Segment Information (Earnings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues
Premiums	$ 44,945	$ 44,283	$ 48,510
Universal life and investment-type product policy fees	4,974	5,152	5,225
Net investment income	21,273	19,908	15,916
Other revenues	2,601	2,526	2,630
Expenses
Policyholder liability remeasurement (gains) losses	(206)	(45)	114
Interest credited to policyholder account balances	8,339	7,860	3,894
Amortization of DAC, VOBA and negative VOBA	2,021	1,926	1,802
Interest expense on debt	1,037	1,045	938
Provision for income tax expense (benefit)	1,178	560	1,062
Adjusted earnings	$ 5,996	$ 5,723	$ 5,978
Group Benefits
Expenses
Net investment income from equity method investments	0.00%	0.00%	1.00%
RIS
Expenses
Net investment income from equity method investments	3.00%	1.00%	6.00%
Asia
Expenses
Net investment income from equity method investments	12.00%	4.00%	12.00%
Latin America
Expenses
Net investment income from equity method investments	1.00%	1.00%	3.00%
MetLife Holdings
Expenses
Net investment income from equity method investments	3.00%	2.00%	6.00%
Operating Segments
Expenses
Adjusted earnings	$ 6,705	$ 6,483	$ 6,593
Operating Segments | Group Benefits
Revenues
Premiums	22,427	21,558	21,051
Universal life and investment-type product policy fees	909	878	855
Net investment income	1,252	1,301	1,136
Other revenues	1,534	1,493	1,360
Expenses
Policyholder benefits and claims and policyholder dividends	19,824	19,164	19,076
Policyholder liability remeasurement (gains) losses	(1)	(28)	7
Interest credited to policyholder account balances	191	193	143
Amortization of DAC, VOBA and negative VOBA	26	26	26
Interest expense on debt	2	2	1
Direct and Allocated Expenses	2,000	1,896	1,793
Other expenses	2,049	1,880	1,667
Provision for income tax expense (benefit)	425	442	357
Adjusted earnings	1,606	1,655	1,332
Operating Segments | RIS
Revenues
Premiums	8,034	8,248	13,619
Universal life and investment-type product policy fees	314	313	303
Net investment income	8,482	7,803	6,204
Other revenues	246	271	392
Expenses
Policyholder benefits and claims and policyholder dividends	11,246	11,269	16,163
Policyholder liability remeasurement (gains) losses	(170)	(131)	(36)
Interest credited to policyholder account balances	3,371	2,887	1,914
Amortization of DAC, VOBA and negative VOBA	66	49	40
Interest expense on debt	15	14	8
Direct and Allocated Expenses	309	275	260
Other expenses	139	114	111
Provision for income tax expense (benefit)	433	450	423
Adjusted earnings	1,667	1,708	1,635
Operating Segments | Asia
Revenues
Premiums	4,991	5,251	5,563
Universal life and investment-type product policy fees	1,690	1,632	1,693
Net investment income	4,658	3,957	3,909
Other revenues	76	86	90
Expenses
Policyholder benefits and claims and policyholder dividends	4,083	4,333	4,564
Policyholder liability remeasurement (gains) losses	(35)	105	69
Interest credited to policyholder account balances	2,695	2,301	2,003
Amortization of DAC, VOBA and negative VOBA	832	772	721
Interest expense on debt	0	0	0
Direct and Allocated Expenses	1,176	1,172	1,202
Other expenses	413	403	421
Provision for income tax expense (benefit)	630	558	658
Adjusted earnings	1,621	1,282	1,617
Operating Segments | Latin America
Revenues
Premiums	4,476	4,287	3,224
Universal life and investment-type product policy fees	1,419	1,398	1,175
Net investment income	1,650	1,644	1,593
Other revenues	41	42	39
Expenses
Policyholder benefits and claims and policyholder dividends	4,127	4,094	3,320
Policyholder liability remeasurement (gains) losses	(9)	(25)	(21)
Interest credited to policyholder account balances	438	426	335
Amortization of DAC, VOBA and negative VOBA	503	468	410
Interest expense on debt	15	11	12
Direct and Allocated Expenses	560	578	493
Other expenses	743	682	533
Provision for income tax expense (benefit)	328	297	220
Adjusted earnings	881	840	729
Operating Segments | EMEA
Revenues
Premiums	2,202	2,016	1,962
Universal life and investment-type product policy fees	314	298	284
Net investment income	222	197	160
Other revenues	32	32	35
Expenses
Policyholder benefits and claims and policyholder dividends	1,100	984	976
Policyholder liability remeasurement (gains) losses	7	(3)	(6)
Interest credited to policyholder account balances	70	72	71
Amortization of DAC, VOBA and negative VOBA	355	344	318
Interest expense on debt	0	0	0
Direct and Allocated Expenses	426	404	389
Other expenses	457	399	371
Provision for income tax expense (benefit)	72	78	73
Adjusted earnings	283	265	249
Operating Segments | MetLife Holdings
Revenues
Premiums	2,780	2,881	3,066
Universal life and investment-type product policy fees	326	632	902
Net investment income	3,985	4,494	4,914
Other revenues	166	195	155
Expenses
Policyholder benefits and claims and policyholder dividends	4,954	5,350	5,636
Policyholder liability remeasurement (gains) losses	2	37	101
Interest credited to policyholder account balances	390	730	813
Amortization of DAC, VOBA and negative VOBA	229	258	270
Interest expense on debt	14	13	8
Direct and Allocated Expenses	646	666	669
Other expenses	223	239	255
Provision for income tax expense (benefit)	152	176	254
Adjusted earnings	$ 647	$ 733	$ 1,031