Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,418	$ 5,909	$ 5,128
Other comprehensive income (loss):
Unrealized investment gains (losses), net of related offsets	5,198	14,591	(8,719)
Unrealized gains (losses) on derivatives	(286)	60	674
Foreign currency translation adjustments	1,169	(42)	(587)
Defined benefit plans adjustment	181	30	263
Other comprehensive income (loss), before income tax	6,262	14,639	(8,369)
Income tax (expense) benefit related to items of other comprehensive income (loss)	(1,237)	(3,324)	1,754
Other comprehensive income (loss), net of income tax	5,025	11,315	(6,615)
Comprehensive income (loss)	10,443	17,224	(1,487)
Less: Comprehensive income (loss) attributable to noncontrolling interest, net of income tax	16	16	7
Comprehensive income (loss) attributable to MetLife, Inc.	$ 10,427	$ 17,208	$ (1,494)