Condensed Consolidating Financial Information (Statements Of Operations) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Storage and transportation		$ 165.3	$ 266.3	$ 264.6
Related party (Note 16)		2.6	3.9	3.0
Revenues		2,520.5	2,632.8	3,931.3
Costs of product/services sold (exclusive of items shown separately below):
Related party (Note 16)		17.7	28.9	42.2
Total costs of products/services sold		1,925.1	1,883.5	3,165.3
Expenses:
Operations and maintenance		158.1	190.2	203.3
General and administrative		88.2	116.3	100.2
Depreciation, amortization and accretion		229.6	300.1	285.3
Loss on long-lived assets, net		(65.6)	(821.2)	(1.9)
Goodwill impairment		(162.6)	(1,406.3)	(48.8)
Loss on contingent consideration		0.0	0.0	(8.6)
Operating income (loss)		(108.7)	(2,084.8)	117.9
Other income (expense):
Earnings (loss) from unconsolidated affiliates, net		31.5	(60.8)	(0.7)
Interest and debt expense, net		(125.1)	(140.1)	(127.1)
Gain (loss) on modification/extinguishment of debt	$ 10.0	10.0	(20.0)	0.0
Loss before income taxes		(191.8)	(2,305.1)	(9.3)
(Provision) benefit for income taxes		(0.3)	1.4	(1.1)
Net loss		(192.1)	(2,303.7)	(10.4)
Net income attributable to non-controlling partners in subsidiary		24.2	(636.8)	(66.8)
Net income (loss) attributable to parent		(216.3)	(1,666.9)	56.4
Net income attributable to preferred units		28.7	6.2	0.0
Net income (loss) attributable to partners		(245.0)	(1,673.1)	56.4
Eliminations
Revenues:
Revenues		0.0	0.0	0.0
Costs of product/services sold (exclusive of items shown separately below):
Total costs of products/services sold		0.0	0.0	0.0
Expenses:
Operations and maintenance		0.0	0.0	0.0
General and administrative		0.0	0.0	0.0
Depreciation, amortization and accretion		0.0	0.0	0.0
Costs and Expenses		0.0	0.0	0.0
Loss on long-lived assets, net		0.0	0.0	0.0
Goodwill impairment		0.0	0.0	0.0
Loss on contingent consideration				0.0
Operating income (loss)		0.0	0.0	0.0
Other income (expense):
Earnings (loss) from unconsolidated affiliates, net		0.0	0.0	0.0
Interest and debt expense, net		0.0	0.0	0.0
Gain (loss) on modification/extinguishment of debt		0.0	0.0
Loss from unconsolidated affiliates		40.2	1,219.0	(159.6)
Loss before income taxes				(159.6)
(Provision) benefit for income taxes				0.0
Net loss		40.2	1,219.0	(159.6)
Net income attributable to non-controlling partners in subsidiary		0.0	0.0	0.0
Net income (loss) attributable to parent		40.2	1,219.0	(159.6)
Net income attributable to preferred units			0.0	0.0
Net income (loss) attributable to partners			1,219.0	(159.6)
Parent Company, Crestwood Midstream Partners, LP [Member] | Reportable Legal Entities
Revenues:
Revenues		0.0	0.0	0.0
Costs of product/services sold (exclusive of items shown separately below):
Total costs of products/services sold		0.0	0.0	0.0
Expenses:
Operations and maintenance		0.0	0.0	0.0
General and administrative		66.4	65.3	49.4
Depreciation, amortization and accretion		0.0	0.0	0.9
Costs and Expenses		66.4	65.3	50.3
Loss on long-lived assets, net		0.0	0.0	0.0
Goodwill impairment		0.0	0.0	0.0
Loss on contingent consideration				0.0
Operating income (loss)		(66.4)	(65.3)	(50.3)
Other income (expense):
Earnings (loss) from unconsolidated affiliates, net		0.0	0.0	0.0
Interest and debt expense, net		(125.1)	(130.5)	(111.4)
Gain (loss) on modification/extinguishment of debt		10.0	(18.9)
Loss from unconsolidated affiliates		(40.2)	(1,219.0)	159.6
Loss before income taxes				(2.1)
(Provision) benefit for income taxes				0.0
Net loss		(221.7)	(1,433.7)	(2.1)
Net income attributable to non-controlling partners in subsidiary		0.0	0.0	0.0
Net income (loss) attributable to parent		(221.7)	(1,433.7)	(2.1)
Net income attributable to preferred units			(23.1)	17.2
Net income (loss) attributable to partners			(1,456.8)	(19.3)
Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenues		2,520.5	2,632.8	3,917.5
Costs of product/services sold (exclusive of items shown separately below):
Total costs of products/services sold		1,925.1	1,883.5	3,154.8
Expenses:
Operations and maintenance		155.0	188.7	195.4
General and administrative		19.2	40.3	42.3
Depreciation, amortization and accretion		240.5	278.5	254.5
Costs and Expenses		414.7	507.5	492.2
Loss on long-lived assets, net		(65.6)	(227.8)	(35.1)
Goodwill impairment		(162.6)	(1,149.1)	(48.8)
Loss on contingent consideration				(8.6)
Operating income (loss)		(47.5)	(1,135.1)	178.0
Other income (expense):
Earnings (loss) from unconsolidated affiliates, net		0.0	0.0	0.0
Interest and debt expense, net		0.0	0.0	0.0
Gain (loss) on modification/extinguishment of debt		0.0	0.0
Loss from unconsolidated affiliates		0.0	0.0	0.0
Loss before income taxes				178.0
(Provision) benefit for income taxes				(0.9)
Net loss		(47.5)	(1,135.1)	177.1
Net income attributable to non-controlling partners in subsidiary		0.0	0.0	0.0
Net income (loss) attributable to parent		(47.5)	(1,135.1)	177.1
Net income attributable to preferred units			0.0	0.0
Net income (loss) attributable to partners			(1,135.1)	177.1
Non-Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenues		0.0	0.0	0.0
Costs of product/services sold (exclusive of items shown separately below):
Total costs of products/services sold		0.0	0.0	0.0
Expenses:
Operations and maintenance		0.0	0.0	0.0
General and administrative		0.0	0.0	0.0
Depreciation, amortization and accretion		0.0	0.0	0.0
Costs and Expenses		0.0	0.0	0.0
Loss on long-lived assets, net		0.0	0.0	0.0
Goodwill impairment		0.0	0.0	0.0
Loss on contingent consideration				0.0
Operating income (loss)		0.0	0.0	0.0
Other income (expense):
Earnings (loss) from unconsolidated affiliates, net		31.5	(60.8)	(0.7)
Interest and debt expense, net		0.0	0.0	0.0
Gain (loss) on modification/extinguishment of debt		0.0	0.0
Loss from unconsolidated affiliates		0.0	0.0	0.0
Loss before income taxes				(0.7)
(Provision) benefit for income taxes				0.0
Net loss		31.5	(60.8)	(0.7)
Net income attributable to non-controlling partners in subsidiary		24.2	23.1	16.8
Net income (loss) attributable to parent		7.3	(83.9)	(17.5)
Net income attributable to preferred units			0.0	0.0
Net income (loss) attributable to partners			(83.9)	(17.5)
CMLP
Revenues:
Storage and transportation		165.3	266.3	250.8
Related party (Note 16)		2.6	3.9	3.0
Revenues		2,520.5	2,632.8	3,917.5
Costs of product/services sold (exclusive of items shown separately below):
Related party (Note 16)		17.7	28.9	42.2
Total costs of products/services sold		1,925.1	1,883.5	3,154.8
Expenses:
Operations and maintenance		155.0	188.7	195.4
General and administrative		85.6	105.6	91.7
Depreciation, amortization and accretion		240.5	278.5	255.4
Costs and Expenses		481.1	572.8	542.5
Loss on long-lived assets, net		(65.6)	(227.8)	(35.1)
Goodwill impairment		(162.6)	(1,149.1)	(48.8)
Loss on contingent consideration		0.0	0.0	(8.6)
Operating income (loss)		(113.9)	(1,200.4)	127.7
Other income (expense):
Earnings (loss) from unconsolidated affiliates, net		31.5	(60.8)	(0.7)
Interest and debt expense, net		(125.1)	(130.5)	(111.4)
Gain (loss) on modification/extinguishment of debt		10.0	(18.9)	0.0
Loss from unconsolidated affiliates		0.0	0.0	0.0
Loss before income taxes		(197.5)	(1,410.6)	15.6
(Provision) benefit for income taxes		0.0	0.0	(0.9)
Net loss		(197.5)	(1,410.6)	14.7
Net income attributable to non-controlling partners in subsidiary		24.2	23.1	16.8
Net income (loss) attributable to parent		(221.7)	(1,433.7)	(2.1)
Net income attributable to preferred units		0.0	23.1	17.2
Net income (loss) attributable to partners		$ (221.7)	$ (1,456.8)	$ (19.3)