Advertising and Promotion Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Marketing and Advertising Expense [Abstract]
Advertising and certain promotion expenses	$ 7	$ 7	$ 16	$ 15