Guarantor Financial Statement Information - Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Aug. 01, 2018	Jul. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 329	$ 242		$ 166	$ 215
Restricted cash	283	319		430	360
Mortgage servicing rights	3,502	3,676
Advances and other receivables, net	988	1,194
Reverse mortgage interests, net	6,279	7,934
Mortgage loans held for sale at fair value	4,077	1,631
Mortgage loans held for investment, net	0	119
Property and equipment, net	112	96
Deferred tax assets, net	1,345	967
Other assets	1,390	795
Investment in subsidiaries	0	0
Total assets	18,305	16,973		17,026	18,036
Liabilities and Stockholders’ Equity
Unsecured senior notes, net	2,366	2,459
Advance facilities, net	422	595
Warehouse facilities, net	4,575	2,349
Payables and other liabilities	2,016	1,543
MSR related liabilities - nonrecourse at fair value	1,348	1,216
Mortgage servicing liabilities	61	71
Other nonrecourse debt, net	5,286	6,795
Payables to affiliates	0	0
Total liabilities	16,074	15,028
Total stockholders’ equity	2,231	1,945	$ 1,056	$ 1,883	$ 1,722	$ 1,683
Total liabilities and stockholders’ equity	18,305	16,973
Reportable legal entities | Mr. Cooper
Assets
Cash and cash equivalents	0	0
Restricted cash	0	0
Mortgage servicing rights	0	0
Advances and other receivables, net	0	0
Reverse mortgage interests, net	0	0
Mortgage loans held for sale at fair value	0	0
Mortgage loans held for investment, net		0
Property and equipment, net	0	0
Deferred tax assets, net	1,273	973
Other assets	0	0
Investment in subsidiaries	2,828	2,820
Total assets	4,101	3,793
Liabilities and Stockholders’ Equity
Unsecured senior notes, net	1,667	1,660
Advance facilities, net	0	0
Warehouse facilities, net	0	0
Payables and other liabilities	63	49
MSR related liabilities - nonrecourse at fair value	0	0
Mortgage servicing liabilities	0	0
Other nonrecourse debt, net	0	0
Payables to affiliates	140	139
Total liabilities	1,870	1,848
Total stockholders’ equity	2,231	1,945
Total liabilities and stockholders’ equity	4,101	3,793
Reportable legal entities | Issuer
Assets
Cash and cash equivalents	287	193
Restricted cash	175	186
Mortgage servicing rights	3,478	3,644
Advances and other receivables, net	988	1,194
Reverse mortgage interests, net	5,312	6,770
Mortgage loans held for sale at fair value	4,077	1,631
Mortgage loans held for investment, net		1
Property and equipment, net	92	84
Deferred tax assets, net	70	0
Other assets	1,279	660
Investment in subsidiaries	698	601
Total assets	16,456	14,964
Liabilities and Stockholders’ Equity
Unsecured senior notes, net	699	799
Advance facilities, net	63	90
Warehouse facilities, net	4,575	2,349
Payables and other liabilities	1,882	1,413
MSR related liabilities - nonrecourse at fair value	1,334	1,197
Mortgage servicing liabilities	61	71
Other nonrecourse debt, net	4,299	5,676
Payables to affiliates	715	549
Total liabilities	13,628	12,144
Total stockholders’ equity	2,828	2,820
Total liabilities and stockholders’ equity	16,456	14,964
Reportable legal entities | Guarantor (Subsidiaries of Issuer)
Assets
Cash and cash equivalents	1	1
Restricted cash	0	0
Mortgage servicing rights	0	0
Advances and other receivables, net	0	0
Reverse mortgage interests, net	0	0
Mortgage loans held for sale at fair value	0	0
Mortgage loans held for investment, net		0
Property and equipment, net	0	0
Deferred tax assets, net	0	0
Other assets	215	202
Investment in subsidiaries	0	0
Total assets	216	203
Liabilities and Stockholders’ Equity
Unsecured senior notes, net	0	0
Advance facilities, net	0	0
Warehouse facilities, net	0	0
Payables and other liabilities	1	1
MSR related liabilities - nonrecourse at fair value	0	0
Mortgage servicing liabilities	0	0
Other nonrecourse debt, net	0	0
Payables to affiliates	0	0
Total liabilities	1	1
Total stockholders’ equity	215	202
Total liabilities and stockholders’ equity	216	203
Reportable legal entities | Non-Guarantor (Subsidiaries of Issuer)
Assets
Cash and cash equivalents	41	48
Restricted cash	108	133
Mortgage servicing rights	24	32
Advances and other receivables, net	0	0
Reverse mortgage interests, net	967	1,164
Mortgage loans held for sale at fair value	0	0
Mortgage loans held for investment, net		118
Property and equipment, net	20	12
Deferred tax assets, net	2	(6)
Other assets	751	621
Investment in subsidiaries	0	0
Total assets	1,913	2,122
Liabilities and Stockholders’ Equity
Unsecured senior notes, net	0	0
Advance facilities, net	359	505
Warehouse facilities, net	0	0
Payables and other liabilities	70	80
MSR related liabilities - nonrecourse at fair value	14	19
Mortgage servicing liabilities	0	0
Other nonrecourse debt, net	987	1,119
Payables to affiliates	0	0
Total liabilities	1,430	1,723
Total stockholders’ equity	483	399
Total liabilities and stockholders’ equity	1,913	2,122
Eliminations
Assets
Cash and cash equivalents	0	0
Restricted cash	0	0
Mortgage servicing rights	0	0
Advances and other receivables, net	0	0
Reverse mortgage interests, net	0	0
Mortgage loans held for sale at fair value	0	0
Mortgage loans held for investment, net		0
Property and equipment, net	0	0
Deferred tax assets, net	0	0
Other assets	(855)	(688)
Investment in subsidiaries	(3,526)	(3,421)
Total assets	(4,381)	(4,109)
Liabilities and Stockholders’ Equity
Unsecured senior notes, net	0	0
Advance facilities, net	0	0
Warehouse facilities, net	0	0
Payables and other liabilities	0	0
MSR related liabilities - nonrecourse at fair value	0	0
Mortgage servicing liabilities	0	0
Other nonrecourse debt, net	0	0
Payables to affiliates	(855)	(688)
Total liabilities	(855)	(688)
Total stockholders’ equity	(3,526)	(3,421)
Total liabilities and stockholders’ equity	$ (4,381)	$ (4,109)