Name:	trgp_LeverageRatioForEachFiscalQuarterAfterYearOne
Namespace Prefix:	trgp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

The ratio of consolidated funded indebtedness to consolidated adjusted EBITDA for each fiscal quarter in the first year of the credit agreement.

No definition available.

Name:	trgp_LeverageRatioForEachFiscalQuarterInYearOne
Namespace Prefix:	trgp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

The additional commitment increase under the credit facility available upon request.

No definition available.

Name:	trgp_LineOfCreditAdditionalCommitmentIncreaseAvailableUponRequest
Namespace Prefix:	trgp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Revolving loans leverage ratio.

No definition available.

Name:	trgp_RevolvingLoansLeverageRatio
Namespace Prefix:	trgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Term loans leverage ratio.

No definition available.

Name:	trgp_TermLoansLeverageRatio
Namespace Prefix:	trgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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

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.

No definition available.

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

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120391452&loc=d3e13212-122682

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

Name:	us-gaap_DebtInstrumentAxis=trgp_TRCRevolverMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=trgp_TRCSeniorSecuredRevolvingCreditFacilityDue2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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