Other Expenses (Restructuring Charges) (Details) (Other Expenses [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 29	$ 20	$ 46	$ 23
Restructuring charges	18	16	31	49
Cash payments	(24)	(15)	(54)	(51)
Balance, end of period	23	21	23	21
Total restructuring charges incurred since inception of initiative	306	208	306	208
Severance [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	24	20	40	23
Restructuring charges	14	7	26	37
Cash payments	(22)	(15)	(50)	(48)
Balance, end of period	16	12	16	12
Total restructuring charges incurred since inception of initiative	267	178	267	178
Lease and Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	5	0	6	0
Restructuring charges	4	9	5	12
Cash payments	(2)	0	(4)	(3)
Balance, end of period	7	9	7	9
Total restructuring charges incurred since inception of initiative	$ 39	$ 30	$ 39	$ 30