Cost of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Cost of Revenue [Abstract]
Corporate Office Costs	$ 47	$ 89	$ 124	$ 166
Share-based Compensation	$ 15	$ 12	$ 30	$ 22