Commitments And Contingent Liabilities (Accrued Liability For Environmental Remediation Classified In The Balance Sheet) (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010	Dec. 31, 2009
Loss Contingencies [Line Items]
Environmental remediation liability	$ 118	$ 115	$ 119	$ 116
Accrued Liabilities [Member]
Loss Contingencies [Line Items]
Environmental remediation liability	30	29
Other Deferred Credits And Liabilities [Member]
Loss Contingencies [Line Items]
Environmental remediation liability	$ 88	$ 86