Mortgage Servicing Rights [Line Items]

No definition available.

Name:	coop_MortgageServicingRightsLineItems
Namespace Prefix:	coop_
Data Type:	xbrli:stringItemType
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Period Type:	duration

Reverse Mortgage Interest, Unpaid Principal Balance, Unsecuritized

No definition available.

Name:	coop_ReverseMortgageInterestUnpaidPrincipalBalanceUnsecuritized
Namespace Prefix:	coop_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Reverse Mortgage Interest, Unpaid Principal Balance, Unsecuritized, Funded Draws Not Yet Securitized

No definition available.

Name:	coop_ReverseMortgageInterestUnpaidPrincipalBalanceUnsecuritizedFundedDrawsNotYetSecuritized
Namespace Prefix:	coop_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Reverse Mortgage Interest, Unpaid Principal Balance, Unsecuritized, Home Equity Conversion Mortgage Receivables

No definition available.

Name:	coop_ReverseMortgageInterestUnpaidPrincipalBalanceUnsecuritizedHomeEquityConversionMortgageReceivables
Namespace Prefix:	coop_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Reverse Mortgage Interest, Unpaid Principal Balance, Unsecuritized, Purchase Discount

No definition available.

Name:	coop_ReverseMortgageInterestUnpaidPrincipalBalanceUnsecuritizedPurchaseDiscount
Namespace Prefix:	coop_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Reverse Mortgage Interest, Unpaid Principal Balance, Unsecuritized, Real Estate Owned Related Receivables

No definition available.

Name:	coop_ReverseMortgageInterestUnpaidPrincipalBalanceUnsecuritizedRealEstateOwnedRelatedReceivables
Namespace Prefix:	coop_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Reverse Mortgage Interest, Unpaid Principal Balance, Unsecuritized, Repurchase of Home Equity Conversion Mortgages

No definition available.

Name:	coop_ReverseMortgageInterestUnpaidPrincipalBalanceUnsecuritizedRepurchaseofHomeEquityConversionMortgages
Namespace Prefix:	coop_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Reverse Mortgage Interests, Net - Unsecuritized Interest (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jul. 31, 2018	Dec. 31, 2017
Mortgage Servicing Rights [Line Items]
Repurchased HECM loans	$ 1,512
HECM related receivables	353
Funded borrower draws not yet securitized	68
REO related receivables	28
Purchase discount	(151)	$ (161)
Total unsecuritized interests	$ 1,810
Predecessor
Mortgage Servicing Rights [Line Items]
Repurchased HECM loans			$ 1,751
HECM related receivables			311
Funded borrower draws not yet securitized			82
REO related receivables			25
Purchase discount			(89)
Total unsecuritized interests			$ 2,080