CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2010
Operating activities
Net income	$ 65.7		$ 53.5	[1]	$ 43.2	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	48.0		41.0	[1]	38.7	[1]
Amortization	2.5		2.9	[1]	3.7	[1]
Amortization of deferred financing costs	0.8		0	[1]	0	[1]
Loss on disposal of assets	0		0	[1]	0.9	[1]
Unit-based compensation charges	6.5		0	[1]	0	[1]
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	(3.2)		(2.3)	[1]	(1.5)	[1]
Inventories	(0.4)		(1.0)	[1]	(0.9)	[1]
Prepaid expenses and other current assets	(0.8)		1.1	[1]	6.1	[1]
Other assets	(3.9)		0	[1]	0.7	[1]
Accounts payable and accrued expenses	0.7		(0.2)	[1]	(5.4)	[1]
Bank overdraft	2.4		(0.7)	[1]	0.9	[1]
Payable to Inergy Propane, LLC and Inergy, L.P.	14.4		2.0	[1]	7.9	[1]
Net cash provided by operating activities	132.7		96.3	[1]	94.3	[1]
Investing activities
Acquisitions, net of cash acquired	0		66.8	[1]	0	[1]
Purchases of property, plant and equipment	(220.6)		(98.4)	[1]	(54.7)	[1]
Purchase of US Salt, LLC (Note 9)	(107.7)		0	[1]	0	[1]
Net cash used in investing activities	(328.3)		(165.2)	[1]	(54.7)	[1]
Financing activities
Proceeds from the issuance of long-term debt	509.9		0	[1]	0	[1]
Principal payments on long-term debt	(93.4)		0	[1]	(8.3)	[1]
Equity contributions from parent	0		66.8	[1]	18.3	[1]
Acquisition of minority interest	0		0	[1]	(18.3)	[1]
Distributions to Inergy, L.P.	(163.3)		(7.4)	[1]	(5.9)	[1]
Distributions paid to non-controlling partners	0		0	[1]	(0.6)	[1]
Distributions to shareholders	(14.6)		0	[1]	0	[1]
Principal payment on promissory note	(255.0)		0	[1]	0	[1]
Borrowings from related party	38.8		86.6	[1]	62.4	[1]
Payments to related party	(39.1)		(77.1)	[1]	(90.8)	[1]
Net proceeds from issuance of common units	292.4		0	[1]	0	[1]
Payment for US Salt, LLC in excess of the acquired book value (Note 9)	(74.8)		0	[1]	0	[1]
Other	(0.1)		0	[1]	0	[1]
Payments for deferred financing costs	(5.2)		0	[1]	0	[1]
Net cash provided by (used in) financing activities	195.6		68.9	[1]	(43.2)	[1]
Net increase in cash	0		0	[1]	(3.6)	[1]
Cash at beginning of period	0	[1]	0	[1]	3.6	[1]
Cash at end of period	0		0	[1]	0	[1]
Supplemental disclosure of cash flow information
Cash paid during the period for interest	0.5		0	[1]	0	[1]
Supplemental schedule of non cash investing and financing activities [Abstract]
Net change to property, plant and equipment through accounts payable and accrued expenses	29.6		13.5	[1]	(5.4)	[1]
Net change to property, plant and equipment through non-cash capitalized interest	1.7		8.7	[1]	6.4	[1]
Extinguishment of indebtedness owed to Inergy, L.P.	152.8		0	[1]	0	[1]
Assumption of promissory note of Inergy, L.P. (Note 6)	255.0		0	[1]	0	[1]
Current assets	0		0.5	[1]	0	[1]
Property, plant and equipment	$ 0		$ 66.3	[1]	$ 0	[1]

[1] Retrospectively adjusted as described in Note 1.