Future Policy Benefits - Transition Tables (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	$ 196,406	$ 187,222		$ 224,358
Removal of additional insurance liabilities for separate presentation					$ (6,565)
Subtotal - pre-adoption balance, excluding additional liabilities					200,091
FPB Removal of related amounts in accumulated other comprehensive income				(7,911)
Reclassification of carrying amount of contracts and contract features that are market risk benefits				(176)
FPB traditional and limited-payment contracts				214,694
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				719
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				(7,490)
Removal of remeasured deferred profit liabilities for separate presentation				(4,658)
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				34,119
Balance, deferred profit liabilities at January 1, 2021				4,658
Ceded Recoverables on traditional and limited-payment contracts				1,684
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				351
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				32
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				14
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance				5,006	6,565
Ceded recoverables on additional insurance liabilities				720	727
Ceded Recoverable Reclassification of carrying amount of contracts and contract features that are reinsured market risk benefits				(8)
Ceded Recoverable Adjustments for the cumulative effect of adoption on ceded recoverables on additional insurance liabilities				1
Additional Insurance Liabilities Reclassification of carrying amount of contracts and contract features that are market risk benefits				(1,642)
Additional Insurance Liabilities Adjustments for the cumulative effect of adoption on additional insurance liabilities				83
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					206,656
Ceded Recoverables on traditional and limited-payment contracts					1,287
Fixed & Immediate Annuities | Retirement and Income Solutions
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	64,324	58,495	$ 63,681
Removal of additional insurance liabilities for separate presentation					(4)
Subtotal - pre-adoption balance, excluding additional liabilities					66,026
FPB Removal of related amounts in accumulated other comprehensive income				(5,914)
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				65,970
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				337
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				(7,416)
Removal of remeasured deferred profit liabilities for separate presentation				(2,897)
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				15,834
Balance, deferred profit liabilities at January 1, 2021				2,897
Ceded Recoverables on traditional and limited-payment contracts				344
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				135
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				0
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				6
Fixed & Immediate Annuities | Retirement and Income Solutions | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					66,030
Ceded Recoverables on traditional and limited-payment contracts					203
Whole and Term Life & Endowments | Asia
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	12,874	12,792	18,472
Removal of additional insurance liabilities for separate presentation					0
Subtotal - pre-adoption balance, excluding additional liabilities					17,990
FPB Removal of related amounts in accumulated other comprehensive income				0
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				22,206
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				51
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				4
Removal of remeasured deferred profit liabilities for separate presentation				(225)
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				4,386
Balance, deferred profit liabilities at January 1, 2021				225
Ceded Recoverables on traditional and limited-payment contracts				(15)
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				(15)
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				0
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				0
Whole and Term Life & Endowments | Asia | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					17,990
Ceded Recoverables on traditional and limited-payment contracts					0
Accident & health insurance | Asia
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	10,712	10,040	15,399
Removal of additional insurance liabilities for separate presentation					0
Subtotal - pre-adoption balance, excluding additional liabilities					16,330
FPB Removal of related amounts in accumulated other comprehensive income				0
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				16,125
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				154
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				47
Removal of remeasured deferred profit liabilities for separate presentation				(691)
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				285
Balance, deferred profit liabilities at January 1, 2021				691
Ceded Recoverables on traditional and limited-payment contracts				(36)
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				(66)
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				0
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				(2)
Accident & health insurance | Asia | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					16,330
Ceded Recoverables on traditional and limited-payment contracts					32
Fixed Annuity | Latin America
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	9,637	9,265	7,343
Removal of additional insurance liabilities for separate presentation					0
Subtotal - pre-adoption balance, excluding additional liabilities					8,393
FPB Removal of related amounts in accumulated other comprehensive income				(295)
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				10,517
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				121
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				(1)
Removal of remeasured deferred profit liabilities for separate presentation				(570)
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				2,869
Balance, deferred profit liabilities at January 1, 2021				570
Ceded Recoverables on traditional and limited-payment contracts				0
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				0
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				0
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				0
Fixed Annuity | Latin America | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					8,393
Ceded Recoverables on traditional and limited-payment contracts					0
Long-term Care | MetLife Holdings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	15,240	13,845	20,569
Removal of additional insurance liabilities for separate presentation					0
Subtotal - pre-adoption balance, excluding additional liabilities					14,281
FPB Removal of related amounts in accumulated other comprehensive income				(1,210)
