Condensed Consolidating Financial Information (Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash	$ 1.6	$ 0.5	$ 8.8	$ 5.2
Accounts receivable	289.8	236.5
Inventory	66.0	44.5
Total current assets	373.4	335.8
Property, plant and equipment, net	2,097.6	3,310.8
Investment in unconsolidated affiliates	1,115.4	254.3
Other assets	6.1	7.2
Total assets	4,448.9	5,762.8
Current liabilities:
Accounts payable	217.2	144.1
Total current liabilities	337.3	258.2
Long-term liabilities:
Long-term debt, less current portion	1,522.7	2,501.8
Other long-term liabilities	44.6	47.5
Deferred income taxes	5.3	8.4
Total partners’ capital	2,539.0	2,946.9	5,584.5	5,508.6
Total liabilities and partners’ capital	4,448.9	5,762.8
Eliminations
Current assets:
Cash	0.0	0.0	0.0	0.0
Accounts receivable	0.0	0.0
Inventory	0.0	0.0
Other	0.0
Total current assets	0.0	0.0
Property, plant and equipment, net	0.0	0.0
Intangible Assets, Net (Including Goodwill)	0.0	0.0
Investment in consolidated affiliates	(4,093.7)	(5,506.8)
Investment in unconsolidated affiliates	0.0	0.0
Other assets	0.0	0.0
Total assets	(4,093.7)	(5,506.8)
Current liabilities:
Accounts payable	0.0	0.0
Total current liabilities	0.0	0.0
Total current liabilities	0.0	0.0
Long-term liabilities:
Long-term debt, less current portion	0.0	0.0
Other long-term liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Partners' capital	(4,093.7)	(5,506.8)
Interest of non-controlling partners in subsidiary	0.0	0.0
Total partners’ capital	(4,093.7)	(5,506.8)
Total liabilities and partners’ capital	(4,093.7)	(5,506.8)
Parent Company, Crestwood Midstream Partners, LP [Member] | Reportable Legal Entities
Current assets:
Cash	1.3	0.1	0.0	0.1
Accounts receivable	0.0	0.0
Inventory	0.0	0.0
Other	0.0	0.0
Total current assets	1.3	0.1
Property, plant and equipment, net	0.0	0.0
Intangible Assets, Net (Including Goodwill)	0.0	0.0
Investment in consolidated affiliates	4,093.7	5,506.8
Investment in unconsolidated affiliates	0.0	0.0
Other assets	0.0	0.0
Total assets	4,095.0	5,506.9
Current liabilities:
Accounts payable	0.0	0.0
Total current liabilities	23.1	26.4
Total current liabilities	23.1	26.4
Long-term liabilities:
Long-term debt, less current portion	1,521.2	2,498.9
Other long-term liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Partners' capital	2,550.7	2,981.6
Interest of non-controlling partners in subsidiary	0.0	0.0
Total partners’ capital	2,550.7	2,981.6
Total liabilities and partners’ capital	4,095.0	5,506.9
Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash	0.0	0.0	7.6	4.0
Accounts receivable	289.3	236.0
Inventory	66.0	44.5
Other	16.0	52.5
Total current assets	371.3	333.0
Property, plant and equipment, net	2,298.4	3,525.7
Intangible Assets, Net (Including Goodwill)	851.9	1,846.9
Investment in consolidated affiliates	0.0	0.0
Investment in unconsolidated affiliates	0.0	0.0
Other assets	1.8	3.1
Total assets	3,523.4	5,708.7
Current liabilities:
Accounts payable	214.5	141.3
Total current liabilities	94.4	85.2
Total current liabilities	308.9	226.5
Long-term liabilities:
Long-term debt, less current portion	1.5	2.9
Other long-term liabilities	42.0	43.3
Deferred income taxes	0.7	0.4
Partners' capital	3,170.3	5,435.6
Interest of non-controlling partners in subsidiary	0.0	0.0
Total partners’ capital	3,170.3	5,435.6
Total liabilities and partners’ capital	3,523.4	5,708.7
Non-Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash	0.0	0.0	0.0	1.0
Accounts receivable	0.5	0.5
Inventory	0.0	0.0
Other	0.0	0.0
Total current assets	0.5	0.5
Property, plant and equipment, net	0.0	0.0
Intangible Assets, Net (Including Goodwill)	0.0	0.0
Investment in consolidated affiliates	0.0	0.0
Investment in unconsolidated affiliates	1,115.4	254.3
Other assets	0.0	0.0
Total assets	1,115.9	254.8
Current liabilities:
Accounts payable	0.0	0.1
Total current liabilities	0.0	0.0
Total current liabilities	0.0	0.1
Long-term liabilities:
Long-term debt, less current portion	0.0	0.0
Other long-term liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Partners' capital	923.4	71.2
Interest of non-controlling partners in subsidiary	192.5	183.5
Total partners’ capital	1,115.9	254.7
Total liabilities and partners’ capital	1,115.9	254.8
CMLP
Current assets:
Cash	1.3	0.1	7.6	5.1
Accounts receivable	289.8	236.5
Inventory	66.0	44.5
Other	16.0	52.5
Total current assets	373.1	333.6
Property, plant and equipment, net	2,298.4	3,525.7
Intangible Assets, Net (Including Goodwill)	851.9	1,846.9
Investment in consolidated affiliates	0.0	0.0
Investment in unconsolidated affiliates	1,115.4	254.3
Other assets	1.8	3.1
Total assets	4,640.6	5,963.6
Current liabilities:
Accounts payable	214.5	141.4
Total current liabilities	117.5	111.6
Total current liabilities	332.0	253.0
Long-term liabilities:
Long-term debt, less current portion	1,522.7	2,501.8
Other long-term liabilities	42.0	43.3
Deferred income taxes	0.7	0.4
Partners' capital	2,550.7	2,981.6
Interest of non-controlling partners in subsidiary	192.5	183.5
Total partners’ capital	2,743.2	3,165.1	$ 5,320.4	$ 5,291.3
Total liabilities and partners’ capital	$ 4,640.6	$ 5,963.6