Other Financial Information (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expenses	$ 70	$ 46
Other	78	77
Total other current assets	148	123
Accounts Payable, Current [Abstract]
Accounts payable	350	369
Capital expenditures incurred and included in accounts payable	$ 29	$ 29