Segment Information (Earnings) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues
Premiums	$ 17,547	$ 9,455			$ 40,039	$ 28,914
Universal life and investment-type product policy fees	1,302	1,521			4,236	4,334
Net investment income	3,585	5,568			11,452	16,162
Other revenues	730	663			2,006	1,958
Net investment gains (losses)	(414)	(84)			(1,617)	1,655
Net derivative gains (losses)	(480)	(218)			(2,534)	(2,032)
Total revenues	22,270	16,905			53,582	50,991
Expenses
Policyholder benefits and claims and policyholder dividends	18,148	10,292			41,522	30,703
Interest credited to policyholder account balances	980	1,287			2,102	4,153
Capitalization of DAC	(615)	(635)			(1,887)	(2,052)
Amortization of DAC and VOBA	218	816			1,371	1,943
Amortization of negative VOBA	(12)	(6)			(31)	(25)
Interest expense on debt	239	240			690	696
Other expenses	2,893	2,869			8,683	8,753
Total expenses	21,851	14,863			52,450	44,171
Provision for income tax expense (benefit)	19	453			(80)	1,456
Net income (loss)	400	1,589	$ 812	$ 3,775	1,212	5,364
Operating Segments [Member]
Revenues
Premiums	17,547	9,398			39,998	27,992
Universal life and investment-type product policy fees	1,290	1,437			4,187	4,189
Net investment income	4,163	5,668			13,659	16,079
Other revenues	690	584			1,868	1,773
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	23,690	17,087			59,712	50,033
Expenses
Policyholder benefits and claims and policyholder dividends	18,291	10,111			41,631	29,782
Interest credited to policyholder account balances	1,282	1,167			3,601	3,458
Capitalization of DAC	(615)	(620)			(1,876)	(1,948)
Amortization of DAC and VOBA	335	758			1,477	1,806
Amortization of negative VOBA	(12)	(6)			(31)	(25)
Interest expense on debt	239	240			690	695
Other expenses	2,833	2,760			8,477	8,314
Total expenses	22,353	14,410			53,969	42,082
Provision for income tax expense (benefit)	307	552			1,268	1,669
Adjusted earnings	1,030	2,125			4,475	6,282
Segment Reconciling Items [Member]
Revenues
Premiums	0	57			41	922
Universal life and investment-type product policy fees	12	84			49	145
Net investment income	(578)	(100)			(2,207)	83
Other revenues	40	79			138	185
Net investment gains (losses)	(414)	(84)			(1,617)	1,655
Net derivative gains (losses)	(480)	(218)			(2,534)	(2,032)
Total revenues	(1,420)	(182)			(6,130)	958
Expenses
Policyholder benefits and claims and policyholder dividends	(143)	181			(109)	921
Interest credited to policyholder account balances	(302)	120			(1,499)	695
Capitalization of DAC	0	(15)			(11)	(104)
Amortization of DAC and VOBA	(117)	58			(106)	137
Amortization of negative VOBA	0	0			0	0
Interest expense on debt	0	0			0	1
Other expenses	60	109			206	439
Total expenses	(502)	453			(1,519)	2,089
Provision for income tax expense (benefit)	(288)	(99)			(1,348)	(213)
U.S. | Operating Segments [Member]
Revenues
Premiums	14,164	5,746			29,582	16,919
Universal life and investment-type product policy fees	286	279			867	858
Net investment income	1,716	2,098			5,300	6,106
Other revenues	516	383			1,347	1,159
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	16,682	8,506			37,096	25,042
Expenses
Policyholder benefits and claims and policyholder dividends	14,265	6,118			30,151	17,999
Interest credited to policyholder account balances	478	362			1,212	1,080
Capitalization of DAC	(23)	(17)			(60)	(48)
Amortization of DAC and VOBA	15	26			43	50
Amortization of negative VOBA	0	0			0	0
Interest expense on debt	3	1			6	4
Other expenses	1,003	886			2,931	2,695
Total expenses	15,741	7,376			34,283	21,780
Provision for income tax expense (benefit)	197	235			588	681
Adjusted earnings	744	895			2,225	2,581
Asia | Operating Segments [Member]
Revenues
Premiums	1,347	1,594			4,295	4,861
Universal life and investment-type product policy fees	421	477			1,367	1,371
Net investment income	827	1,354			3,081	3,776
Other revenues	21	17			66	54
