Restructuring Charges (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 49	$ 154	$ 159	$ 283
2015 Plan
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	49		159
2015 Plan | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	9		60
2015 Plan | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	40		99
2014 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		154		283
2014 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		133		164
Asset Impairment Charges		117		138
2014 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		21		119
2014 Plan [Member] | Other Restructuring Less Asset Write-Offs [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		$ 16		$ 26
YEMEN | 2015 Plan | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Asset Impairment Charges	23		23
Other Countries [Member] | 2015 Plan | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Asset Impairment Charges	$ 22		$ 28