Other Required Disclosures - Components of Accounts Payable and Other Current Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2012
Accounts payable and other current liabilities:
Accounts payable	$ 430.6	$ 325.9
Wages and benefits	103.7	110.9
Income taxes payable	46.9	96.6
Accrued interest	61.3	50.4
Accrued expenses	158.9	25.1
Oil and natural gas revenues and royalties payable	16.7
Accrued dividends on Preferred Stock	8.2	8.3
Restructuring and related charges	16.7	6.6
Other	0.4	130.4
Total accounts payable and other current liabilities	$ 843.4	$ 754.2