Other Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Other Income Details [Abstract]
Rental income	$ 21		$ 20	$ 62	$ 59
Net gain on non-operating asset dispositions	11		6	23	11
Interest Income	1		0	2	2
Early extinguishment of debt	0	(2)	0	(2)	0
Non-operating environmental costs and other	(5)		(9)	(20)	(14)
Total	$ 28		$ 17	$ 65	$ 58