Restructuring Charges (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 51	$ 69	$ 128	$ 110
2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	51		128
2016 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	15		20
2016 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	$ 36		$ 108
2015 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		69		110
2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs		50		51
2015 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		$ 19		$ 59