Mortgage Servicing Rights Liability Resulting from Sale or Securitization of Servicer Advances, Rights not Accounted for as a Sale

No definition available.

+ Details

Name:	nsm_MortgageServicingRightsLiabilityResultingfromSaleofServicerAdvancesRightsnotAccountedforasaSale
Namespace Prefix:	nsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

+ Details

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

- Definition

This is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107314-111719

+ Details

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

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=nsm_ForwardMSRsSoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=nsm_ForwardMSRsSoldSubservicingRetainedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=nsm_ReverseMortgageServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nsm_HECMMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Mortgage Servicing Rights and Related Liabilities - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Servicing Asset at Amortized Cost [Line Items]
Mortgage servicing rights financing - fair value	$ 47,000,000	$ 37,000,000
Forward MSRs Sold
Servicing Asset at Amortized Cost [Line Items]
UPB	94,000,000		$ 25,639,000,000
Forward MSRs Sold, Subservicing Retained
Servicing Asset at Amortized Cost [Line Items]
UPB	0		$ 20,560,000,000
Reverse Mortgage Servicing Rights
Servicing Asset at Amortized Cost [Line Items]
Impairment	0
HECM
Servicing Asset at Amortized Cost [Line Items]
UPB	$ 20,006,000,000	$ 22,725,000,000