Business Segment Reporting - Financial Information (Details) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended							5 Months Ended	7 Months Ended	12 Months Ended
	Jul. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment												4
Revenues:
Service related, net	$ 120	$ 259	$ 430	$ 258	$ 137	$ 84	$ 159	$ 317	$ 464	$ 418	$ 901	$ 909	$ 1,043
Net gain on mortgage loans held for sale	44	83	310	360	262	166	93	127	124	176	295	1,098	607
Total revenues	164	342	740	618	399	250	252	444	588	594	1,196	2,007	1,650
Total expenses	242	275	438	478	492	443	432	339	364	707	945	1,851	1,475
Other income (expenses), net:
Interest income										256	333	605	597
Interest expense										(293)	(388)	(779)	(731)
Other (expenses) income, net										13	6	15	3
Total other income (expenses), net	(5)	(26)	(62)	(33)	(24)	(40)	2	(26)	(18)	(24)	(49)	(159)	(131)
(Loss) income before income tax expense	(83)	$ 41	240	$ 107	$ (117)	$ (233)	(178)	$ 79	$ 206	(137)	202	(3)	44
Depreciation and amortization for property and equipment and intangible assets										39	33	91	59
Total assets	17,026		18,305				16,973			16,973	17,026	18,305	18,036
Eliminations
Revenues:
Service related, net										0	(25)	(3)	(79)
Net gain on mortgage loans held for sale										0	25	0	79
Total revenues										0	0	(3)	0
Total expenses										0	0	(3)	0
Other income (expenses), net:
Interest income										0	0	0	0
Interest expense										0	0	0	0
Other (expenses) income, net										0	0	0	0
Total other income (expenses), net										0	0	0	0
(Loss) income before income tax expense										0	0	0	0
Depreciation and amortization for property and equipment and intangible assets										0	0	0	0
Total assets	(3,591)		(4,826)				(3,772)			(3,772)	(3,591)	(4,826)	(3,117)
Total Operating Segments
Revenues:
Service related, net										418	900	907	1,041
Net gain on mortgage loans held for sale										176	295	1,087	607
Total revenues										594	1,195	1,994	1,648
Total expenses										636	842	1,653	1,377
Other income (expenses), net:
Interest income										249	326	598	582
Interest expense										(200)	(305)	(567)	(577)
Other (expenses) income, net										12	8	22	6
Total other income (expenses), net										61	29	53	11
(Loss) income before income tax expense										19	382	394	282
Depreciation and amortization for property and equipment and intangible assets										19	29	51	47
Total assets	16,113		16,001				15,072			15,072	16,113	16,001	17,217
Total Operating Segments | Servicing
Revenues:
Service related, net										217	740	408	766
Net gain on mortgage loans held for sale										19	0	124	0
Total revenues										236	740	532	766
Total expenses										303	474	690	691
Other income (expenses), net:
Interest income										222	288	500	527
Interest expense										(173)	(268)	(469)	(523)
Other (expenses) income, net										6	(1)	4	(3)
Total other income (expenses), net										55	19	35	1
(Loss) income before income tax expense										(12)	285	(123)	76
Depreciation and amortization for property and equipment and intangible assets										9	15	19	23
Total assets	14,578		11,044				13,485			13,485	14,578	11,044	15,006
Total Operating Segments | Originations
Revenues:
Service related, net										24	36	80	63
Net gain on mortgage loans held for sale										157	270	963	528
Total revenues										181	306	1,043	591
Total expenses										155	245	568	439
Other income (expenses), net:
Interest income										27	38	98	55
Interest expense										(26)	(37)	(98)	(54)
Other (expenses) income, net										5	0	4	0
Total other income (expenses), net										6	1	4	1
(Loss) income before income tax expense										32	62	479	153
Depreciation and amortization for property and equipment and intangible assets										5	7	18	10
Total assets	4,701		9,257				4,866			4,866	4,701	9,257	4,935
Total Operating Segments | Xome
Revenues:
Service related, net										177	149	422	291
Net gain on mortgage loans held for sale										0	0	0	0
Total revenues										177	149	422	291
Total expenses										178	123	398	247
Other income (expenses), net:
Interest income										0	0	0	0
Interest expense										(1)	0	0	0
Other (expenses) income, net										1	9	14	9
Total other income (expenses), net										0	9	14	9
(Loss) income before income tax expense										(1)	35	38	53
Depreciation and amortization for property and equipment and intangible assets										5	7	14	14
Total assets	425		526				493			493	425	526	393
Corporate/ Other
Revenues:
Service related, net										0	1	2	2
Net gain on mortgage loans held for sale										0	0	11	0
Total revenues										0	1	13	2
Total expenses										71	103	198	98
Other income (expenses), net:
Interest income										7	7	7	15
Interest expense										(93)	(83)	(212)	(154)
Other (expenses) income, net										1	(2)	(7)	(3)
Total other income (expenses), net										(85)	(78)	(212)	(142)
(Loss) income before income tax expense										(156)	(180)	(397)	(238)
Depreciation and amortization for property and equipment and intangible assets										20	4	40	12
Total assets	$ 913		$ 2,304				$ 1,901			$ 1,901	$ 913	$ 2,304	$ 819