Derivative and Financial Instruments - Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Credit Risk [Line items]
Collateral was posted for derivative instruments in a liability position	$ 2	$ 0
Aggregate fair value of all derivative instruments in a liability position	$ 158	$ 150
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Terms of financial instruments and trade receivables	30 days	30 days
In event of lowered credit rating [Member]
Schedule of Credit Risk [Line items]
Additional collateral, either in the form of cash or letters of credit	$ 156
In event of downgrade below investment grade [Member]
Schedule of Credit Risk [Line items]
Additional collateral, either in the form of cash or letters of credit	$ 0