Guarantor Financial Statement Information - Consolidating Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Service related, net	$ 84
Net gain on mortgage loans held for sale	166
Total revenues	250
Expenses:
Salaries, wages and benefits	215
General and administrative	228
Total expenses	443
Other income (expenses):
Interest income	134
Interest expense	(189)
Other income (expenses)	15
Gain (loss) from subsidiaries	0
Total other income (expenses), net	(40)
(Loss) income before income tax expense (benefit)	(233)
Less: Income tax (benefit) expense	47
Net (loss) income	(186)
Less: Net (loss) income attributable to non-controlling interests	0
Net (loss) income attributable to Successor/Predecessor	(186)
Predecessor
Revenues:
Service related, net		$ 464
Net gain on mortgage loans held for sale		124
Total revenues		588
Expenses:
Salaries, wages and benefits		180
General and administrative		184
Total expenses		364
Other income (expenses):
Interest income		145
Interest expense		(171)
Other income (expenses)		8
Gain (loss) from subsidiaries		0
Total other income (expenses), net		(18)
(Loss) income before income tax expense (benefit)		206
Less: Income tax (benefit) expense		(46)
Net (loss) income		160
Less: Net (loss) income attributable to non-controlling interests		0
Net (loss) income attributable to Successor/Predecessor		160
Eliminations
Revenues:
Service related, net	0
Net gain on mortgage loans held for sale	0
Total revenues	0
Expenses:
Salaries, wages and benefits	0
General and administrative	0
Total expenses	0
Other income (expenses):
Interest income	0
Interest expense	0
Other income (expenses)	0
Gain (loss) from subsidiaries	139
Total other income (expenses), net	139
(Loss) income before income tax expense (benefit)	139
Less: Income tax (benefit) expense	0
Net (loss) income	139
Less: Net (loss) income attributable to non-controlling interests	0
Net (loss) income attributable to Successor/Predecessor	139
Eliminations | Predecessor
Revenues:
Service related, net		0
Net gain on mortgage loans held for sale		0
Total revenues		0
Expenses:
Salaries, wages and benefits		0
General and administrative		0
Total expenses		0
Other income (expenses):
Interest income		0
Interest expense		0
Other income (expenses)		0
Gain (loss) from subsidiaries		(192)
Total other income (expenses), net		(192)
(Loss) income before income tax expense (benefit)		(192)
Less: Income tax (benefit) expense		0
Net (loss) income		(192)
Less: Net (loss) income attributable to non-controlling interests		0
Net (loss) income attributable to Successor/Predecessor		(192)
Mr. Cooper | Reportable entities
Revenues:
Service related, net	0
Net gain on mortgage loans held for sale	0
Total revenues	0
Expenses:
Salaries, wages and benefits	0
General and administrative	0
Total expenses	0
Other income (expenses):
Interest income	0
Interest expense	(38)
Other income (expenses)	0
Gain (loss) from subsidiaries	(148)
Total other income (expenses), net	(186)
(Loss) income before income tax expense (benefit)	(186)
Less: Income tax (benefit) expense	0
Net (loss) income	(186)
Less: Net (loss) income attributable to non-controlling interests	0
Net (loss) income attributable to Successor/Predecessor	(186)
Mr. Cooper | Reportable entities | Predecessor
Revenues:
Service related, net		0
Net gain on mortgage loans held for sale		0
Total revenues		0
Expenses:
Salaries, wages and benefits		0
General and administrative		0
Total expenses		0
Other income (expenses):
Interest income		0
Interest expense		0
Other income (expenses)		0
Gain (loss) from subsidiaries		160
Total other income (expenses), net		160
(Loss) income before income tax expense (benefit)		160
Less: Income tax (benefit) expense		0
Net (loss) income		160
Less: Net (loss) income attributable to non-controlling interests		0
Net (loss) income attributable to Successor/Predecessor		160
Issuer | Reportable entities
