Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 614	$ 495	$ 408	$ 85	$ 1,581	$ 1,167	$ 915	$ 1,639	$ 1,602	$ 5,302	$ 6,876
Other comprehensive income (loss):
Change in Gross Unrealized Temporary Loss									10,325	(56,497)	(12,840)
Deferred gains (losses) on derivatives									(1,811)	(85)	137
Future policy benefits discount rate remeasurement gains (losses)									(4,361)	31,804	10,102
Market risk benefit instrument-specific credit risk remeasurement gains (losses)									(102)	(219)	257
Foreign currency translation adjustments									296	(1,238)	(1,266)
Defined benefit plans adjustment									88	(279)	(328)
Other comprehensive income (loss), before income tax									4,259	(25,956)	(3,282)
Income tax (expense) benefit related to items of other comprehensive income (loss)									(898)	5,779	519
Other comprehensive income (loss), net of income tax									3,361	(20,177)	(2,763)
Comprehensive income (loss)									4,963	(14,875)	4,113
Less: Comprehensive income (loss) attributable to noncontrolling interest, net of income tax									6	11	24
Comprehensive income (loss) attributable to MetLife, Inc.									$ 4,957	$ (14,886)	$ 4,089