Future Policy Benefits - FPB - Additional Insurance Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Variable Life | Asia
Additional Liability, Long-Duration Insurance [Roll Forward]
Balance, beginning of period	$ 1,258	$ 1,381
Less: AOCI adjustment	0	0
Balance, beginning of period, before AOCI adjustment	1,258	1,381
Effect of actual variances from expected experience	(13)	(2)
Adjusted balance	1,245	1,379
Assessments accrual	(1)	(1)
Interest accrual	4	5
Excess benefits paid	(9)	(10)
Effect of foreign currency translation and other, net	(86)	(11)
Balance, end of period, before AOCI adjustment	1,153	1,362
Add: AOCI adjustment	0	0
Balance, end of period	$ 1,153	$ 1,362
Weighted-average duration of the liability	16 years	17 years
Weighted-average interest accretion rate	1.50%	1.50%
Universal and Variable Universal Life | Asia
Additional Liability, Long-Duration Insurance [Roll Forward]
Balance, beginning of period	$ 424	$ 455
Less: AOCI adjustment	(14)	(33)
Balance, beginning of period, before AOCI adjustment	438	488
Effect of actual variances from expected experience	(17)	(3)
Adjusted balance	421	485
Assessments accrual	0	(1)
Interest accrual	1	2
Excess benefits paid	0	0
Effect of foreign currency translation and other, net	(30)	(5)
Balance, end of period, before AOCI adjustment	392	481
Add: AOCI adjustment	(7)	(23)
Balance, end of period	$ 385	$ 458
Weighted-average duration of the liability	43 years	42 years
Weighted-average interest accretion rate	1.40%	1.50%
Universal and Variable Universal Life | MetLife Holdings
Additional Liability, Long-Duration Insurance [Roll Forward]
Balance, beginning of period	$ 2,362	$ 2,156
Less: AOCI adjustment	(14)	(63)
Balance, beginning of period, before AOCI adjustment	2,376	2,219
Effect of actual variances from expected experience	14	11
Adjusted balance	2,390	2,230
Assessments accrual	26	28
Interest accrual	32	30
Excess benefits paid	(37)	(40)
Balance, end of period, before AOCI adjustment	2,411	2,248
Add: AOCI adjustment	(15)	(50)
Balance, end of period	2,396	2,198
Less: Reinsurance recoverables	2,086	748
Balance, end of period, net of reinsurance	$ 310	$ 1,450
Weighted-average duration of the liability	15 years	16 years
Weighted-average interest accretion rate	5.50%	5.60%