Fair Value Measurements (Details 3-Reported)	May 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure		$ 755,000,000	$ 7,000,000
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Other noncurrent financial assets		127,000,000	105,000,000
Total financial assets		882,000,000	112,000,000
Financial liabilities
Other current financial liabilities		44,000,000	68,000,000
Long-term debt, including current portion		6,781,000,000	7,449,000,000
Deferred credits and other financial liabilities		112,000,000	114,000,000
Financial Liabilities Fair Value Disclosure		6,937,000,000	7,631,000,000
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure		754,000,000	7,000,000
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Other noncurrent financial assets		128,000,000	108,000,000
Total financial assets		882,000,000	115,000,000
Financial liabilities
Other current financial liabilities		55,000,000	75,000,000
Long-term debt, including current portion		6,527,000,000	7,292,000,000
Deferred credits and other financial liabilities		105,000,000	107,000,000
Financial Liabilities Fair Value Disclosure		$ 6,687,000,000	$ 7,474,000,000
Oil Sands Mining Segment [Member] | Discontinued Operations, Disposed of by Sale [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of notes receivable	2
International Exploration and Production [Member]
Financial liabilities
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		40.00%