Commitments And Contingencies (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2017	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Schedule Of Commitments And Contingencies [Line Items]
Loss Contingency Accrual		$ 12	$ 26
Loss Contingency, Loss in Period	$ 13
Insurance Settlements Receivable		27
Loss Contingency, Range of Possible Loss, Portion Not Accrued		$ 50
Document Period End Date		Jun. 30, 2017
Purchase obligation over the next twelve months		$ 1,700
Other Receivables		235		$ 251
Realogy [Member]
Schedule Of Commitments And Contingencies [Line Items]
Other Receivables		41
Wyndham [Member]
Schedule Of Commitments And Contingencies [Line Items]
Other Receivables		$ 25