Future Policy Benefits -Transition Tables (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 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	$ 181,755	$ 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 | U.S.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	57,496	58,495	$ 57,229
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 | U.S. | 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	11,404	12,792	11,982
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 and Health Insurance Product Line | Asia
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	9,329	10,040	9,520
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 and Health Insurance Product Line | 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	8,662	9,265	7,394
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	13,025	13,845	12,986
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	49,717	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	9,676	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	13,047	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	1,193	1,381
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance	1,193	1,381	1,264	$ 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 Life Contracts [Member] | Asia
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	386	455
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance	386	455	402	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 Life Contracts [Member] | MetLife Holdings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net liability for future policy benefits	2,273	2,156
Additional Liability, Long-Duration Insurance, Original Discount Rate, before Cash Flow and Reinsurance	$ 2,273	$ 2,156	$ 2,119	$ 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