Unaudited Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Cumulative effect, period of adoption, adjustment	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative effect, period of adoption, adjustment	Total Mr. Cooper Stockholders’ Equity	Total Mr. Cooper Stockholders’ Equity Cumulative effect, period of adoption, adjustment	Non-controlling Interests
Shares outstanding, beginning balance (in shares) at Dec. 31, 2018			1,000	90,821
Stockholders' equity, beginning balance at Dec. 31, 2018	$ 1,945		$ 0	$ 1	$ 1,093	$ 848		$ 1,942		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				240
Shares issued / (surrendered) under incentive compensation plan	(2)				(2)			(2)
Share-based compensation	9				9			9
Net loss	(274)					(273)		(273)		(1)
Shares outstanding, ending balance (in shares) at Jun. 30, 2019			1,000	91,061
Stockholders' equity, ending balance at Jun. 30, 2019	1,678		$ 0	$ 1	1,100	575		1,676		2
Shares outstanding, beginning balance (in shares) at Mar. 31, 2019			1,000	91,042
Stockholders' equity, beginning balance at Mar. 31, 2019	1,761		$ 0	$ 1	1,095	662		1,758		3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				19
Share-based compensation	5				5			5
Net loss	(88)					(87)		(87)		(1)
Shares outstanding, ending balance (in shares) at Jun. 30, 2019			1,000	91,061
Stockholders' equity, ending balance at Jun. 30, 2019	1,678		$ 0	$ 1	1,100	575		1,676		2
Shares outstanding, beginning balance (in shares) at Dec. 31, 2019			1,000	91,118
Stockholders' equity, beginning balance at Dec. 31, 2019	2,231	$ 7	$ 0	$ 1	1,109	1,122	$ 7	2,232	$ 7	(1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				904
Shares issued / (surrendered) under incentive compensation plan	(5)				(5)			(5)
Share-based compensation	10				10			10
Net loss	(98)					(95)		(95)		(3)
Shares outstanding, ending balance (in shares) at Jun. 30, 2020			1,000	92,022
Stockholders' equity, ending balance at Jun. 30, 2020	$ 2,145		$ 0	$ 1	1,114	1,034		2,149		(4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting standards update	us-gaap:AccountingStandardsUpdate201613Member
Shares outstanding, beginning balance (in shares) at Mar. 31, 2020			1,000	91,970
Stockholders' equity, beginning balance at Mar. 31, 2020	$ 2,066		$ 0	$ 1	1,108	961		2,070		(4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				52
Share-based compensation	6				6			6
Net loss	73					73		73
Shares outstanding, ending balance (in shares) at Jun. 30, 2020			1,000	92,022
Stockholders' equity, ending balance at Jun. 30, 2020	$ 2,145		$ 0	$ 1	$ 1,114	$ 1,034		$ 2,149		$ (4)