Earnings Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net income from continuing operations	$ 500	$ 923	$ 1,466
Less: Undistributed earnings attributable to participating stockholders	0	0	8
Less: Premium on retirement of preferred stock	0	0	28
Net income from continuing operations attributable to Mr. Cooper common stockholders	500	923	1,430
Net loss from discontinued operations	0	0	(12)
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	0	(12)
Net income	500	923	1,454
Less: Undistributed earnings attributable to participating stockholders	0	0	8
Net income attributable to common stockholders	$ 500	$ 923	$ 1,418
Income (Loss) from Continuing Operations, Per Basic Share	$ 7.46	$ 12.84	$ 17.39
Income (Loss) from Continuing Operations, Per Diluted Share	7.30	12.50	16.67
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0	0	(0.15)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	0	0	(0.14)
Basic (in dollars per share)	7.46	12.84	17.24
Diluted (in dollars per share)	$ 7.30	$ 12.50	$ 16.53
Weighted average shares of common stock outstanding (in thousands):
Basic (in shares)	67,070	71,885	82,247
Dilutive effect of stock awards (in shares)	1,479	1,933	3,067
Dilutive effect of participating securities (in shares)	0	0	492
Diluted (in shares)	68,549	73,818	85,806