Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Allowance for doubtful accounts	$ 2	$ 2
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	2,500,000,000	2,500,000,000
Common stock, shares issued (shares)	122,920,000	129,359,000
Common stock, shares outstanding (shares)	122,920,000	129,359,000
Class B Convertible Common Stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (shares)	300,000,000	300,000,000
Common stock, shares outstanding (shares)	300,000,000	300,000,000