Earnings Per Common Share (Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Weighted Average Shares:
Weighted average common stock outstanding - basic	706.4	757.7	803.2
Incremental common shares from assumed exercise or issuance of stock-based awards	4.7	4.6	5.7
Weighted average common stock outstanding - diluted	711.1	762.3	808.9
Net Income (Loss):
Net income (loss)	$ 4,444	$ 1,602	$ 5,302
Less: Net income (loss) attributable to noncontrolling interests	18	24	18
Less: Preferred stock dividends	200	198	185
Net income (loss) available to MetLife, Inc.’s common shareholders	$ 4,226	$ 1,380	$ 5,099
Basic	$ 5.98	$ 1.82	$ 6.35
Diluted	$ 5.94	$ 1.81	$ 6.30