Interest coverage ratio.

No definition available.

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

- Definition

Leverage ratio before collateral release date.

+ References

No definition available.

+ Details

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

- Definition

Leverage ratio upon and after collateral release date.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Maximum percentage of consolidated EBITDA.

+ References

No definition available.

+ Details

Name:	trgp_MaximumPercentageOfConsolidatedEBITDA
Namespace Prefix:	trgp_
Data Type:	dtr-types:percentItemType
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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- 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

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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:	dtr-types: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://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

+ Details

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

- Details

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

- Details

Name:	us-gaap_TypeOfArrangementAxis=trgp_FirstAmendmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=trgp_FederalFundsRateMember
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:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=trgp_NonCreditEnhancedSeniorUnsecuredLongTermDebtRatingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

Debt Obligations - Existing TRP Revolver - Additional Information (Details) - Existing TRP Revolver [Member]			1 Months Ended	12 Months Ended
	Jul. 01, 2020	Feb. 17, 2016	Jun. 29, 2019	Dec. 31, 2021 USD ($)	Jun. 30, 2020
Debt Instrument [Line Items]
Maturity date				Jun. 30, 2023
Maximum borrowing capacity				$ 2,200,000,000
Line Of Credit Additional Commitment Increase Available Upon Request				$ 500,000,000.0
First Amendment [Member]
Debt Instrument [Line Items]
Maximum percentage of consolidated EBITDA	20.00%		20.00%		30.00%
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				0.50%
London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate				1.00%
Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage				0.25%
Leverage ratio before collateral release date				1.00
Leverage ratio upon and after collateral release date		1.00		1.00
Interest coverage ratio				1.00
Minimum [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt				1.25%
Minimum [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member]
Debt Instrument [Line Items]
Commitment fee percentage				0.125%
Minimum [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt				1.125%
Minimum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				0.25%
Minimum [Member] \| Base Rate [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				0.125%
Minimum [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				1.25%
Minimum [Member] \| Eurodollar [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				1.125%
Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage				0.375%
Leverage ratio before collateral release date				5.50
Leverage ratio upon and after collateral release date		5.50		5.25
Interest coverage ratio				2.25
Aggregate principal amount issued				$ 400,000,000.0
Maximum [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt				2.25%
Maximum [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member]
Debt Instrument [Line Items]
Commitment fee percentage				0.35%
Maximum [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt				1.75%
Maximum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				1.25%
Maximum [Member] \| Base Rate [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				0.75%
Maximum [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				2.25%
Maximum [Member] \| Eurodollar [Member] \| Non-Credit-Enhanced Senior Unsecured Long-Term Debt Ratings [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				1.75%