Indebtedness - Notes Payable Summary (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt Outstanding	$ 567,000,000	$ 595,000,000
Servicing Segment | Notes Payable, Other
Debt Instrument [Line Items]
Debt outstanding, gross	568,000,000	595,000,000
Debt Outstanding	567,000,000	595,000,000
Collateral Pledged	714,000,000	777,000,000
Servicing Segment | Notes Payable, Other | Nationstar mortgage advance receivable trust
Debt Instrument [Line Items]
Capacity Amount	325,000,000
Debt outstanding, gross	229,000,000	209,000,000
Collateral Pledged	$ 290,000,000	284,000,000
Servicing Segment | Notes Payable, Other | Nationstar mortgage advance receivable trust | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.50%
Servicing Segment | Notes Payable, Other | Nationstar mortgage advance receivable trust | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	6.50%
Servicing Segment | Notes Payable, Other | Nationstar agency advance receivable trust
Debt Instrument [Line Items]
Capacity Amount	$ 250,000,000
Debt outstanding, gross	162,000,000	218,000,000
Collateral Pledged	$ 194,000,000	255,000,000
Servicing Segment | Notes Payable, Other | Nationstar agency advance receivable trust | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.50%
Servicing Segment | Notes Payable, Other | Nationstar agency advance receivable trust | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	2.60%
Servicing Segment | Notes Payable, Other | MBS servicer advance facility (2014)
Debt Instrument [Line Items]
Capacity Amount	$ 200,000,000
Debt outstanding, gross	90,000,000	90,000,000
Collateral Pledged	$ 131,000,000	149,000,000
Servicing Segment | Notes Payable, Other | MBS servicer advance facility (2014) | LIBOR
Debt Instrument [Line Items]
Basis spread on rate	2.50%
Servicing Segment | Notes Payable, Other | Nationstar agency advance financing facility
Debt Instrument [Line Items]
Capacity Amount	$ 125,000,000
Debt outstanding, gross	87,000,000	78,000,000
Collateral Pledged	$ 99,000,000	89,000,000
Servicing Segment | Notes Payable, Other | Nationstar agency advance financing facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.50%
Servicing Segment | Notes Payable, Other | Nationstar agency advance financing facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	7.40%
Servicing Segment | Advance facilities
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (1,000,000)	0
Originations Segment | Mortgage loans, net
Debt Instrument [Line Items]
Debt Outstanding	3,204,000,000	1,528,000,000
Collateral Pledged	3,319,000,000	1,628,000,000
Originations Segment | Reverse mortgage interests
Debt Instrument [Line Items]
Debt Outstanding	652,000,000	722,000,000
Collateral Pledged	754,000,000	838,000,000
Originations Segment | MSR
Debt Instrument [Line Items]
Debt Outstanding	190,000,000	100,000,000
Collateral Pledged	1,214,000,000	1,686,000,000
Originations Segment | Notes Payable to Banks
Debt Instrument [Line Items]
Debt outstanding, gross	3,856,000,000	2,250,000,000
Collateral Pledged	4,073,000,000	2,466,000,000
Originations Segment | Notes Payable to Banks | $1,200 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	1,200,000,000
Debt outstanding, gross	715,000,000	560,000,000
Collateral Pledged	$ 762,000,000	622,000,000
Originations Segment | Notes Payable to Banks | $1,200 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.70%
Originations Segment | Notes Payable to Banks | $1,200 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	3.50%
Originations Segment | Notes Payable to Banks | $1,000 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 1,000,000,000
Debt outstanding, gross	629,000,000	137,000,000
Collateral Pledged	$ 646,000,000	140,000,000
Originations Segment | Notes Payable to Banks | $1,000 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.60%
Originations Segment | Notes Payable to Banks | $1,000 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	2.50%
Originations Segment | Notes Payable to Banks | $750 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 750,000,000
Debt outstanding, gross	416,000,000	119,000,000
Collateral Pledged	$ 424,000,000	122,000,000
Originations Segment | Notes Payable to Banks | $750 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.40%
Originations Segment | Notes Payable to Banks | $750 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	2.80%
Originations Segment | Notes Payable to Banks | $800 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 800,000,000
Debt outstanding, gross	531,000,000	464,000,000
Collateral Pledged	$ 576,000,000	514,000,000
Originations Segment | Notes Payable to Banks | $800 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.50%
Originations Segment | Notes Payable to Banks | $800 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	2.90%
Originations Segment | Notes Payable to Banks | $600 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 600,000,000
Debt outstanding, gross	226,000,000	151,000,000
Collateral Pledged	$ 258,000,000	168,000,000
Originations Segment | Notes Payable to Banks | $600 warehouse facility | LIBOR
