Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Provision for accrued expenses	$ 100	$ 87
Deferred loyalty rewards	183	166
Net operating loss and tax credit carryforwards	100	123
Stock-based compensation	86	67
Property and equipment	102	55
Operating lease liabilities	136	0
Other	72	68
Total deferred tax assets	779	566
Less valuation allowance	(77)	(80)
Net deferred tax assets	702	486
Deferred tax liabilities:
Goodwill and intangible assets	(485)	(486)
Operating lease ROU assets	(128)	0
Total deferred tax liabilities	(613)	(486)
Net deferred tax liability	$ 89	$ 0