Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,128	$ 4,020	$ 854
Other comprehensive income (loss):
Unrealized investment gains (losses), net of related offsets	(8,719)	4,623	796
Unrealized gains (losses) on derivatives	674	(1,165)	573
Foreign currency translation adjustments	(587)	767	(363)
Defined benefit plans adjustment	263	144	131
Other comprehensive income (loss), before income tax	(8,369)	4,369	1,137
Income tax (expense) benefit related to items of other comprehensive income (loss)	1,754	(984)	(450)
Other comprehensive income (loss), net of income tax	(6,615)	3,385	687
Comprehensive income (loss)	(1,487)	7,405	1,541
Less: Comprehensive income (loss) attributable to noncontrolling interest, net of income tax	7	14	92
Comprehensive income (loss) attributable to MetLife, Inc.	$ (1,494)	$ 7,391	$ 1,449