Policyholder Account Balances - Amounts on Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021	Jan. 01, 2021
Policyholder Account Balance [Line Items]
Policyholder Account Balance	$ 213,933	$ 210,597			$ 211,737
Other Products
Policyholder Account Balance [Line Items]
Policyholder Account Balance	16,136	15,936			19,441
Group Insurance Policy | U.S.
Policyholder Account Balance [Line Items]
Policyholder Account Balance	7,785	8,028	$ 8,061	$ 7,893	7,586
Capital Markets Investment Products and Stable Value GICs | U.S.
Policyholder Account Balance [Line Items]
Policyholder Account Balance	63,417	63,723	63,538	62,521	62,908
Annuities and Risk Solutions | U.S.
Policyholder Account Balance [Line Items]
Policyholder Account Balance	17,064	15,549	15,107	14,431	13,643
Universal And Variable Life Contracts [Member] | Asia
Policyholder Account Balance [Line Items]
Policyholder Account Balance	47,630	46,417	44,714	46,590	43,868
Fixed Annuity | Asia
Policyholder Account Balance [Line Items]
Policyholder Account Balance	35,480	32,454	30,114	30,976	31,422
Fixed Annuity | MetLife Holdings
Policyholder Account Balance [Line Items]
Policyholder Account Balance	12,006	13,286	13,701	14,398	15,234
Variable Annuity [Member] | EMEA
Policyholder Account Balance [Line Items]
Policyholder Account Balance	2,571	2,802	2,610	4,215	4,779
Life and Other | MetLife Holdings
Policyholder Account Balance [Line Items]
Policyholder Account Balance	$ 11,844	$ 12,402	$ 12,544	$ 12,699	$ 12,856