Noncurrent Other Liabilities (Schedule of Changes in Asset Retirement Obligations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Other Liabilities, Noncurrent [Abstract]
Balance at beginning of year	$ 47		$ 64		$ 64
Additions	4	[1]	5	[1]	3	[1]
Accretion	1		2		3
Payments	(8)		(23)		(12)
Revisions to cash flow estimates	(7)	[2]	(2)	[2]	5	[2]
Exchange rate changes	0		1		1
Balance at end of year	$ 37		$ 47		$ 64

[1] Primarily relates to sites which management no longer considers to have an indeterminate life.

[2] Primarily relates to revisions to the estimated cost and timing of future obligations.