Other Expenses (Restructuring Charges) (Details) (Other Expenses [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 46	$ 23
Restructuring charges	13	33
Cash payments	(30)	(36)
Balance, end of period	29	20
Total restructuring charges incurred since inception of initiative	287	192
Severance [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	40	23
Restructuring charges	12	30
Cash payments	(28)	(33)
Balance, end of period	24	20
Total restructuring charges incurred since inception of initiative	252	171
Lease and Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	6	0
Restructuring charges	1	3
Cash payments	(2)	(3)
Balance, end of period	5	0
Total restructuring charges incurred since inception of initiative	$ 35	$ 21