MONY CLOSED BLOCK OF BUSINESS - Summary of Financial Information of the Policyholder Dividend Obligation (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Closed block liabilities
Future policy benefits, policyholders’ account balances and other policyholder liabilities	$ 5,313	$ 5,406
Policyholder dividend obligation	406	580	$ 474	$ 279
Other liabilities	14	7
Total closed block liabilities	5,733	5,993
Closed block assets
Fixed maturities, available-for-sale, at fair value	4,720	4,903
Commercial mortgage loans	68	68
Policy loans	571	596
Cash and other invested assets	12	46
Other assets	92	91
Total closed block assets	5,463	5,704
Excess of reported closed block liabilities over closed block assets	270	289
Portion of above representing accumulated other comprehensive income:
Net unrealized gains (losses) - net of policyholder dividend obligation: 2021 - $327 and 2020 - $493; and net of income tax: 2021 - $(69) and 2020 - $(104)	0	0
Future earnings to be recognized from closed block assets and closed block liabilities	270	289
Policyholder dividend obligations	327	493
Income tax expense (benefit)	$ (69)	$ (104)

Represents the amount of cash and other invested assets held by the closed block.

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Amount of unrealized gain (loss) on investments that were allocated to the closed block, net of deferred tax benefits.

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Amount of deferred income tax expense (benefit) pertaining to policyholder dividend obligation.

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Represents the amount of future policy benefits, policyholders' account balances and other to be paid as of the balance sheet date to policyholders of contracts in the closed block.

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The sum of cash, cash equivalents, investments and other assets allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.

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Fair value of investments in debt securities that are deemed to be available for sale that are allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block. Change in fair of such securities is a component of change in other comprehensive income in the period, which is reflected in the closed block disclosure.

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Carrying amount of investments in mortgage loans on real estate allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.

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Amount of other assets held by the closed block. Excludes other investments.

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Carrying amount of loans to policy holders secured by benefits under insurance policies that are allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.

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The carrying amount of closed block liabilities in excess of the carrying amount of closed block assets at the date of demutualization (adjusted to eliminate the impact of related amounts in accumulated other comprehensive income).

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The net increase or decrease in the period in the fair value of the fixed maturity and equity investments designated as available for sale as of the balance sheet date that were allocated to the segregated group of participating or dividend-paying policies and contracts identified as a closed block. Also a component of change in other comprehensive income in the period, which is reflected in the closed block disclosure.

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For the segregated group of participating or dividend-paying policies and contracts along with the assets backing them (known as a closed block), the total of future policy benefits, policyholder account balance, policyholder dividend obligation and any other closed block liabilities.

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Amount of liabilities allocated to the closed block, classified as other.

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The liability as of the balance sheet date for the excess of the cumulative actual closed block earnings over the cumulative expected (actuarially determined) closed block earnings (each) for the period from the actuarial calculation date to the date of measurement. The excess will result in future dividends to closed block policyholders, unless offset by less favorable than expected future performance of the closed block. The policyholder dividend obligation, which may not have a negative balance, recognizes that a portion of earnings in certain cases will not inure to the stockholders of the insurance entity.

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The difference between the liabilities of and the assets allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.

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