Supplementary Information - Condensed Consolidating Financial Information (Condensed Consolidating Statement Of Cash Flows) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$ 158.8	[1]	$ 181.0	[2]
INVESTING ACTIVITIES:
Capital expenditures	(152.5)	[1]	(98.5)	[2]
Acquisitions, net of cash acquired	(375.4)	[1]	(174.9)	[2]
Acquisitions of unconsolidated affiliates	(29.8)	[1]	(114.3)
Investments in unconsolidated affiliates	(86.3)	[1]	(6.8)	[2]
Return of investment in unconsolidated affiliates	1.0	[1]	1.6	[2]
Proceeds from sale of assets	0.2	[1]	0.2	[2]
Net cash used in investing activities	(642.8)	[1]	(278.4)	[2]
FINANCING ACTIVITIES:
Proceeds from debt	1,353.4	[1]	832.0	[2]
Payments of debt	(1,062.0)	[1]	(754.0)	[2]
Payment of deferred financing costs	(3.5)	[1]	(0.1)	[2]
Proceeds from issuance of common units, net of offering cost	445.2	[1]	152.0	[2]
Net change in advances to predecessor from DCP Midstream, LLC	(11.5)	[1]	14.6	[2]
Distributions to unitholders and general partner	(128.7)	[1]	(97.5)	[2]
Distributions to noncontrolling interests	(4.8)	[1]	(26.8)	[2]
Net cash provided by (used in) financing activities	484.8	[1]	93.6	[2]
Net change in cash and cash equivalents	0.8	[1]	(3.8)	[2]
Cash and cash equivalents, beginning of period	7.6	[1],[3]	6.7	[2]
Cash and cash equivalents, end of period	8.4	[1]	2.9	[2]
Cash Portion [Member]
FINANCING ACTIVITIES:
Excess purchase price over acquired assets	(110.2)	[1]	(35.7)	[2]
Contributions from DCP Midstream, LLC	6.9	[1]	9.1	[2]
DCP Midstream Partners, LP [Member]
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	(316.5)	[1]	(54.5)	[2]
FINANCING ACTIVITIES:
Proceeds from issuance of common units, net of offering cost	445.2	[1]	152.0	[2]
Distributions to unitholders and general partner	(128.7)	[1]	(97.5)	[2]
Net cash provided by (used in) financing activities	316.5	[1]	54.5	[2]
Subsidiary Issuer [Member]
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	(285.1)	[1]	(77.3)	[2]
FINANCING ACTIVITIES:
Proceeds from debt	1,353.4	[1]	832.0	[2]
Payments of debt	(1,062.0)	[1]	(754.0)	[2]
Payment of deferred financing costs	(3.5)	[1]	(0.1)	[2]
Net change in short-term borrowings	0.1	[1]
Net cash provided by (used in) financing activities	288.0	[1]	77.9	[2]
Net change in cash and cash equivalents	2.9	[1]	0.6	[2]
Cash and cash equivalents, beginning of period	3.6	[1],[3]	1.5	[2]
Cash and cash equivalents, end of period	6.5	[1]	2.1	[2]
Non-Guarantor Subsidiaries [Member]
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	757.9	[1]	313.2	[2]
INVESTING ACTIVITIES:
Capital expenditures	(152.5)	[1]	(98.5)	[2]
Acquisitions, net of cash acquired	(375.4)	[1]	(174.9)	[2]
Acquisitions of unconsolidated affiliates	(29.8)	[1]
Investments in unconsolidated affiliates	(86.3)	[1]	(6.8)	[2]
Return of investment in unconsolidated affiliates	1.0	[1]	1.6	[2]
Proceeds from sale of assets	0.2	[1]	0.2	[2]
Net cash used in investing activities	(642.8)	[1]	(278.4)	[2]
FINANCING ACTIVITIES:
Net change in advances to predecessor from DCP Midstream, LLC	(11.5)	[1]	14.6	[2]
Distributions to noncontrolling interests	(4.8)	[1]	(26.8)	[2]
Net cash provided by (used in) financing activities	(119.6)	[1]	(38.8)	[2]
Net change in cash and cash equivalents	(4.5)	[1]	(4.0)	[2]
Cash and cash equivalents, beginning of period	6.4	[1],[3]	6.7	[2]
Cash and cash equivalents, end of period	1.9	[1]	2.7	[2]
Non-Guarantor Subsidiaries [Member] | Cash Portion [Member]
FINANCING ACTIVITIES:
Excess purchase price over acquired assets	(110.2)	[1]	(35.7)	[2]
Contributions from DCP Midstream, LLC	6.9	[1]	9.1	[2]
Consolidating Adjustments [Member]
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	2.5	[1]	(0.4)	[2]
FINANCING ACTIVITIES:
Net change in short-term borrowings	(0.1)	[1]
Net cash provided by (used in) financing activities	(0.1)	[1]
Net change in cash and cash equivalents	2.4	[1]	(0.4)	[2]
Cash and cash equivalents, beginning of period	(2.4)	[1],[3]	(1.5)	[2]
Cash and cash equivalents, end of period			$ (1.9)	[2]

[1] The financial information for the nine months ended September 30, 2012 includes the results of Southeast Texas, a transfer of net assets between entities under common control that was accounted for as if the transfer occurred at the beginning of the period, and prior years are retrospectively adjusted to furnish comparative information similar to the pooling method.

[2] The financial information during the nine months ended September 30, 2011 includes the results of Southeast Texas, a transfer of net assets between entities under common control that was accounted for as if the transfer occurred at the beginning of the period, and prior years are retrospectively adjusted to furnish comparative information similar to the pooling method.

[3] The financial information as of December 31, 2011 includes the results of Southeast Texas, a transfer of net assets between entities under common control that was accounted for as if the transfer occurred at the beginning of the period, and prior years are retrospectively adjusted to furnish comparative information similar to the pooling method.