Future Policy Benefits - FPB - Additional Insurance Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 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 changes in cash flow assumptions	17	(4)
Effect of actual variances from expected experience	(8)	(9)
Adjusted balance	1,267	1,368
Assessments accrual	(3)	(3)
Interest accrual	13	15
Excess benefits paid	(30)	(29)
Effect of foreign currency translation and other, net	(20)	(158)
Balance, end of period, before AOCI adjustment	1,227	1,193
Add: AOCI adjustment	0	0
Balance, end of period	$ 1,227	$ 1,193
Weighted-average duration of the liability	16 years	16 years
Weighted-average interest accretion rate	1.40%	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 changes in cash flow assumptions	(23)	(2)
Effect of actual variances from expected experience	(14)	(32)
Adjusted balance	401	454
Assessments accrual	0	0
Interest accrual	4	5
Excess benefits paid	0	0
Effect of foreign currency translation and other, net	(6)	(55)
Balance, end of period, before AOCI adjustment	399	404
Add: AOCI adjustment	0	(18)
Balance, end of period	$ 399	$ 386
Weighted-average duration of the liability	42 years	43 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 changes in cash flow assumptions	(2)	38
Effect of actual variances from expected experience	36	(10)
Adjusted balance	2,410	2,247
Assessments accrual	78	80
Interest accrual	98	92
Excess benefits paid	(104)	(81)
Balance, end of period, before AOCI adjustment	2,482	2,338
Add: AOCI adjustment	(11)	(65)
Balance, end of period	2,471	2,273
Less: Reinsurance recoverables	2,147	766
Balance, end of period, net of reinsurance	$ 324	$ 1,507
Weighted-average duration of the liability	15 years	16 years
Weighted-average interest accretion rate	5.50%	5.50%