Accounts Payable and Other Current Liabilities - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Accounts Payable and Other Current Liabilities [Abstract]
Accounts Payable	$ 729.1	$ 581.3
Accrued interest	93.0	145.1
Income taxes payable	78.1	68.3
Accrued expenses and other	215.4	188.5
Total accounts payable and other current liabilities	$ 1,115.6	$ 983.2