Contingencies (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Mar. 31, 2015
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 19
Payments and other	(3)
Accruals	0
Ending balance	16
Superfund Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	2
Payments and other	0
Accruals	0
Ending balance	2
Non-Superfund Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17
Payments and other	(3)
Accruals	0
Ending balance	$ 14