Investments (Changes in Net Unrealized Investment Gains Losses) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($)
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 17,671
Unrealized investment gains (losses) during the period	(59,334)
Unrealized investment gains (losses) relating to:
Policyholder liabilities	3,804
DAC, VOBA and DSI	6,707
Deferred income tax benefit (expense)	11,142
Net unrealized investment gains (losses)	(20,010)
Net unrealized investment gains (losses) attributable to noncontrolling interests	2
Balance, end of period	(20,008)
Change in net unrealized investment gains (losses)	(37,681)
Change in net unrealized investment gains (losses) attributable to noncontrolling interests	2
Change in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ (37,679)