Unsecured Debt, Gross

No definition available.

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

Name:	us-gaap_UnsecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=nsm_UnsecuredSeniorNotes8.125DueJuly2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nsm_UnsecuredSeniorNotes9.125DueJuly2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nsm_UnsecuredSeniorNotesSixPointFivePercentDueJuly2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=nsm_UnsecuredSeniorNotesSixPointFivePercentDueJuly2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Indebtedness - Unsecured Senior Notes (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Jul. 13, 2018
Debt Instrument [Line Items]
Debt issuance costs	$ (10,000,000)	$ (68,000,000)
Unsecured senior notes, net	2,366,000,000	2,459,000,000
$950 face value, 8.125% interest rate payable semi-annually, due July 2023
Debt Instrument [Line Items]
Face amount			$ 950,000,000
Interest rate			8.125%
$750 face value, 9.125% interest rate payable semi-annually, due July 2026
Debt Instrument [Line Items]
Face amount			$ 750,000,000
Interest rate			9.125%
Unsecured Senior Notes
Debt Instrument [Line Items]
Unsecured senior notes principal amount	2,398,000,000	2,498,000,000
Debt issuance costs	(32,000,000)	(39,000,000)
Unsecured senior notes, net	2,366,000,000	2,459,000,000
Face amount	2,398,000,000
Unsecured Senior Notes \| $950 face value, 8.125% interest rate payable semi-annually, due July 2023
Debt Instrument [Line Items]
Unsecured senior notes principal amount	950,000,000	950,000,000
Face amount	$ 950,000,000
Interest rate	8.125%
Unsecured Senior Notes \| $750 face value, 9.125% interest rate payable semi-annually, due July 2026
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 750,000,000	750,000,000
Face amount	$ 750,000,000
Interest rate	9.125%
Unsecured Senior Notes \| $600 face value, 6.500% interest rate payable semi-annually, due July 2021
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 492,000,000	592,000,000
Face amount	$ 600,000,000
Interest rate	6.50%
Unsecured Senior Notes \| $300 face value, 6.500% interest rate payable semi-annually, due June 2022
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 206,000,000	$ 206,000,000
Face amount	$ 300,000,000
Interest rate	6.50%