AmeriGas Merger and Acquisitions - Narrative (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Aug. 21, 2019 USD ($) $ / shares shares	Aug. 01, 2019 USD ($) shares	Sep. 30, 2019 USD ($) shares	Sep. 30, 2018 USD ($) propane_distribution_business	Sep. 30, 2017 USD ($)
Total cash paid			$ 528.9	$ 0.0	$ 0.0
Merger Sub
Total cash paid	$ 528.9
Incentive distribution, distribution	2,227.7
After tax transaction costs	7.7
Operating expenses	6.3
Deferred tax asset, step up in tax basis of the underlying assets	$ 512.3		$ 512.3
Merger Sub | Common Stock
Consideration paid (in shares) | shares	34,612,847	34,612,847	34,613,000
CMG
Total cash paid		$ 1,284.4
After tax transaction costs		$ 15.3
Merger Agreement, Proposed Consideration One | Merger Sub | Common Stock
Business combination, consideration transferred, equity interests issuable per acquiree share (in shares) | shares	0.500
Merger Agreement, Proposed Consideration Two | Merger Sub | Common Stock
Business combination, consideration transferred, equity interests issuable per acquiree share (in shares) | shares	0.6378
Merger Agreement, Proposed Consideration Two | Merger Sub | Cash Without Interest
Business combination, consideration transferred, equity interests issuable per share (in dollars per share) | $ / shares	$ 7.63
Merger Agreement, Proposed Consideration Three | Merger Sub | Cash Without Interest
Business combination, consideration transferred, equity interests issuable per share (in dollars per share) | $ / shares	$ 35.325
AmeriGas Propane
Total cash paid				10.1	36.8
Incentive distribution, distribution				$ 12.8	$ 47.6
Number of retail propane distribution businesses acquired | propane_distribution_business				2
Affiliated Entity | CMG | Pennant
Percentage of voting interests acquired		47.00%