Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified												3 Months Ended		0 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Letters of credit [Member]	Dec. 31, 2012 Surety Bonds [Member]	Dec. 31, 2012 Commitments Expiring Less Than One Year [Member]	Dec. 31, 2012 Commitments Expiring Less Than One Year [Member] Letters of credit [Member]	Dec. 31, 2012 Commitments Expiring Less Than One Year [Member] Surety Bonds [Member]	Dec. 31, 2012 Commitments Expiring More Than One Year [Member]	Dec. 31, 2012 Commitments Expiring More Than One Year [Member] Letters of credit [Member]	Dec. 31, 2012 Commitments Expiring More Than One Year [Member] Surety Bonds [Member]	Dec. 31, 2012 Performance Guarantee [Member] Surety Bonds [Member]	Dec. 31, 2012 Closure Costs [Member] Surety Bonds [Member]	Dec. 31, 2012 Essex EFW Facility [Member] Maximum [Member]	Dec. 31, 2012 Essex EFW Facility [Member] Minimum [Member]	Feb. 28, 2009 Lower Passaic River Study Area [Member] Essex EFW Facility [Member]	Aug. 31, 2004 Lower Passaic River Study Area [Member] Essex EFW Facility [Member]
Loss Contingencies [Line Items]
Number Of Potentially Responsible Parties															71
Loss Contingency, Number of Defendants														300
Other commitments - net	$ 601	$ 256	$ 345	$ 5	$ 5	$ 0	$ 596	$ 251	$ 345	$ 331	$ 14
Expected investment in capital expenditure												$ 100	$ 75