Financial and Derivative Instruments (Details) - Commodity [Member] - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheet: Fair Value of Derivatives not Designated as Hedging Instruments
Total Assets at Fair Value	$ 73	$ 32
Total Liabilities at Fair Value	8	109
Accounts and notes receivable, net [Member]
Consolidated Balance Sheet: Fair Value of Derivatives not Designated as Hedging Instruments
Total Assets at Fair Value	70	30
Long term receivables, net [Member]
Consolidated Balance Sheet: Fair Value of Derivatives not Designated as Hedging Instruments
Total Assets at Fair Value	3	2
Accounts payable [Member]
Consolidated Balance Sheet: Fair Value of Derivatives not Designated as Hedging Instruments
Total Liabilities at Fair Value	6	99
Deferred credits and other noncurrent obligations [Member]
Consolidated Balance Sheet: Fair Value of Derivatives not Designated as Hedging Instruments
Total Liabilities at Fair Value	$ 2	$ 10