Unaudited Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Total Mr. Cooper Stockholders’ Equity	Non-controlling Interests	Treasury Share Amount
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ equity	$ 3,367	$ 1	$ 1,116	$ 2,879	$ 3,366	$ 1	$ (630)
Shares outstanding, beginning balance (in shares) at Dec. 31, 2021		73,777
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)		898
Shares issued / (surrendered) under incentive compensation plan	(22)		(41)		(22)		19
Share-based compensation	24		24		24
Repurchase of common stock (in shares)		(4,118)
Dividends paid to noncontrolling interests	(1)					(1)
Repurchase of common stock	(185)				(185)		(185)
Net income	922			922	922	0
Shares outstanding, ending balance (in shares) at Sep. 30, 2022		70,557
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ equity	4,037	$ 1	1,094	3,688	4,036	1	(747)
Shares outstanding, beginning balance (in shares) at Jun. 30, 2022		71,651
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)		42
Shares issued / (surrendered) under incentive compensation plan	(1)		(2)		(1)		1
Share-based compensation	7		7		7
Repurchase of common stock (in shares)		(1,136)
Dividends paid to noncontrolling interests	(1)					(1)
Repurchase of common stock	(50)				(50)		(50)
Net income	113			113	113	0
Shares outstanding, ending balance (in shares) at Sep. 30, 2022		70,557
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ equity	4,105	$ 1	1,099	3,801	4,105	0	(796)
Total stockholders’ equity	4,057	$ 1	1,104	3,802	4,057	0	(850)
Shares outstanding, beginning balance (in shares) at Dec. 31, 2022		69,266
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)		902
Shares issued / (surrendered) under incentive compensation plan	(24)		(44)		(24)		20
Share-based compensation	21		21		21
Repurchase of common stock (in shares)		(4,334)
Repurchase of common stock	(204)				(204)		(204)
Net income	454			454	454	0
Shares outstanding, ending balance (in shares) at Sep. 30, 2023		65,834
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ equity	4,079	$ 1	1,074	3,981	4,079	0	(977)
Shares outstanding, beginning balance (in shares) at Jun. 30, 2023		66,848
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued / (surrendered) under incentive compensation plan (in shares)		25
Shares issued / (surrendered) under incentive compensation plan	0		(1)		0		1
Share-based compensation	8		8		8
Repurchase of common stock (in shares)		(1,039)
Repurchase of common stock	(58)				(58)		(58)
Net income	275			275	275	0
Shares outstanding, ending balance (in shares) at Sep. 30, 2023		65,834
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ equity	$ 4,304	$ 1	$ 1,081	$ 4,256	$ 4,304	$ 0	$ (1,034)