Variable Interest Entities (Details) - USD ($) $ in Millions			1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
		Feb. 15, 2017	Oct. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents				$ 494			$ 996	$ 494	$ 996		$ 906	$ 906
Restricted cash				52				52			57
Mortgage loans held for sale				590				590			683
Accounts receivable, net				94				94			66
Servicing advances, net				413				413			628
Property and equipment, net				24				24			36
Other assets				54				54			109
Total assets	[1]			2,301				2,301			3,175
LIABILITIES
Accounts payable and accrued expenses				218				218			193
Debt, net				653				653			1,262
Other liabilities				86				86			157
Total liabilities	[1]			1,663				1,663			2,052
Variable Interest Entities Additional Information [Abstract]
Proceeds from PHH Home Loans asset sales				28				28	0
Gain on PHH Home Loans asset sales				28				28	0
Exit and disposal costs				8			$ 0	$ 49	$ 0
Notice period of purchase requirement								2 years
Variable Interest Entity
ASSETS
Cash and cash equivalents				60				$ 60			67
Restricted cash				18				18			24
Mortgage loans held for sale				239				239			350
Accounts receivable, net				17				17			9
Servicing advances, net				80				80			150
Property and equipment, net				0				0			1
Other assets				7				7			12
Total assets				421				421			613
LIABILITIES
Accounts payable and accrued expenses				14				14			11
Debt, net				258				258			399
Other liabilities				6				6			5
Total liabilities				278				278			415
PHH Home Loans | Variable Interest Entity
ASSETS
Cash and cash equivalents				60				60			67
Restricted cash				4				4			5
Mortgage loans held for sale				239				239			350
Accounts receivable, net				17				17			9
Servicing advances, net				0				0			0
Property and equipment, net				0				0			1
Other assets				7				7			11
Total assets				327				327			443
Assets held as collateral				218				218			320
LIABILITIES
Accounts payable and accrued expenses				14				14			11
Debt, net				206				206			300
Other liabilities				6				6			5
Total liabilities				226				226			316
Servicing Advance Receivables Trust | Variable Interest Entity
ASSETS
Cash and cash equivalents				0				0			0
Restricted cash				14				14			19
Mortgage loans held for sale				0				0			0
Accounts receivable, net				0				0			0
Servicing advances, net				80				80			150
Property and equipment, net				0				0			0
Other assets				0				0			1
Total assets				94				94			170
Assets held as collateral				94				94			169
LIABILITIES
Accounts payable and accrued expenses				0				0			0
Debt, net				52				52			99
Other liabilities				0				0			0
Total liabilities				52				$ 52			$ 99
Mortgage Production Volume | Realogy and Affiliates | Credit Concentration Risk
Variable Interest Entities Additional Information [Abstract]
Concentration risk, percentage								29.00%
PHH Home Loans Joint Venture
Variable Interest Entities Additional Information [Abstract]
Purchase by Parent of additional equity interest, percent		49.90%
Forecast
Variable Interest Entities Additional Information [Abstract]
Proceeds from sale of assets										$ 96
Reorganization
Variable Interest Entities Additional Information [Abstract]
Exit and disposal costs				5	$ 8	$ 17		$ 30
Reorganization | PHH Home Loans Joint Venture
Variable Interest Entities Additional Information [Abstract]
Exit and disposal costs				$ 4				$ 9
Subsequent Event
Variable Interest Entities Additional Information [Abstract]
Proceeds from PHH Home Loans asset sales			$ 14

[1] The Condensed Consolidated Balance Sheets include assets and liabilities of variable interest entities which can be used only to settle the obligations and liabilities of the variable interest entities which creditors or beneficial interest holders do not have recourse to PHH Corporation and subsidiaries. These assets and liabilities are as follows: September 30, 2017 December 31, 2016ASSETS Cash and cash equivalents$60 $67Restricted cash18 24Mortgage loans held for sale239 350Accounts receivable, net17 9Servicing advances, net80 150Property and equipment, net— 1Other assets7 12Total assets$421 $613 LIABILITIES Accounts payable and accrued expenses$14 $11Debt258 399Other liabilities6 5Total liabilities$278 $415