Long-Term Employee Benefits (Defined Contribution Plan) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Defined Contribution Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contribution		$ 33	$ 57	$ 66
Discontinued Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contribution			32	57
U.S. Defined Contribution Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contribution		$ 187	$ 219	$ 262
US Retirement Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percent of portion of employee's contribution matched by the employer		100.00%
Maximum percent of eligible compensation matched by employer		6.00%
Percent of eligible compensation contributed to defined contribution plan		3.00%
Requisite service period, years		3 years
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan estimated future employer contributions in next fiscal year	about the same