Unaudited Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Share Amount	Total Nationstar Stockholders’ Equity and Mr. Cooper Stockholders’ Equity, respectively	Non-controlling Interests
Beginning of Period, shares (Predecessor) at Dec. 31, 2017			97,728
Beginning of Period (Predecessor) at Dec. 31, 2017	$ 1,722		$ 1	$ 1,131	$ 731	$ (148)	$ 1,715	$ 7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan, shares | Predecessor			465
Shares issued / (surrendered) under incentive compensation plan | Predecessor	(4)			(4)			(4)
Share-based compensation | Predecessor	4			4			4
Net income (loss) | Predecessor	160				160		160	0
Ending of Period (Predecessor) at Mar. 31, 2018	1,882		$ 1	1,131	891	(148)	1,875	7
Ending of Period, shares (Predecessor) at Mar. 31, 2018			98,193
Beginning of Period, shares at Dec. 31, 2018		1,000	90,821
Beginning of Period at Dec. 31, 2018	1,945	$ 0	$ 1	1,093	848	0	1,942	3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan, shares			221
Shares issued / (surrendered) under incentive compensation plan	(2)			(2)			(2)
Share-based compensation	4			4			4
Net income (loss)	(186)				(186)		(186)	0
Ending of Period at Mar. 31, 2019	$ 1,761	$ 0	$ 1	$ 1,095	$ 662	$ 0	$ 1,758	$ 3
Ending of Period, shares at Mar. 31, 2019		1,000	91,042