Restructuring Charges (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	$ 41	$ 70
2015 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	41
2015 Plan [Member] | One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	40
2015 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	1
2014 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		70
2014 Plan [Member] | One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0
2014 Plan [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges	0	4
2014 Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance, asset impairment and other restructuring charges		$ 66