Commitments and Contingencies - Commitments (Detail) € in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) entity	Sep. 30, 2016 EUR (€) entity
Commitments and Contingencies Disclosure [Line Items]
Loan commitment	$ 58
Loan commitment expected to be funded in 2016	10
Loan commitment expected to be funded in 2017	28
Loan commitment expected to be funded thereafter	$ 20
Investment in Other Joint Venture Commitment
Commitments and Contingencies Disclosure [Line Items]
Acquisition interests in joint ventures | entity	2	2
Contingent acquisition period	5 years
Deposits in conjunction with contingent obligation to acquire the interest in joint ventures	$ 20	€ 15
Deposits in conjunction with contingent obligation to acquire the interest in joint ventures, remaining amount	13	€ 11
Information Technology Hardware, Software, Accounting, Finance, and Maintenance Services
Commitments and Contingencies Disclosure [Line Items]
Purchase commitments	477
Purchase commitments expected to be funded in 2016	58
Purchase commitments expected to be funded in 2017	157
Purchase commitments expected to be funded in 2018	115
Purchase commitments expected to be funded thereafter	147
Information Technology Hardware, Software, Accounting, Finance, and Maintenance Services | Starwood Hotels & Resorts Worldwide, Inc.
Commitments and Contingencies Disclosure [Line Items]
Purchase commitments	353
Commitments
Commitments and Contingencies Disclosure [Line Items]
Investment commitments not expected to be funded	41
Full Service and Limited Service | Equity Investment for Non Controlling Interest in Partnership Commitment
Commitments and Contingencies Disclosure [Line Items]
Investment commitments expected to be funded	2
Investment commitments not expected to be funded	7
Full Service and Limited Service | Equity Investment for Non Controlling Interest in Partnership Commitment | Upper Limit
Commitments and Contingencies Disclosure [Line Items]
Investment commitments	$ 9