Revenues:
Service related, net	(19)
Net gain on mortgage loans held for sale	166
Total revenues	147
Expenses:
Salaries, wages and benefits	174
General and administrative	165
Total expenses	339
Other income (expenses):
Interest income	118
Interest expense	(134)
Other income (expenses)	4
Gain (loss) from subsidiaries	9
Total other income (expenses), net	(3)
(Loss) income before income tax expense (benefit)	(195)
Less: Income tax (benefit) expense	47
Net (loss) income	(148)
Less: Net (loss) income attributable to non-controlling interests	0
Net (loss) income attributable to Successor/Predecessor	(148)
Issuer | Reportable entities | Predecessor
Revenues:
Service related, net		390
Net gain on mortgage loans held for sale		124
Total revenues		514
Expenses:
Salaries, wages and benefits		152
General and administrative		156
Total expenses		308
Other income (expenses):
Interest income		131
Interest expense		(162)
Other income (expenses)		(1)
Gain (loss) from subsidiaries		32
Total other income (expenses), net		0
(Loss) income before income tax expense (benefit)		206
Less: Income tax (benefit) expense		(46)
Net (loss) income		160
Less: Net (loss) income attributable to non-controlling interests		0
Net (loss) income attributable to Successor/Predecessor		160
Guarantor (Subsidiaries of Issuer) | Reportable entities
Revenues:
Service related, net	6
Net gain on mortgage loans held for sale	0
Total revenues	6
Expenses:
Salaries, wages and benefits	1
General and administrative	1
Total expenses	2
Other income (expenses):
Interest income	0
Interest expense	0
Other income (expenses)	0
Gain (loss) from subsidiaries	0
Total other income (expenses), net	0
(Loss) income before income tax expense (benefit)	4
Less: Income tax (benefit) expense	0
Net (loss) income	4
Less: Net (loss) income attributable to non-controlling interests	0
Net (loss) income attributable to Successor/Predecessor	4
Guarantor (Subsidiaries of Issuer) | Reportable entities | Predecessor
Revenues:
Service related, net		6
Net gain on mortgage loans held for sale		0
Total revenues		6
Expenses:
Salaries, wages and benefits		1
General and administrative		1
Total expenses		2
Other income (expenses):
Interest income		0
Interest expense		0
Other income (expenses)		0
Gain (loss) from subsidiaries		0
Total other income (expenses), net		0
(Loss) income before income tax expense (benefit)		4
Less: Income tax (benefit) expense		0
Net (loss) income		4
Less: Net (loss) income attributable to non-controlling interests		0
Net (loss) income attributable to Successor/Predecessor		4
Non-Guarantor (Subsidiaries of Issuer) | Reportable entities
Revenues:
Service related, net	97
Net gain on mortgage loans held for sale	0
Total revenues	97
Expenses:
Salaries, wages and benefits	40
General and administrative	62
Total expenses	102
Other income (expenses):
Interest income	16
Interest expense	(17)
Other income (expenses)	11
Gain (loss) from subsidiaries	0
Total other income (expenses), net	10
(Loss) income before income tax expense (benefit)	5
Less: Income tax (benefit) expense	0
Net (loss) income	5
Less: Net (loss) income attributable to non-controlling interests	0
Net (loss) income attributable to Successor/Predecessor	$ 5
Non-Guarantor (Subsidiaries of Issuer) | Reportable entities | Predecessor
Revenues:
Service related, net		68
Net gain on mortgage loans held for sale		0
Total revenues		68
Expenses:
Salaries, wages and benefits		27
General and administrative		27
Total expenses		54
Other income (expenses):
Interest income		14
Interest expense		(9)
Other income (expenses)		9
Gain (loss) from subsidiaries		0
Total other income (expenses), net		14
(Loss) income before income tax expense (benefit)		28
Less: Income tax (benefit) expense		0
Net (loss) income		28
Less: Net (loss) income attributable to non-controlling interests		0
Net (loss) income attributable to Successor/Predecessor		$ 28