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				21,341
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				0
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				0
Removal of remeasured deferred profit liabilities for separate presentation				0
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				8,270
Balance, deferred profit liabilities at January 1, 2021				0
Ceded Recoverables on traditional and limited-payment contracts				0
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				0
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				0
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				0
Long-term Care | MetLife Holdings | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					14,281
Ceded Recoverables on traditional and limited-payment contracts					0
Participating Life Insurance Contract | MetLife Holdings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	49,543	50,371
Removal of additional insurance liabilities for separate presentation					0
Subtotal - pre-adoption balance, excluding additional liabilities					51,148
FPB Removal of related amounts in accumulated other comprehensive income				0
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				51,148
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				0
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				0
Removal of remeasured deferred profit liabilities for separate presentation				0
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				0
Balance, deferred profit liabilities at January 1, 2021				0
Participating Life Insurance Contract | MetLife Holdings | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					51,148
Long-Duration Insurance, Other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	11,099	10,101
Removal of additional insurance liabilities for separate presentation					(6,561)
Subtotal - pre-adoption balance, excluding additional liabilities					12,567
FPB Removal of related amounts in accumulated other comprehensive income				(492)
Reclassification of carrying amount of contracts and contract features that are market risk benefits				(176)
FPB traditional and limited-payment contracts				14,031
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				56
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				(124)
Removal of remeasured deferred profit liabilities for separate presentation				(275)
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				2,475
Balance, deferred profit liabilities at January 1, 2021				275
Ceded Recoverables on traditional and limited-payment contracts				1,391
Effect of remeasurement of the ceded recoverable to an upper-medium grade discount rate				297
Adjustments for loss contracts (with net premiums in excess of gross premiums) under the modified retrospective approach				32
Adjustments for the cumulative effect of adoption on ceded recoverables on traditional and limited-payment contract				10
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance				380	1,977
Ceded recoverables on additional insurance liabilities				0	8
Ceded Recoverable Reclassification of carrying amount of contracts and contract features that are reinsured market risk benefits				(8)
Ceded Recoverable Adjustments for the cumulative effect of adoption on ceded recoverables on additional insurance liabilities				0
Additional Insurance Liabilities Reclassification of carrying amount of contracts and contract features that are market risk benefits				(1,642)
Additional Insurance Liabilities Adjustments for the cumulative effect of adoption on additional insurance liabilities				45
Long-Duration Insurance, Other | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					19,128
Ceded Recoverables on traditional and limited-payment contracts					1,052
Short-Duration Insurance, Other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	13,190	13,164
Removal of additional insurance liabilities for separate presentation					0
Subtotal - pre-adoption balance, excluding additional liabilities					13,356
FPB Removal of related amounts in accumulated other comprehensive income				0
Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
FPB traditional and limited-payment contracts				13,356
Adjustment of future policy benefits to remeasure cohorts where net premiums exceed gross premiums under the modified retrospective approach				0
Other balance sheet reclassifications and adjustments upon adoption of the LDTI standard				0
Removal of remeasured deferred profit liabilities for separate presentation				0
Effect of remeasurement of future policy benefits to an upper-medium grade discount rate				0
Balance, deferred profit liabilities at January 1, 2021				0
Short-Duration Insurance, Other | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits					13,356
Variable Life | Asia
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	1,258	1,381
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance	1,258	1,381	1,595	1,824	1,824
Ceded recoverables on additional insurance liabilities				0	0
Ceded Recoverable Reclassification of carrying amount of contracts and contract features that are reinsured market risk benefits				0
Ceded Recoverable Adjustments for the cumulative effect of adoption on ceded recoverables on additional insurance liabilities				0
Additional Insurance Liabilities Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
Additional Insurance Liabilities Adjustments for the cumulative effect of adoption on additional insurance liabilities				0
Universal and Variable Universal Life | Asia
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	424	455
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance	424	455	655	788	788
Ceded recoverables on additional insurance liabilities				0	0
Ceded Recoverable Reclassification of carrying amount of contracts and contract features that are reinsured market risk benefits				0
Ceded Recoverable Adjustments for the cumulative effect of adoption on ceded recoverables on additional insurance liabilities				0
Additional Insurance Liabilities Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
Additional Insurance Liabilities Adjustments for the cumulative effect of adoption on additional insurance liabilities				0
Universal and Variable Universal Life | MetLife Holdings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	2,362	2,156
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance	$ 2,362	$ 2,156	$ 2,117	2,014	1,976
Ceded recoverables on additional insurance liabilities				720	$ 719
Ceded Recoverable Reclassification of carrying amount of contracts and contract features that are reinsured market risk benefits				0
Ceded Recoverable Adjustments for the cumulative effect of adoption on ceded recoverables on additional insurance liabilities				1
Additional Insurance Liabilities Reclassification of carrying amount of contracts and contract features that are market risk benefits				0
Additional Insurance Liabilities Adjustments for the cumulative effect of adoption on additional insurance liabilities				$ 38