Revenue Recognition - Summary of Opening and Closing Balances of Contract Assets and Contract Liabilities (Details) $ in Millions	6 Months Ended
	Mar. 31, 2022 USD ($)
Disaggregation of Revenue [Abstract]
Short-Term Contract Assets, Beginning balance	$ 199.1
Increase in Short-Term Contract Assets	32.6
Short-Term Contract Assets, Ending balance	231.7
Short-Term Contract Liabilities, Beginning balance	12.8
Increase in Short-Term Contract Liabilities	4.7
Short-Term Contract Liabilities, Ending balance	$ 17.5