Commitments And Contingencies (Narrative) (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Schedule Of Commitments And Contingencies [Line Items]
Loss Contingency Accrual	$ 12
Loss Contingency, Range of Possible Loss, Portion Not Accrued	$ 50
Document Period End Date	Sep. 30, 2017
Purchase obligation over the next twelve months	$ 6,100
Other Receivables	707	$ 586
Realogy [Member]
Schedule Of Commitments And Contingencies [Line Items]
Other Receivables	30
Wyndham [Member]
Schedule Of Commitments And Contingencies [Line Items]
Other Receivables	$ 19