Unaudited Condensed 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 Mr. Cooper Stockholders’ Equity	Non-controlling Interests
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)			1,183
Shares issued / (surrendered) under incentive compensation plan	(19)			(19)			(19)
Share-based compensation	6			6			6
Repurchase of common stock (in shares)			(4,505)
Repurchase of common stock	(148)					(148)	(148)
Net income	561				561		561	0
Shares outstanding, ending balance (in shares) at Mar. 31, 2021		1,000	86,135
Stockholders' equity, ending balance at Mar. 31, 2021	2,904	$ 0	$ 1	1,113	1,995	(206)	2,903	1
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]
Repurchase of common stock (in shares)			14,773
Shares outstanding, ending balance (in shares) at Dec. 31, 2021		0	73,777
Stockholders' equity, ending balance at Dec. 31, 2021	3,367	$ 0	$ 1	1,116	2,879	(630)	3,366	1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)			850
Shares issued / (surrendered) under incentive compensation plan	(21)			(39)		18	(21)
Share-based compensation	8			8			8
Repurchase of common stock (in shares)			(721)
Repurchase of common stock	(35)					(35)	(35)
Net income	658				658		658	0
Shares outstanding, ending balance (in shares) at Mar. 31, 2022		0	73,906
Stockholders' equity, ending balance at Mar. 31, 2022	$ 3,977	$ 0	$ 1	$ 1,085	$ 3,537	$ (647)	$ 3,976	$ 1