Earnings Per Common Share (Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Weighted Average Shares:
Weighted average common stock outstanding - basic	775.4	823.8
Incremental common shares from assumed exercise or issuance of stock-based awards	5.8	6.7
Weighted average common stock outstanding - diluted	781.2	830.5
Net Income (Loss):
Net income (loss)	$ 85	$ 1,639
Less: Net income (loss) attributable to noncontrolling interests	5	5
Less: Preferred stock dividends	66	63
Net income (loss) available to MetLife, Inc.’s common shareholders	$ 14	$ 1,571
Basic	$ 0.02	$ 1.91
Diluted	$ 0.02	$ 1.89