Quarterly report pursuant to Section 13 or 15(d)

New Accounting Pronouncements (Impact of Adoption on Condensed Consolidated Income Statement) (Details)

v3.10.0.1
New Accounting Pronouncements (Impact of Adoption on Condensed Consolidated Income Statement) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Net revenues          
Net revenues $ 435 $ 331 $ 737 $ 620 $ 1,280
Expenses          
Operating 47 43 87 88 183
Total expenses 396 247 641 480 1,031
Income/(loss) before income taxes 29 82 85 136 243
Provision (benefit) for income taxes 8 34 24 55 13
Net income 21 48 61 81 230
Royalties and franchise fees          
Net revenues          
Net revenues 113 95 194 170 364
Marketing, reservation and loyalty          
Net revenues          
Net revenues 124 96 208 173 371
Expenses          
Cost of revenues 124 93 208 174 373
Other          
Net revenues          
Net revenues $ 31 $ 24 $ 54 $ 49 98
Accounting Standards Update 2014-09          
Expenses          
Provision (benefit) for income taxes         (4)
Previously Reported Balance          
Net revenues          
Net revenues         1,347
Expenses          
Operating         205
Total expenses         1,086
Income/(loss) before income taxes         255
Provision (benefit) for income taxes         12
Net income         243
Previously Reported Balance | Royalties and franchise fees          
Net revenues          
Net revenues         375
Previously Reported Balance | Marketing, reservation and loyalty          
Net revenues          
Net revenues         407
Expenses          
Cost of revenues         406
Previously Reported Balance | Other          
Net revenues          
Net revenues         118
New Revenue Standard Adjustment          
Expenses          
Income tax benefit from impact of U.S. Tax Cuts and Jobs Act         (3)
New Revenue Standard Adjustment | Accounting Standards Update 2014-09          
Net revenues          
Net revenues         (67)
Expenses          
Operating         (22)
Total expenses         (55)
Income/(loss) before income taxes         (12)
Provision (benefit) for income taxes         1
Net income         (13)
New Revenue Standard Adjustment | Accounting Standards Update 2014-09 | Royalties and franchise fees          
Net revenues          
Net revenues         (11)
New Revenue Standard Adjustment | Accounting Standards Update 2014-09 | Marketing, reservation and loyalty          
Net revenues          
Net revenues         (36)
Expenses          
Cost of revenues         (33)
New Revenue Standard Adjustment | Accounting Standards Update 2014-09 | Other          
Net revenues          
Net revenues         $ (20)