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
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income from continuing operations	$ 658	$ 559
Less: Undistributed earnings from continuing operations attributable to participating stockholders	0	5
Net income from continuing operations attributable to Mr. Cooper common stockholders	658	554
Net income from discontinued operations	0	2
Less: Undistributed earnings from discontinued operations attributable to participating stockholders	0	0
Net income from discontinued operations attributable to Mr. Cooper common stockholders	0	2
Net income	658	561
Less: Undistributed earnings attributable to participating stockholders	0	5
Net income attributable to common stockholders	$ 658	$ 556
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 8.91	$ 6.20
Income (Loss) from Continuing Operations, Per Diluted Share	8.59	5.90
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0	0.02
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	0	0.02
Basic (in dollars per share)	8.91	6.22
Diluted (in dollars per share)	$ 8.59	$ 5.92
Weighted average shares of common stock outstanding (in thousands):
Basic (in shares)	73,864	89,458
Dilutive effect of stock awards (in shares)	2,704	3,590
Dilutive effect of participating securities (in shares)	0	839
Diluted (in shares)	76,568	93,887