Future Policy Benefits - Disaggregate Rollforwards (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jan. 01, 2021
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for future policy benefits	$ 181,755		$ 187,222	$ 224,358
Fixed & Immediate Annuities | U.S.
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period, at current discount rate at balance sheet date	0	$ 0
Balance, beginning of period, at original discount rate	0	0
Effect of changes in cash flow assumptions (1)	0	0
Effect of actual variances from expected experience (2)	(89)	(15)
Adjusted balance	(89)	(15)
Issuances	4,422	12,500
Net premiums collected	(4,333)	(12,485)
Ending balance at original discount rate	0	0
Balance, end of period, at current discount rate at balance sheet date	0	0
Balance, beginning of period, at current discount rate at balance sheet date	58,695	62,954
Balance, beginning of period, at original discount rate	61,426	50,890
Effect of changes in cash flow assumptions (1)	(284)	(115)
Effect of actual variances from expected experience (2)	(222)	(82)
Adjusted balance	60,920	50,693
Issuances	4,420	12,598
Interest accrual	2,145	1,811
Benefit payments	(4,121)	(3,322)
Ending balance at original discount rate	63,364	61,780
Effect of changes in discount rate assumptions	(5,438)	(4,382)
Balance, end of period, at current discount rate at balance sheet date	57,926	57,398
Cumulative amount of fair value hedging adjustments	(430)	(169)
Net liability for future policy benefits	57,496	57,229	58,495
Less: Reinsurance recoverables	0	0
Net liability for future policy benefits, net of reinsurance	57,496	57,229
Undiscounted - Expected future benefit payments	119,270	114,766
Discounted - Expected future benefit payments (at current discount rate at balance sheet date)	$ 57,926	$ 57,398
Weighted-average duration of the liability	9 years	9 years
Weighted-average interest accretion (original locked-in) rate	4.70%	4.40%
Weighted-average current discount rate at balance sheet date	6.10%	5.80%
Deferred Profit Liability Offset to Cash Flow Assumption Update	$ 211	$ 128
Deferred Profit Liability Offset to Actual Versus Expected	95	40
Whole and Term Life & Endowments | Asia
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period, at current discount rate at balance sheet date	4,682	5,986
Balance, beginning of period, at original discount rate	4,943	5,881
Effect of changes in cash flow assumptions (1)	11	71
Effect of actual variances from expected experience (2)	(41)	35
Adjusted balance	4,913	5,987
Issuances	614	146
Interest accrual	43	33
Net premiums collected	(457)	(469)
Effect of foreign currency translation	(518)	(1,109)
Ending balance at original discount rate	4,595	4,588
Effect of changes in discount rate assumptions	(319)	(160)
Effect of foreign currency translation on the effect of changes in discount rate assumptions	23	5
Balance, end of period, at current discount rate at balance sheet date	4,299	4,433
Balance, beginning of period, at current discount rate at balance sheet date	17,463	24,453
Balance, beginning of period, at original discount rate	18,209	21,276
Effect of changes in cash flow assumptions (1)	58	97
Effect of actual variances from expected experience (2)	(14)	50
Adjusted balance	18,253	21,423
Issuances	614	146
Interest accrual	278	277
Benefit payments	(895)	(1,088)
Effect of foreign currency translation	(1,847)	(4,071)
Ending balance at original discount rate	16,403	16,687
Effect of changes in discount rate assumptions	(742)	(74)
Effect of foreign currency translation on the effect of changes in discount rate assumptions	40	(228)
Balance, end of period, at current discount rate at balance sheet date	15,701	16,385
Cumulative amount of fair value hedging adjustments	2	30
Net liability for future policy benefits	11,404	11,982	12,792
Less: Reinsurance recoverables	(1)	0
Net liability for future policy benefits, net of reinsurance	11,405	11,982
Undiscounted - Expected future gross premiums	8,911	8,888
Undiscounted - Expected future benefit payments	26,785	25,565
Discounted - Expected future gross premiums	7,582	7,796
Discounted - Expected future benefit payments (at current discount rate at balance sheet date)	$ 15,701	$ 16,385
Weighted-average duration of the liability	17 years	16 years
Weighted-average interest accretion (original locked-in) rate	2.50%	2.40%
Weighted-average current discount rate at balance sheet date	2.90%	2.50%
Accident and Health Insurance Product Line | Asia
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period, at current discount rate at balance sheet date	$ 21,181	$ 26,543
Balance, beginning of period, at original discount rate	22,594	25,937
Effect of changes in cash flow assumptions (1)	867	24
Effect of actual variances from expected experience (2)	(75)	298
Adjusted balance	23,386	26,259
Issuances	813	1,149
Interest accrual	179	192
Net premiums collected	(1,546)	(1,659)
Effect of foreign currency translation	(2,474)	(5,180)
Ending balance at original discount rate	20,358	20,761
Effect of changes in discount rate assumptions	(1,803)	(886)
Effect of foreign currency translation on the effect of changes in discount rate assumptions	136	45
