Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities:
Net income	$ 68	$ 62
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	10	6
Stock-based compensation	14	14
Amortization of intangible assets	2	1
Amortization of discounts and premiums on marketable securities, net	1	1
Deferred tax expense (benefit)	1	(3)
Excess tax benefits from stock-based compensation	(11)	(1)
Other, net	1	2
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	(38)	(47)
Prepaid expenses and other assets		(2)
Accounts payable, accrued expenses and other liabilities	(5)	(17)
Deferred merchant payables	34	5
Income taxes, net	18	19
Deferred revenue	14	4
Net cash provided by operating activities	109	44
Investing activities:
Acquisitions, net of cash acquired		(1)
Capital expenditures, including internal-use software and website development	(20)	(9)
Purchases of marketable securities	(203)	(214)
Sales of marketable securities	52	14
Maturities of marketable securities	44	31
Net cash used in investing activities	(127)	(179)
Financing activities:
Proceeds from credit facilities	5	4
Payments to credit facilities	(3)	(15)
Principal payments on long-term debt	(10)	(10)
Proceeds from exercise of stock options	2	6
Payment of minimum withholding taxes on net share settlements of equity awards	(18)	(5)
Excess tax benefits from stock-based compensation	11	1
Payments on construction in-process related to build to suit lease obligations	(1)
Net cash used in financing activities	(14)	(19)
Effect of exchange rate changes on cash and cash equivalents		(2)
Net decrease in cash and cash equivalents	(32)	(156)
Cash and cash equivalents at beginning of period	351	368
Cash and cash equivalents at end of period	319	212
Supplemental disclosure of non-cash investing and financing activities:
Capitalization of construction in-process related to build to suit lease obligation	$ 14