Debt and Financing Arrangements - Components of Net Financing Charges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Debt Disclosure [Abstract]
Interest expense, net of capitalized interest costs	$ 72	$ 56	$ 143	$ 113
Banking fees and bond cost amortization	6	5	12	9
Interest income	(1)	(2)	(4)	(5)
Net foreign exchange results for financing activities	(8)	(3)	(11)	(6)
Net financing charges	$ 69	$ 56	$ 140	$ 111