Earnings Per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income from continuing operations	$ 113	$ 310	$ 922	$ 1,296
Less: Undistributed earnings from continuing operations attributable to participating stockholders	0	1	0	9
Net income from continuing operations attributable to Mr. Cooper common stockholders	113	281	922	1,259
Net (loss) income from discontinued operations	0	(11)	0	3
Less: Undistributed earnings from discontinued operations attributable to participating stockholders	0	0	0	0
Net (loss) income from discontinued operations attributable to Mr. Cooper common stockholders	0	(11)	0	3
Net income	113	299	922	1,299
Less: Undistributed earnings attributable to participating stockholders	0	1	0	9
Net income attributable to common stockholders	$ 113	$ 270	$ 922	$ 1,262
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 1.59	$ 3.56	$ 12.71	$ 14.85
Income (Loss) from Continuing Operations, Per Diluted Share	1.55	3.42	12.37	14.20
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0	(0.14)	0	0.04
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	0	(0.13)	0	0.03
Basic (in dollars per share)	1.59	3.42	12.71	14.89
Diluted (in dollars per share)	$ 1.55	$ 3.29	$ 12.37	$ 14.23
Weighted average shares of common stock outstanding (in thousands):
Basic	71,175	78,944	72,569	84,809
Dilutive effect of stock awards	1,703	2,826	1,988	3,176
Dilutive effect of participating securities	0	301	0	658
Diluted	72,878	82,071	74,557	88,643