Other Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expenses	$ 46	$ 45
Other	77	80
Total other current assets	123	125
Accounts Payable, Current [Abstract]
Accounts payable	369	464
Capital expenditures incurred but not yet paid	$ 29	$ 44