Earnings Per Common Share (Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted Average Shares:
Weighted average common stock outstanding - basic	803.2	862.7	907.8
Incremental common shares from assumed exercise or issuance of stock-based awards	5.7	6.7	5.4
Weighted average common stock outstanding - diluted	808.9	869.4	913.2
Net Income (Loss):
Net income (loss)	$ 2,558	$ 6,575	$ 5,418
Less: Net income (loss) attributable to noncontrolling interests	19	21	11
Less: Preferred stock dividends	185	195	202
Preferred stock redemption premium	0	6	14
Net income (loss) available to MetLife, Inc.’s common shareholders	$ 2,354	$ 6,353	$ 5,191
Basic	$ 2.93	$ 7.36	$ 5.72
Diluted	$ 2.91	$ 7.31	$ 5.68