Condensed Financial Information (Parent Company) (Condensed Statements of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Income Statements, Captions [Line Items]
Net investment income	$ 15,916	$ 21,395	$ 17,117
Other revenues	2,634	2,619	1,849
Net investment gains (losses)	(1,262)	1,529	(110)
Net derivative gains (losses)	(2,372)	(2,228)	1,349
Total revenues	69,898	71,080	67,842
Expenses
Other expenses	12,034	12,586	13,150
Total expenses	67,039	62,954	60,915
Income (loss) before provision for income tax and equity in earnings of subsidiaries	2,859	8,126	6,927
Provision for income tax expense (benefit)	301	1,551	1,509
Equity in earnings of subsidiaries	1,305	5,136	829
Net income (loss)	2,539	6,554	5,407
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
Comprehensive income (loss)	(35,463)	(599)	10,427
Parent Company
Condensed Income Statements, Captions [Line Items]
Net investment income	58	25	50
Other revenues	17	19	29
Net investment gains (losses)	332	1,655	(154)
Net derivative gains (losses)	129	116	(61)
Total revenues	536	1,815	(136)
Expenses
Interest expense	829	847	833
Other expenses	79	207	154
Total expenses	908	1,054	987
Income (loss) before provision for income tax and equity in earnings of subsidiaries	(372)	761	(1,123)
Provision for income tax expense (benefit)	(37)	202	(267)
Equity in earnings of subsidiaries	2,874	5,995	6,263
Net income (loss)	2,539	6,554	5,407
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
Comprehensive income (loss)	$ (35,463)	$ (599)	$ 10,427