Revenue Recognition (Contract Assets and Liabilities) (Details) - USD ($) $ in Millions	6 Months Ended
Mar. 31, 2019	Oct. 01, 2018
Contract Assets and Liabilities
Contract assets - current	$ 34.6	$ 53.0
Contract fulfillment costs - current	65.9	50.7
Contract liabilities - current	194.2	174.5
Contract liabilities - noncurrent	50.2	$ 53.5
Revenue recognized that was previously included in current contract liabilities	$ 75.0

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as current.

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-Name Accounting Standards Codification
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- References

No definition available.

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- Definition

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

+ References

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- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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