Segment Information (Earnings) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Revenues
Premiums	$ 11,723	$ 10,053
Universal life and investment-type product policy fees	1,229	1,248
Net investment income	4,885	5,436
Other revenues	687	674
Expenses
Policyholder liability remeasurement (gains) losses	(31)	(22)
Interest credited to policyholder account balances	1,647	2,290
Amortization of DAC, VOBA and negative VOBA	519	502
Interest expense on debt	258	264
Provision for income tax expense (benefit)	404	170
Adjusted earnings	$ 1,415	$ 1,401
Group Benefits
Expenses
Net investment income from equity method investments	1.00%	1.00%
RIS
Expenses
Net investment income from equity method investments	5.00%	4.00%
Asia
Expenses
Net investment income from equity method investments	11.00%	8.00%
Latin America
Expenses
Net investment income from equity method investments	1.00%	0.00%
MetLife Holdings
Expenses
Net investment income from equity method investments	4.00%	5.00%
Operating Segments
Expenses
Adjusted earnings	$ 1,597	$ 1,575
Operating Segments | Group Benefits
Revenues
Premiums	5,763	5,711
Universal life and investment-type product policy fees	233	222
Net investment income	315	315
Other revenues	434	397
Expenses
Policyholder benefits and claims and policyholder dividends	5,183	5,236
Policyholder liability remeasurement (gains) losses	(18)	(3)
Interest credited to policyholder account balances	44	48
Amortization of DAC, VOBA and negative VOBA	6	6
Interest expense on debt	0	0
Direct and Allocated Expenses	524	505
Other segment expenses	542	494
Provision for income tax expense (benefit)	97	75
Adjusted earnings	367	284
Operating Segments | RIS
Revenues
Premiums	2,284	675
Universal life and investment-type product policy fees	85	75
Net investment income	2,167	2,089
Other revenues	61	63
Expenses
Policyholder benefits and claims and policyholder dividends	3,121	1,471
Policyholder liability remeasurement (gains) losses	(15)	1
Interest credited to policyholder account balances	859	796
Amortization of DAC, VOBA and negative VOBA	17	15
Interest expense on debt	3	4
Direct and Allocated Expenses	85	80
Other segment expenses	27	31
Provision for income tax expense (benefit)	99	105
Adjusted earnings	401	399
Operating Segments | Asia
Revenues
Premiums	1,260	1,297
Universal life and investment-type product policy fees	406	426
Net investment income	1,206	1,108
Other revenues	15	21
Expenses
Policyholder benefits and claims and policyholder dividends	1,037	1,067
Policyholder liability remeasurement (gains) losses	(11)	(32)
Interest credited to policyholder account balances	711	647
Amortization of DAC, VOBA and negative VOBA	216	205
Interest expense on debt	0	0
Direct and Allocated Expenses	306	282
Other segment expenses	92	101
Provision for income tax expense (benefit)	162	159
Adjusted earnings	374	423
Operating Segments | Latin America
Revenues
Premiums	1,164	1,115
Universal life and investment-type product policy fees	340	370
Net investment income	407	386
Other revenues	9	11
Expenses
Policyholder benefits and claims and policyholder dividends	1,091	983
Policyholder liability remeasurement (gains) losses	(3)	(8)
Interest credited to policyholder account balances	98	114
Amortization of DAC, VOBA and negative VOBA	129	125
Interest expense on debt	4	3
Direct and Allocated Expenses	135	140
Other segment expenses	176	194
Provision for income tax expense (benefit)	72	98
Adjusted earnings	218	233
Operating Segments | EMEA
Revenues
Premiums	582	536
Universal life and investment-type product policy fees	78	77
Net investment income	58	54
Other revenues	8	7
Expenses
Policyholder benefits and claims and policyholder dividends	277	258
Policyholder liability remeasurement (gains) losses	0	0
Interest credited to policyholder account balances	17	19
Amortization of DAC, VOBA and negative VOBA	94	90
Interest expense on debt	0	0
Direct and Allocated Expenses	109	101
Other segment expenses	120	103
Provision for income tax expense (benefit)	26	26
Adjusted earnings	83	77
Operating Segments | MetLife Holdings
Revenues
Premiums	657	713
Universal life and investment-type product policy fees	86	78
Net investment income	989	1,010
Other revenues	37	50
Expenses
Policyholder benefits and claims and policyholder dividends	1,200	1,251
Policyholder liability remeasurement (gains) losses	16	20
Interest credited to policyholder account balances	88	103
Amortization of DAC, VOBA and negative VOBA	55	59
Interest expense on debt	3	4
Direct and Allocated Expenses	168	165
Other segment expenses	49	53
Provision for income tax expense (benefit)	36	37
Adjusted earnings	$ 154	$ 159