Fair Value of Financial Instruments - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015 USD ($) hotel	Jun. 30, 2015 USD ($) hotel	Jun. 30, 2014 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from redemption of ownership		$ 121	$ 0
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial paper, maturity term (generally 30 days or less)		30 days
Mandatorily Redeemable Preferred Equity Ownership Interest | Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of hotels | hotel	3	3
Proceeds from redemption of ownership	$ 121
Amortized cost basis	80	$ 80
Mandatorily Redeemable Preferred Equity Ownership Interest | Debt Securities | Gain and other income, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized gain (loss) of held-to-maturity securities	41
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of our marketable securities	$ 42	$ 42