Debt Instrument, Basis Spread from Credit Rating

No definition available.

Name:	dpm_DebtInstrumentBasisSpreadfromCreditRating
Namespace Prefix:	dpm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Leverage Ratio

+ References

No definition available.

+ Details

Name:	dpm_DebtInstrumentCovenantLeverageRatio
Namespace Prefix:	dpm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio, Temporary

+ References

No definition available.

+ Details

Name:	dpm_DebtInstrumentCovenantLeverageRatioTemporary
Namespace Prefix:	dpm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Interest Deferment Period

+ References

No definition available.

+ Details

Name:	dpm_DebtInstrumentInterestDefermentPeriod
Namespace Prefix:	dpm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=dpm_AmendedandRestatedCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=dpm_LondonInterbankOfferedRateLIBORMarketIndexMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ProFormaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Additional Information (Detail)	12 Months Ended
Debt - Additional Information (Detail)	Dec. 31, 2016 USD ($)	May 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($)	Feb. 28, 2015 USD ($)
Debt Instrument [Line Items]
Unamortized issuance costs	$ 23,000,000			$ 35,000,000
Letters of credit outstanding	$ 13,000,000
Interest deferment period	5 years
Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,250,000,000.00	$ 700,000,000	$ 1,800,000,000.0		$ 1,800,000,000	$ 2,000,000,000
Unamortized issuance costs	$ 10,000,000
Basis spread determined by credit rating	0.45%
Commitment fee percentage	0.30%
Unused capacity under the credit agreement	$ 1,031,000,000
Letters of credit outstanding	$ 24,000,000
Amended and Restated Credit Agreement \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Variable rate basis spread	1.45%
Amended and Restated Credit Agreement \| Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Variable rate basis spread	0.50%
Amended and Restated Credit Agreement \| London Interbank Offered Rate (LIBOR) Market Index [Member]
Debt Instrument [Line Items]
Variable rate basis spread	1.00%
Amended and Restated Credit Agreement \| Minimum
Debt Instrument [Line Items]
Maximum leverage ratio	1.0
Temporary maximum leverage ratio post-acquisition	1.0
Amended and Restated Credit Agreement \| Maximum
Debt Instrument [Line Items]
Maximum leverage ratio	5.0
Temporary maximum leverage ratio post-acquisition	5.5
Amended and Restated Credit Agreement \| Pro Forma
Debt Instrument [Line Items]
Unused capacity under the credit agreement	$ 970,000,000