Consolidated Supplementary Insurance Information (Income Statement Items) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	$ 49,919	$ 49,435	$ 53,735
Net Investment Income	21,273	19,908	15,916
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	52,861	52,405	53,515
Market risk benefit remeasurement (gains) losses	(1,109)	(994)	(3,674)
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	2,021	1,926	1,802
Other Expenses (1)	11,591	11,406	10,763
Group Benefits | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	23,367	22,436	21,906
Net Investment Income	1,178	1,148	1,081
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	20,033	19,329	19,226
Market risk benefit remeasurement (gains) losses	0	0	0
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	26	26	26
Other Expenses (1)	4,062	3,778	3,460
RIS | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	8,348	8,561	13,923
Net Investment Income	8,291	7,354	5,899
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	14,586	14,057	18,124
Market risk benefit remeasurement (gains) losses	11	(29)	(314)
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	66	49	40
Other Expenses (1)	493	403	380
Asia | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	6,681	6,883	7,256
Net Investment Income	5,099	4,307	3,571
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	6,846	6,941	6,199
Market risk benefit remeasurement (gains) losses	7	(43)	(90)
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	832	772	721
Other Expenses (1)	1,600	1,584	1,625
Latin America | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	5,895	5,685	4,399
Net Investment Income	1,608	1,610	1,318
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	4,785	4,801	4,092
Market risk benefit remeasurement (gains) losses	0	0	0
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	503	468	410
Other Expenses (1)	1,311	1,263	1,032
EMEA | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	2,516	2,314	2,298
Net Investment Income	847	885	(864)
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	1,797	1,737	30
Market risk benefit remeasurement (gains) losses	(54)	(40)	(126)
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	355	344	326
Other Expenses (1)	891	811	783
MetLife Holdings | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	3,106	3,513	3,968
Net Investment Income	3,802	4,234	4,633
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	4,807	5,517	5,849
Market risk benefit remeasurement (gains) losses	(1,074)	(882)	(3,144)
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	229	258	270
Other Expenses (1)	1,461	1,527	1,632
Corporate And Other | Operating Segments [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	6	43	(15)
Net Investment Income	448	370	278
Policyholder Benefits and Claims, Policyholder Liability Remeasurement (Gains) Losses and Interest Credited to PABs	7	23	(5)
Market risk benefit remeasurement (gains) losses	1	0	0
Amortization of DAC, VOBA and Negative VOBA Charged to Other Expenses	10	9	9
Other Expenses (1)	$ 1,773	$ 2,040	$ 1,851