Segment Information - Financial Information (Details) - USD ($) $ in Millions	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Service related, net	$ 418	$ 901	$ 423	$ 909
Net gain on mortgage loans held for sale	176	295	2,310	1,098
Total revenues	594	1,196	2,733	2,007
Total expenses	707	945	1,831	1,851
Other income (expenses), net:
Interest income	256	333	334	605
Interest expense	(293)	(388)	(702)	(779)
Other income (expenses), net	13	6	(135)	15
Total other income (expenses), net	(24)	(49)	(503)	(159)
Income (loss) before income tax expense (benefit)	(137)	202	399	(3)
Depreciation and amortization for property and equipment and intangible assets	39	33	74	91
Total assets	16,973	17,026	24,165	18,305
Eliminations/ Reclassifications
Revenues:
Service related, net		(25)
Net gain on mortgage loans held for sale		25
Total revenues		0
Total expenses		0
Other income (expenses), net:
Interest income		0
Interest expense		0
Other income (expenses), net		0
Total other income (expenses), net		0
Income (loss) before income tax expense (benefit)		0
Depreciation and amortization for property and equipment and intangible assets		0
Total assets		(3,591)
Operating Segments
Revenues:
Service related, net		900
Net gain on mortgage loans held for sale		295
Total revenues		1,195
Total expenses		842
Other income (expenses), net:
Interest income		326
Interest expense		(305)
Other income (expenses), net		8
Total other income (expenses), net		29
Income (loss) before income tax expense (benefit)		382
Depreciation and amortization for property and equipment and intangible assets		29
Total assets		16,113
Operating Segments | Servicing
Revenues:
Service related, net	217	740	(115)	408
Net gain on mortgage loans held for sale	19	0	222	124
Total revenues	236	740	107	532
Total expenses	303	474	539	690
Other income (expenses), net:
Interest income	222	288	237	500
Interest expense	(173)	(268)	(442)	(469)
Other income (expenses), net	6	(1)	0	4
Total other income (expenses), net	55	19	(205)	35
Income (loss) before income tax expense (benefit)	(12)	285	(637)	(123)
Depreciation and amortization for property and equipment and intangible assets	9	15	20	19
Total assets	13,460	14,578	16,173	11,743
Operating Segments | Originations
Revenues:
Service related, net	24	36	105	80
Net gain on mortgage loans held for sale	157	270	2,088	963
Total revenues	181	306	2,193	1,043
Total expenses	155	245	746	568
Other income (expenses), net:
Interest income	27	38	95	98
Interest expense	(26)	(37)	(78)	(98)
Other income (expenses), net	5	0	0	4
Total other income (expenses), net	6	1	17	4
Income (loss) before income tax expense (benefit)	32	62	1,464	479
Depreciation and amortization for property and equipment and intangible assets	5	7	18	18
Total assets	1,498	4,701	5,447	4,313
Operating Segments | Xome
Revenues:
Service related, net	177	149	433	422
Net gain on mortgage loans held for sale	0	0	0	0
Total revenues	177	149	433	422
Total expenses	178	123	389	398
Other income (expenses), net:
Interest income	0	0	0	0
Interest expense	(1)	0	0	0
Other income (expenses), net	1	9	4	14
Total other income (expenses), net	0	9	4	14
Income (loss) before income tax expense (benefit)	(1)	35	48	38
Depreciation and amortization for property and equipment and intangible assets	5	7	15	14
Total assets	167	425	128	139
Corporate/ Other
Revenues:
Service related, net	0	1	0	(1)
Net gain on mortgage loans held for sale	0	0	0	11
Total revenues	0	1	0	10
Total expenses	71	103	157	195
Other income (expenses), net:
Interest income	7	7	2	7
Interest expense	(93)	(83)	(182)	(212)
Other income (expenses), net	1	(2)	(139)	(7)
Total other income (expenses), net	(85)	(78)	(319)	(212)
Income (loss) before income tax expense (benefit)	(156)	(180)	(476)	(397)
Depreciation and amortization for property and equipment and intangible assets	20	4	21	40
Total assets	$ 1,848	$ 913	$ 2,417	$ 2,110