Condensed Financial Information (Parent Company) (Condensed Statements of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Income Statements, Captions [Line Items]
Net investment income	$ 21,273	$ 19,908	$ 15,916
Other revenues	2,601	2,526	2,630
Net investment gains (losses)	(1,184)	(2,824)	(1,260)
Net derivative gains (losses)	(1,623)	(2,140)	(2,251)
Total revenues	70,986	66,905	68,770
Expenses
Other expenses	13,017	12,710	11,859
Total expenses	65,364	64,743	62,406
Income (loss) before provision for income tax and equity in earnings of subsidiaries	5,622	2,162	6,364
Provision for income tax expense (benefit)	1,178	560	1,062
Equity in earnings of subsidiaries	988	151	1,305
Net income (loss)	4,426	1,578	5,284
Less: Preferred stock dividends	200	198	185
Net income (loss) available to MetLife, Inc.’s common shareholders	4,226	1,380	5,099
Comprehensive income (loss)	2,482	4,957	(14,886)
Parent Company
Condensed Income Statements, Captions [Line Items]
Net investment income	177	188	58
Other revenues	16	17	17
Net investment gains (losses)	250	134	332
Net derivative gains (losses)	3	(41)	129
Total revenues	446	298	536
Expenses
Interest expense	920	907	829
Other expenses	215	140	79
Total expenses	1,135	1,047	908
Income (loss) before provision for income tax and equity in earnings of subsidiaries	(689)	(749)	(372)
Provision for income tax expense (benefit)	(59)	(128)	(37)
Equity in earnings of subsidiaries	5,056	2,199	5,619
Net income (loss)	4,426	1,578	5,284
Less: Preferred stock dividends	200	198	185
Net income (loss) available to MetLife, Inc.’s common shareholders	4,226	1,380	5,099
Comprehensive income (loss)	$ 2,482	$ 4,957	$ (14,886)