Balance, end of period, at current discount rate at balance sheet date	18,691	19,920
Balance, beginning of period, at current discount rate at balance sheet date	30,879	41,874
Balance, beginning of period, at original discount rate	37,189	41,517
Effect of changes in cash flow assumptions (1)	898	(7)
Effect of actual variances from expected experience (2)	(99)	354
Adjusted balance	37,988	41,864
Issuances	812	1,150
Interest accrual	367	381
Benefit payments	(958)	(1,242)
Effect of foreign currency translation	(4,061)	(8,327)
Ending balance at original discount rate	34,148	33,826
Effect of changes in discount rate assumptions	(6,866)	(5,168)
Effect of foreign currency translation on the effect of changes in discount rate assumptions	595	535
Balance, end of period, at current discount rate at balance sheet date	27,877	29,193
Cumulative amount of fair value hedging adjustments	143	247
Net liability for future policy benefits	9,329	9,520	10,040
Less: Reinsurance recoverables	136	16
Net liability for future policy benefits, net of reinsurance	9,193	9,504
Undiscounted - Expected future gross premiums	39,891	39,847
Undiscounted - Expected future benefit payments	44,612	43,770
Discounted - Expected future gross premiums	32,286	34,046
Discounted - Expected future benefit payments (at current discount rate at balance sheet date)	$ 27,877	$ 29,193
Weighted-average duration of the liability	25 years	20 years
Weighted-average interest accretion (original locked-in) rate	1.80%	1.80%
Weighted-average current discount rate at balance sheet date	2.80%	2.40%
Fixed Annuity | Latin America
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period, at current discount rate at balance sheet date	$ 0	$ 0
Balance, beginning of period, at original discount rate	0	0
Effect of changes in cash flow assumptions (1)	0	0
Effect of actual variances from expected experience (2)	(2)	1
Adjusted balance	(2)	1
Issuances	785	551
Interest accrual	16	(3)
Net premiums collected	(799)	(549)
Ending balance at original discount rate	0	0
Balance, end of period, at current discount rate at balance sheet date	0	0
Balance, beginning of period, at current discount rate at balance sheet date	9,265	7,343
Balance, beginning of period, at original discount rate	8,240	6,851
Effect of changes in cash flow assumptions (1)	(5)	(11)
Effect of actual variances from expected experience (2)	(13)	(26)
Adjusted balance	8,222	6,814
Issuances	869	590
Interest accrual	258	213
Benefit payments	(504)	(422)
Inflation adjustment	273	713
Effect of foreign currency translation	(403)	(821)
Ending balance at original discount rate	8,715	7,087
Effect of changes in discount rate assumptions	(59)	394
Effect of foreign currency translation on the effect of changes in discount rate assumptions	6	(87)
Balance, end of period, at current discount rate at balance sheet date	8,662	7,394
Net liability for future policy benefits	8,662	7,394	9,265
Undiscounted - Expected future benefit payments	13,204	10,931
Discounted - Expected future benefit payments (at current discount rate at balance sheet date)	$ 8,662	$ 7,394
Weighted-average duration of the liability	10 years	11 years
Weighted-average interest accretion (original locked-in) rate	3.90%	4.20%
Weighted-average current discount rate at balance sheet date	3.70%	3.40%
Deferred Profit Liability Offset to Cash Flow Assumption Update	$ 4	$ 10
Deferred Profit Liability Offset to Actual Versus Expected	2	17
Long-term Care | MetLife Holdings
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period, at current discount rate at balance sheet date	5,775	7,058
Balance, beginning of period, at original discount rate	5,807	5,699
Effect of changes in cash flow assumptions (1)	(152)	272
Effect of actual variances from expected experience (2)	173	101
Adjusted balance	5,828	6,072
Interest accrual	222	223
Net premiums collected	(438)	(434)
Ending balance at original discount rate	5,612	5,861
Effect of changes in discount rate assumptions	(258)	(142)
Balance, end of period, at current discount rate at balance sheet date	5,354	5,719
Balance, beginning of period, at current discount rate at balance sheet date	19,619	27,627
Balance, beginning of period, at original discount rate	20,165	19,406
Effect of changes in cash flow assumptions (1)	(190)	301
Effect of actual variances from expected experience (2)	194	100
Adjusted balance	20,169	19,807
Interest accrual	801	778
Benefit payments	(579)	(522)
Ending balance at original discount rate	20,391	20,063
Effect of changes in discount rate assumptions	(2,012)	(1,358)
Balance, end of period, at current discount rate at balance sheet date	18,379	18,705
Net liability for future policy benefits	13,025	12,986	$ 13,845
Undiscounted - Expected future gross premiums	10,713	11,335
Undiscounted - Expected future benefit payments	45,152	46,011
Discounted - Expected future gross premiums	6,714	7,126
Discounted - Expected future benefit payments (at current discount rate at balance sheet date)	$ 18,379	$ 18,705
Weighted-average duration of the liability	14 years	15 years
Weighted-average interest accretion (original locked-in) rate	5.50%	5.50%
Weighted-average current discount rate at balance sheet date	6.30%	6.00%