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)			1,197
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	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 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)			14,800
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
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	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
Shares outstanding, beginning balance (in shares) at Dec. 31, 2021		0	73,777
Stockholders' equity, beginning 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)			856
Shares issued / (surrendered) under incentive compensation plan	(21)			(39)		18	(21)
Share-based compensation	17			17			17
Repurchase of common stock (in shares)			(2,982)
Repurchase of common stock	(135)					(135)	(135)
Net income	809				809		809	0
Shares outstanding, ending balance (in shares) at Jun. 30, 2022		0	71,651
Stockholders' equity, ending balance at Jun. 30, 2022	4,037	$ 0	$ 1	1,094	3,688	(747)	4,036	1
Shares outstanding, beginning balance (in shares) at Mar. 31, 2022		0	73,906
Stockholders' equity, beginning balance at Mar. 31, 2022	3,977	$ 0	$ 1	1,085	3,537	(647)	3,976	1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)			6
Shares issued / (surrendered) under incentive compensation plan	0			0		0	0
Share-based compensation	9			9			9
Repurchase of common stock (in shares)			(2,261)
Repurchase of common stock	(100)					(100)	(100)
Net income	151				151		151	0
Shares outstanding, ending balance (in shares) at Jun. 30, 2022		0	71,651
Stockholders' equity, ending balance at Jun. 30, 2022	$ 4,037	$ 0	$ 1	$ 1,094	$ 3,688	$ (747)	$ 4,036	$ 1