Earnings Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Net income from continuing operations	$ 923	$ 1,466	$ 309
Less: Net income attributable to non-controlling interests	0	0	2
Less: Undistributed earnings attributable to participating stockholders	0	8	3
Less: Premium on retirement of preferred stock	0	28	0
Net income from continuing operations attributable to Mr. Cooper common stockholders	923	1,430	304
Net loss from discontinued operations	0	(12)	(2)
Less: Undistributed earnings from discontinued operations attributable to participating stockholders	0	0	0
Net loss from discontinued operations attributable to Mr. Cooper common stockholders	0	(12)	(2)
Net income	923	1,454	307
Less: Net income attributable to non-controlling interests	0	0	2
Net income attributable to Mr. Cooper	923	1,454	305
Less: Undistributed earnings attributable to participating stockholders	0	8	3
Net income attributable to common stockholders	$ 923	$ 1,418	$ 302
Income (Loss) from Continuing Operations, Per Basic Share	$ 12.84	$ 17.39	$ 3.33
Income (Loss) from Continuing Operations, Per Diluted Share	12.50	16.67	3.22
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0	(0.15)	(0.02)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	0	(0.14)	(0.02)
Basic (in dollars per share)	12.84	17.24	3.31
Diluted (in dollars per share)	$ 12.50	$ 16.53	$ 3.20
Weighted average shares of common stock outstanding (in thousands):
Basic (in shares)	71,885	82,247	91,312
Dilutive effect of stock awards (in shares)	1,933	3,067	2,343
Dilutive effect of participating securities (in shares)	0	492	839
Diluted (in shares)	73,818	85,806	94,494