Stock Based Awards and Other Equity Instruments - Amount of Stock-Based Compensation Expense Related to Stock-Based Awards, Primarily Stock Options and RSUs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 14	$ 14
Income tax benefit from stock-based compensation	(5)	(5)
Total stock-based compensation, net of tax effect	9	9
Selling and Marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	3	2
Technology and Content
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	6	7
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 5	$ 5