Employee Stock Ownership Plan Qualifying Age

No definition available.

Name:	nycb_EmployeeStockOwnershipPlanQualifyingAge
Namespace Prefix:	nycb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after tax, of expense for award under share-based payment arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of common stock held in a trust that has been set up specifically to accumulate stock for the sole purpose of distribution to participating employees but not yet earned.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 25
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=109244457&loc=d3e16701-113920

+ Details

Name:	us-gaap_CommonStockSharesHeldInEmployeeTrustShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of plan compensation cost recognized during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109244661&loc=d3e17540-113929

+ Details

Name:	us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The shares or units in an ESOP trust that have been assigned to individual participant accounts based on a known formula. IRS rules require allocations to be nondiscriminatory generally based on compensation, length of service, or a combination of both. For any particular participant such shares or units may be vested, unvested, or partially vested.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109244661&loc=d3e17540-113929

+ Details

Name:	us-gaap_EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the plan, including the basis for determining contributions, the employee groups covered, and the nature and effect of significant matters affecting comparability of information for all periods presented. For leveraged ESOPs and pension reversion ESOPs, the description generally includes the basis for releasing shares and how dividends on allocated and unallocated shares are used.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109244661&loc=d3e17540-113929

+ Details

Name:	us-gaap_EmployeeStockOwnershipPlanESOPPlanDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of service or performance condition required to be met for earning right to award under share-based payment arrangement. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of vesting of award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=nycb_PerformanceBasedRestrictedStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=nycb_StockIncentivePlanTwentyTwelveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=nycb_SupplementalExecutiveRetirementPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=nycb_NewYorkCommunityBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=us-gaap_ShareBasedCompensationAwardTrancheOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=us-gaap_ShareBasedCompensationAwardTrancheTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Related Benefit Plans - Additional Information (Details) $ / shares in Units, $ in Millions	12 Months Ended			24 Months Ended
	Dec. 31, 2020 USD ($) Age $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	11,913,461			11,913,461
Shares granted	2,421,345
Shares granted, weighted average grant date fair value \| $ / shares	$ 11.61
Unrecognized compensation cost relating to unvested restricted stock \| $	$ 52.5			$ 52.5
Unrecognized compensation cost relating to unvested restricted stock, recognition period (in years)	2 years 9 months 18 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, vesting period	5 years
Shares granted	2,421,345
Shares granted, weighted average grant date fair value \| $ / shares	$ 11.61
Compensation and benefits expense \| $	$ 28.4	$ 30.9	$ 36.3
Forfeited shares	528,507
Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted	446,181	418,674		477,872
Unrecognized compensation cost relating to unvested restricted stock \| $	$ 3.1			$ 3.1
Unrecognized compensation cost relating to unvested restricted stock, recognition period (in years)	1 year 9 months 18 days
Vesting rights, description	Included in this total are 446,181 shares granted during the twelve months ended December 31, 2020, which have a performance period of January 1, 2020 to December 31, 2022 and vest on April 1, 2023, subject to adjustment or forfeiture, based upon the achievement by the Company of certain performance standards. During the twelve months ended December 31, 2020, 386,983 shares were forfeited. The Company granted 418,674 PSUs during 2019, which have a performance period of January 1, 2019 to December 31, 2021 and vest on April 1, 2022, subject to adjustment or forfeiture, based upon the achievement by the Company of certain performance standards.
Compensation and benefits expense \| $	$ 1.0	$ 1.1
Forfeited shares	386,983
Stock Incentive Plan Twenty Twelve \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		2,031,198	2,543,023
Shares granted, weighted average grant date fair value \| $ / shares		$ 10.45	$ 13.50
Supplemental Executive Retirement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Trust held assets of Supplemental Executive Retirement Plan (SERP), shares	2,191,915	2,046,449		2,191,915
New York Community Bank
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Full-time employees, age to participate in plan \| Age	21
Description of the ESOP Plan	All full-time employees who have attained 21 years of age and have completed twelve consecutive months of credited service are eligible to participate in the ESOP, with benefits vesting on a six-year basis
Shares granted, vesting period	6 years
Allocated shares to participants in the ESOP	405,167	349,356	529,531	405,167
ESOP-related compensation expense \| $	$ 4.3	$ 4.2	$ 5.0
New York Community Bank \| Third year of employment
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares vested	20.00%
New York Community Bank \| Each successive year after third year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares vested	20.00%