Fair Value of Financial Instruments - Additional Information (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) hotel	Dec. 31, 2015 USD ($)
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
Proceeds from redemption of ownership	$ 121
Amortized cost basis	80
Gains and Other Income, Net | Mandatorily Redeemable Preferred Equity Ownership Interest | Debt Securities
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		$ 37