Unaudited Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Service related, net	$ 288	$ 218	$ 860	$ 151
Net gain on mortgage loans held for sale	572	645	1,833	1,594
Total revenues	860	863	2,693	1,745
Expenses:
Salaries, wages and benefits	251	265	805	737
General and administrative	151	190	476	540
Total expenses	402	455	1,281	1,277
Interest income	66	17	163	114
Interest expense	(118)	(128)	(363)	(394)
Other income (expense), net	8	(51)	494	(50)
Total other (expense) income, net	(44)	(162)	294	(330)
Income (loss) from continuing operations before income tax expense (benefit)	414	246	1,706	138
Less: Income tax expense	104	59	410	33
Net income from continuing operations	310	187	1,296	105
Net (loss) income from discontinued operations	(11)	27	3	11
Net income	299	214	1,299	116
Less: Net earnings attributable to non-controlling interests	0	5	0	2
Net income attributable to Mr. Cooper	299	209	1,299	114
Less: Undistributed earnings attributable to participating stockholders	1	2	9	1
Less: Premium on retirement of preferred stock	28	0	28	0
Net income attributable to common stockholders	$ 270	$ 207	$ 1,262	$ 113
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 3.56	$ 1.98	$ 14.85	$ 1.12
Income (Loss) from Continuing Operations, Per Diluted Share	3.42	1.91	14.20	1.09
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	(0.14)	0.28	0.04	0.11
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	(0.13)	0.27	0.03	0.11
Basic (in dollars per share)	3.42	2.26	14.89	1.23
Diluted (in dollars per share)	$ 3.29	$ 2.18	$ 14.23	$ 1.20