Debt Instrument [Line Items]
Basis spread on rate	2.30%
Originations Segment | Notes Payable to Banks | $500 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 500,000,000
Debt outstanding, gross	382,000,000	187,000,000
Collateral Pledged	$ 395,000,000	200,000,000
Originations Segment | Notes Payable to Banks | $500 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.50%
Originations Segment | Notes Payable to Banks | $500 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	3.00%
Originations Segment | Notes Payable to Banks | $500 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 500,000,000
Debt outstanding, gross	377,000,000	220,000,000
Collateral Pledged	$ 410,000,000	248,000,000
Originations Segment | Notes Payable to Banks | $500 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	1.50%
Originations Segment | Notes Payable to Banks | $500 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	2.80%
Originations Segment | Notes Payable to Banks | $500 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 500,000,000
Debt outstanding, gross	49,000,000	290,000,000
Collateral Pledged	$ 51,000,000	299,000,000
Originations Segment | Notes Payable to Banks | $500 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	2.00%
Originations Segment | Notes Payable to Banks | $500 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	2.30%
Originations Segment | Notes Payable to Banks | $200 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 200,000,000
Debt outstanding, gross	194,000,000	0
Collateral Pledged	$ 187,000,000	0
Basis spread on rate	1.00%
Originations Segment | Notes Payable to Banks | $200 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 200,000,000
Debt outstanding, gross	107,000,000	0
Collateral Pledged	$ 103,000,000	0
Basis spread on rate	1.50%
Originations Segment | Notes Payable to Banks | $200 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 200,000,000
Debt outstanding, gross	104,000,000	0
Collateral Pledged	$ 103,000,000	0
Basis spread on rate	1.50%
Originations Segment | Notes Payable to Banks | $200 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 200,000,000
Debt outstanding, gross	88,000,000	103,000,000
Collateral Pledged	$ 116,000,000	132,000,000
Basis spread on rate	2.00%
Originations Segment | Notes Payable to Banks | $200 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 200,000,000
Debt outstanding, gross	32,000,000	18,000,000
Collateral Pledged	$ 33,000,000	19,000,000
Basis spread on rate	1.20%
Originations Segment | Notes Payable to Banks | $50 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 50,000,000
Debt outstanding, gross	5,000,000	0
Collateral Pledged	$ 7,000,000	0
Originations Segment | Notes Payable to Banks | $50 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	2.70%
Originations Segment | Notes Payable to Banks | $50 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	7.50%
Originations Segment | Notes Payable to Banks | $40 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 40,000,000
Debt outstanding, gross	1,000,000	1,000,000
Collateral Pledged	$ 2,000,000	2,000,000
Basis spread on rate	3.00%
Originations Segment | Mortgage servicing rights
Debt Instrument [Line Items]
Debt outstanding, gross	$ 190,000,000	100,000,000
Collateral Pledged	1,214,000,000	1,686,000,000
Originations Segment | Mortgage servicing rights | $400 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	400,000,000
Debt outstanding, gross	150,000,000	100,000,000
Collateral Pledged	$ 786,000,000	928,000,000
Originations Segment | Mortgage servicing rights | $400 warehouse facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on rate	3.50%
Originations Segment | Mortgage servicing rights | $400 warehouse facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on rate	6.10%
Originations Segment | Mortgage servicing rights | $400 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 400,000,000
Debt outstanding, gross	25,000,000	0
Collateral Pledged	$ 215,000,000	226,000,000
Originations Segment | Mortgage servicing rights | $400 warehouse facility | LIBOR
Debt Instrument [Line Items]
Basis spread on rate	2.30%
Originations Segment | Mortgage servicing rights | $150 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 150,000,000
Debt outstanding, gross	0	0
Collateral Pledged	$ 121,000,000	430,000,000
Originations Segment | Mortgage servicing rights | $150 warehouse facility | LIBOR
Debt Instrument [Line Items]
Basis spread on rate	2.80%
Originations Segment | Mortgage servicing rights | $50 warehouse facility
Debt Instrument [Line Items]
Capacity Amount	$ 50,000,000
Debt outstanding, gross	15,000,000	0
Collateral Pledged	$ 92,000,000	102,000,000
Originations Segment | Mortgage servicing rights | $50 warehouse facility | LIBOR
Debt Instrument [Line Items]
Basis spread on rate	2.80%
Originations Segment | Warehouse Facilities
Debt Instrument [Line Items]
Debt outstanding, gross	$ 4,046,000,000	2,350,000,000
Unamortized debt issuance costs	(1,000,000)	(1,000,000)
Debt Outstanding	4,045,000,000	2,349,000,000
Collateral Pledged	$ 5,287,000,000	$ 4,152,000,000