Unaudited Condensed 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	Treasury Share Amount	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, 2019			1,000	91,118
Stockholders' equity, beginning balance at Dec. 31, 2019	$ 2,231	$ 7	$ 0	$ 1	$ 1,109	$ 1,122	$ 7	$ 0	$ 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 income (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		0	2,149		(4)
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		0	2,070		(4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				52
Shares issued / (surrendered) under incentive compensation plan	0				0				0
Share-based compensation	6				6				6
Net income (loss)	73					73			73		0
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		0	2,149		(4)
Shares outstanding, beginning balance (in shares) at Dec. 31, 2020			1,000	89,457
Stockholders' equity, beginning balance at Dec. 31, 2020	2,504		$ 0	$ 1	1,126	1,434		(58)	2,503		1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				1,197
Shares issued / (surrendered) under incentive compensation plan	(20)				(20)				(20)
Share-based compensation	14				14				14
Repurchase of common stock (in shares)				(4,505)
Repurchase of common stock	(148)							(148)	(148)
Net income (loss)	1,000					1,000			1,000		0
Shares outstanding, ending balance (in shares) at Jun. 30, 2021			1,000	86,149
Stockholders' equity, ending balance at Jun. 30, 2021	3,350		$ 0	$ 1	1,120	2,434		(206)	3,349		1
Shares outstanding, beginning balance (in shares) at Mar. 31, 2021			1,000	86,135
Stockholders' equity, beginning balance at Mar. 31, 2021	2,904		$ 0	$ 1	1,113	1,995		(206)	2,903		1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)				14
Shares issued / (surrendered) under incentive compensation plan	(1)				(1)				(1)
Share-based compensation	8				8				8
Net income (loss)	439					439			439		0
Shares outstanding, ending balance (in shares) at Jun. 30, 2021			1,000	86,149
Stockholders' equity, ending balance at Jun. 30, 2021	$ 3,350		$ 0	$ 1	$ 1,120	$ 2,434		$ (206)	$ 3,349		$ 1