Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net income	$ 40	$ 64
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment, including amortization of internal-use software and website development	38	33
Amortization of intangible assets	16	15
Stock-based compensation expense	47	43
Deferred tax (benefit) expense	(2)	(5)
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable, prepaid expenses and other assets	(51)	(51)
Accounts payable, accrued expenses and other liabilities	29	43
Deferred merchant payables	208	179
Income tax receivables/payables, net	5	8
Deferred revenue	25	34
Net cash provided by operating activities	355	363
Investing activities:
Capital expenditures, including internal-use software and website development	(35)	(36)
Purchases of marketable securities	(7)	(98)
Sales of marketable securities	103	40
Maturities of marketable securities	17	17
Other investing activities, net		1
Net cash provided by (used in) investing activities	78	(76)
Financing activities:
Repurchase of common stock	(250)	(12)
Proceeds from exercise of stock options	3	3
Payment of withholding taxes on net share settlements of equity awards	(14)	(11)
Net cash used in financing activities	(167)	(129)
Effect of exchange rate changes on cash and cash equivalents	9	(6)
Net increase in cash and cash equivalents	275	152
Cash and cash equivalents at beginning of period	612	614
Cash and cash equivalents at end of period	887	766
Supplemental disclosure of non-cash investing and financing activities:
Stock-based compensation capitalized with internal-use software and website development costs	6	6
2015 Credit Facility
Financing activities:
Proceeds from credit facility, net of financing costs	373
Payments to credit facility	(206)	$ (109)
2016 Credit Facility
Financing activities:
Payments to credit facility	$ (73)