Other Expenses (Restructuring Charges) (Details) (Other Expenses [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Balance at January 1,	$ 45	$ 22	$ 0
Restructuring charges	74	103	119
Cash payments	(82)	(80)	(97)
Balance at December 31,	37	45	22
Total restructuring charges incurred since inception of initiative	296	222	119
Severance
Restructuring Reserve [Roll Forward]
Balance at January 1,	39	22	0
Restructuring charges	66	87	101
Cash payments	(74)	(70)	(79)
Balance at December 31,	31	39	22
Total restructuring charges incurred since inception of initiative	254	188	101
Lease and Asset Impairment
Restructuring Reserve [Roll Forward]
Balance at January 1,	6	0	0
Restructuring charges	8	16	18
Cash payments	(8)	(10)	(18)
Balance at December 31,	6	6	0
Total restructuring charges incurred since inception of initiative	$ 42	$ 34	$ 18