitalization of DAC	0	0
Amortization of DAC and VOBA	0	0
Amortization of negative VOBA	0	0
Interest expense on debt	0	0
Other expenses	11	27
Total expenses	(173)	607
Provision for income tax expense (benefit)	(260)	(180)
Group Benefits
Expenses
Capitalization of DAC	(4)	(6)
Group Benefits | Operating Segments
Revenues
Premiums	5,711	5,451
Universal life and investment-type product policy fees	222	218
Net investment income	315	310
Other revenues	397	380
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	6,645	6,359
Expenses
Policyholder benefits and claims and policyholder dividends	5,236	4,994
Policyholder liability remeasurement (gains) losses	(3)	(4)
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	48	46
Capitalization of DAC	(4)	(6)
Amortization of DAC and VOBA	6	6
Amortization of negative VOBA	0	0
Interest expense on debt	0	0
Other expenses	1,003	932
Total expenses	6,286	5,968
Provision for income tax expense (benefit)	75	84
Adjusted earnings	284	307
RIS
Expenses
Capitalization of DAC	(61)	(45)
RIS | Operating Segments
Revenues
Premiums	675	501
Universal life and investment-type product policy fees	75	79
Net investment income	2,089	1,814
Other revenues	63	68
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	2,902	2,462
Expenses
Policyholder benefits and claims and policyholder dividends	1,471	1,225
Policyholder liability remeasurement (gains) losses	1	(29)
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	796	646
Capitalization of DAC	(61)	(45)
Amortization of DAC and VOBA	15	11
Amortization of negative VOBA	0	0
Interest expense on debt	4	3
Other expenses	172	146
Total expenses	2,398	1,957
Provision for income tax expense (benefit)	105	105
Adjusted earnings	399	400
Asia
Expenses
Capitalization of DAC	(361)	(401)
Asia | Operating Segments
Revenues
Premiums	1,297	1,377
Universal life and investment-type product policy fees	426	397
Net investment income	1,108	881
Other revenues	21	20
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	2,852	2,675
Expenses
Policyholder benefits and claims and policyholder dividends	1,067	1,130
Policyholder liability remeasurement (gains) losses	(32)	11
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	647	536
Capitalization of DAC	(361)	(401)
Amortization of DAC and VOBA	210	193
Amortization of negative VOBA	(5)	(6)
Interest expense on debt	0	0
Other expenses	744	807
Total expenses	2,270	2,270
Provision for income tax expense (benefit)	159	125
Adjusted earnings	423	280
Latin America
Expenses
Capitalization of DAC	(178)	(151)
Latin America | Operating Segments
Revenues
Premiums	1,115	1,025
Universal life and investment-type product policy fees	370	335
Net investment income	386	379
Other revenues	11	12
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	1,882	1,751
Expenses
Policyholder benefits and claims and policyholder dividends	983	966
Policyholder liability remeasurement (gains) losses	(8)	(4)
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	114	99
Capitalization of DAC	(178)	(151)
Amortization of DAC and VOBA	125	106
Amortization of negative VOBA	0	0
Interest expense on debt	3	2
Other expenses	512	430
Total expenses	1,551	1,448
Provision for income tax expense (benefit)	98	88
Adjusted earnings	233	215
EMEA
Expenses
Capitalization of DAC	(128)	(108)
EMEA | Operating Segments
Revenues
Premiums	536	496
Universal life and investment-type product policy fees	77	77
Net investment income	54	45
Other revenues	7	8
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	674	626
Expenses
Policyholder benefits and claims and policyholder dividends	258	261
Policyholder liability remeasurement (gains) losses	0	(3)
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	19	16
Capitalization of DAC	(128)	(108)
Amortization of DAC and VOBA	91	85
Amortization of negative VOBA	(1)	(1)
Interest expense on debt	0	0
Other expenses	332	300
Total expenses	571	550
Provision for income tax expense (benefit)	26	16
Adjusted earnings	77	60
MetLife Holdings
Expenses
Capitalization of DAC	(5)	(6)
MetLife Holdings | Operating Segments
Revenues
Premiums	713	723
Universal life and investment-type product policy fees	78	183
Net investment income	1,010	1,127
Other revenues	50	53
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	1,851	2,086
Expenses
Policyholder benefits and claims and policyholder dividends	1,251	1,369
Policyholder liability remeasurement (gains) losses	20	20
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	103	199
Capitalization of DAC	(5)	(6)
Amortization of DAC and VOBA	59	68
Amortization of negative VOBA	0	0
Interest expense on debt	4	3
Other expenses	223	238
Total expenses	1,655	1,891
Provision for income tax expense (benefit)	37	37
Adjusted earnings	159	158
Corporate & Other
Expenses
Capitalization of DAC	(3)	(1)
Corporate & Other | Operating Segments
Revenues
Premiums	6	16
Universal life and investment-type product policy fees	0	0
Net investment income	106	50
Other revenues	98	101
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	210	167
Expenses
Policyholder benefits and claims and policyholder dividends	8	16
Policyholder liability remeasurement (gains) losses	0	0
Market risk benefit remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	0	0
Capitalization of DAC	(3)	(1)
Amortization of DAC and VOBA	2	1
Amortization of negative VOBA	0	0
Interest expense on debt	253	247
Other expenses	194	177
Total expenses	454	440
Provision for income tax expense (benefit)	(70)	(103)
Adjusted earnings	$ (174)	$ (170)