Other Expenses (Other Restructuring Charges) (Details) (Other Expenses [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 21	$ 21	$ 23	$ 0
Restructuring charges	16	54	65	101
Cash payments	(17)	(40)	(68)	(66)
Balance, end of period	20	35	20	35
Total restructuring charges incurred since inception of initiative			224	101
Severance [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	12	21	23	0
Restructuring charges	14	46	51	93
Cash payments	(13)	(40)	(61)	(66)
Balance, end of period	13	27	13	27
Total restructuring charges incurred since inception of initiative			192	93
Lease and Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	9	0	0	0
Restructuring charges	2	8	14	8
Cash payments	(4)	0	(7)	0
Balance, end of period	7	8	7	8
Total restructuring charges incurred since inception of initiative			$ 32	$ 8