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	2,616	3,442			8,809	10,062
Expenses
Policyholder benefits and claims and policyholder dividends	1,257	1,220			3,670	3,750
Interest credited to policyholder account balances	497	513			1,488	1,498
Capitalization of DAC	(358)	(373)			(1,120)	(1,203)
Amortization of DAC and VOBA	190	470			799	1,080
Amortization of negative VOBA	(11)	(5)			(27)	(20)
Interest expense on debt	0	0			0	0
Other expenses	749	811			2,349	2,542
Total expenses	2,324	2,636			7,159	7,647
Provision for income tax expense (benefit)	95	237			487	703
Adjusted earnings	197	569			1,163	1,712
Latin America | Operating Segments [Member]
Revenues
Premiums	823	705			2,381	1,936
Universal life and investment-type product policy fees	290	274			876	831
Net investment income	399	306			1,180	913
Other revenues	10	9			29	30
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	1,522	1,294			4,466	3,710
Expenses
Policyholder benefits and claims and policyholder dividends	874	885			2,454	2,370
Interest credited to policyholder account balances	89	63			241	182
Capitalization of DAC	(130)	(109)			(363)	(304)
Amortization of DAC and VOBA	68	62			238	205
Amortization of negative VOBA	0	0			0	0
Interest expense on debt	3	2			10	4
Other expenses	398	363			1,122	1,041
Total expenses	1,302	1,266			3,702	3,498
Provision for income tax expense (benefit)	49	(1)			184	46
Adjusted earnings	171	29			580	166
EMEA | Operating Segments [Member]
Revenues
Premiums	475	532			1,476	1,751
Universal life and investment-type product policy fees	62	128			236	302
Net investment income	40	46			119	171
Other revenues	8	10			25	39
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	585	716			1,856	2,263
Expenses
Policyholder benefits and claims and policyholder dividends	239	268			758	944
Interest credited to policyholder account balances	16	17			53	66
Capitalization of DAC	(96)	(110)			(305)	(359)
Amortization of DAC and VOBA	79	118			260	274
Amortization of negative VOBA	(1)	(1)			(4)	(5)
Interest expense on debt	0	0			0	0
Other expenses	269	308			863	1,006
Total expenses	506	600			1,625	1,926
Provision for income tax expense (benefit)	19	22			55	78
Adjusted earnings	60	94			176	259
MetLife Holdings | Operating Segments [Member]
Revenues
Premiums	745	805			2,281	2,471
Universal life and investment-type product policy fees	232	279			840	826
Net investment income	1,118	1,771			3,807	4,960
Other revenues	39	57			106	188
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	2,134	2,912			7,034	8,445
Expenses
Policyholder benefits and claims and policyholder dividends	1,659	1,611			4,610	4,683
Interest credited to policyholder account balances	202	212			607	632
Capitalization of DAC	(6)	(8)			(21)	(25)
Amortization of DAC and VOBA	(20)	80			130	190
Amortization of negative VOBA	0	0			0	0
Interest expense on debt	2	1			5	4
Other expenses	228	255			706	752
Total expenses	2,065	2,151			6,037	6,236
Provision for income tax expense (benefit)	10	155			197	449
Adjusted earnings	59	606			800	1,760
Corporate & Other | Operating Segments [Member]
Revenues
Premiums	(7)	16			(17)	54
Universal life and investment-type product policy fees	(1)	0			1	1
Net investment income	63	93			172	153
Other revenues	96	108			295	303
Net investment gains (losses)	0	0			0	0
Net derivative gains (losses)	0	0			0	0
Total revenues	151	217			451	511
Expenses
Policyholder benefits and claims and policyholder dividends	(3)	9			(12)	36
Interest credited to policyholder account balances	0	0			0	0
Capitalization of DAC	(2)	(3)			(7)	(9)
Amortization of DAC and VOBA	3	2			7	7
Amortization of negative VOBA	0	0			0	0
Interest expense on debt	231	236			669	683
Other expenses	186	137			506	278
Total expenses	415	381			1,163	995
Provision for income tax expense (benefit)	(63)	(96)			(243)	(288)
Adjusted earnings	$ (201)	$ (68)			$ (469)	$ (196)