Environmental Matters (Environmental Remediation Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Environmental Matters [Abstract]
Remediation costs incurred	$ 39	$ 39
Insurance recoveries received		$ 1	[1]

[1] Reduced amount deferred for recovery from customers