Restructuring Costs (Restructuring Activities) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Restructuring Reserve [Roll Forward]
Liability at beginning of period	$ 124	$ 170
Amounts Accrued	6	22
Cash Paid	(20)	(65)
Other	(1)	(3)
Liability at end of period	109	124
Severance [Member]
Restructuring Reserve [Roll Forward]
Liability at beginning of period	11	36
Amounts Accrued	2	9
Cash Paid	(5)	(33)
Other		(1)
Liability at end of period	8	11
Future Rent Under Non-Cancelable Leases and Other Costs [Member]
Restructuring Reserve [Roll Forward]
Liability at beginning of period	113	134
Amounts Accrued	4	13
Cash Paid	(15)	(32)
Other	(1)	(2)
Liability at end of period	101	113
Corporate Segment [Member]
Restructuring Reserve [Roll Forward]
Amounts Accrued	$ 6