Consolidated Supplementary Insurance Information (Income Statement Items) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	$ 54,982	$ 47,765	$ 47,637
Net Investment Income	15,916	21,395	17,117
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	54,304	49,492	46,675
Amortization of DAC and VOBA Charged to Other Expenses	1,931	2,555	3,160
Other Expenses (1)	10,804	10,907	11,080
U.S.
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	36,706	28,363	28,335
Net Investment Income	6,980	7,738	6,563
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	38,056	29,987	27,966
Amortization of DAC and VOBA Charged to Other Expenses	59	158	471
Other Expenses (1)	3,894	3,707	3,716
Asia
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	7,367	8,308	8,554
Net Investment Income	3,571	5,110	3,931
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	6,347	7,295	7,249
Amortization of DAC and VOBA Charged to Other Expenses	1,042	1,404	1,468
Other Expenses (1)	1,593	1,751	1,825
Latin America
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	4,401	3,718	3,257
Net Investment Income	1,318	1,207	991
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	4,046	3,442	2,857
Amortization of DAC and VOBA Charged to Other Expenses	339	285	276
Other Expenses (1)	1,057	989	971
EMEA
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	2,324	2,825	2,709
Net Investment Income	(864)	932	697
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	126	2,162	1,623
Amortization of DAC and VOBA Charged to Other Expenses	340	382	452
Other Expenses (1)	780	900	860
MetLife Holdings
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	4,198	4,514	4,757
Net Investment Income	4,690	6,157	4,900
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	5,735	6,571	6,983
Amortization of DAC and VOBA Charged to Other Expenses	142	317	485
Other Expenses (1)	1,629	1,839	1,976
Corporate & Other
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Premiums and Universal Life and Investment-Type Product Policy Fees	(14)	37	25
Net Investment Income	221	251	35
Policyholder Benefits and Claims and Interest Credited to Policyholder Account Balances	(6)	35	(3)
Amortization of DAC and VOBA Charged to Other Expenses	9	9	8
Other Expenses (1)	$ 1,851	$ 1,721	$ 1,732