Debt instrument repurchased amount book value.

No definition available.

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

- Definition

Interest and debt income expense.

+ References

No definition available.

+ Details

Name:	trgp_InterestAndDebtIncomeExpense
Namespace Prefix:	trgp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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 https://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 https://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 https://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 https://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 https://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 https://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 https://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 https://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 https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

+ Details

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

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

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

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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

- Definition

Amount of gain (loss) from the difference between the repurchase price of a debt instrument initially issued by the entity and the net carrying amount of the debt at the time of its repurchase.

+ References

No definition available.

+ Details

Name:	us-gaap_GainLossOnRepurchaseOfDebtInstrument
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=126972273&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126972273&loc=d3e12317-112629

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromDebtNetOfIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

+ Details

Name:	us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=trgp_SeniorUnsecuredNotesDueMarch2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=trgp_SeniorUnsecuredNotesDueMay2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=trgp_SeniorUnsecuredNotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=trgp_SeniorUnsecuredNotesDueNovember2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=trgp_SeniorUnsecuredNotesDueFebruary2033Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	dei_LegalEntityAxis=trgp_TargaResourcesPartnersLpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=trgp_TargaPipelinePartnersLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=trgp_SeniorUnsecuredNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt Obligations - Debt Repurchases & Extinguishments - Additional Information (Details) - USD ($) $ in Millions		1 Months Ended					6 Months Ended	12 Months Ended
	Sep. 01, 2020	Jan. 31, 2023	Feb. 28, 2022	Apr. 30, 2021	Feb. 28, 2021	Nov. 30, 2020	Jun. 30, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jul. 31, 2022	Apr. 30, 2022	Aug. 31, 2020
Debt Instrument [Line Items]
Debt repurchased, payment							$ 239.8
Debt repurchased, book value							303.3
Gain (loss) from financing activities							$ 61.1	$ (49.6)	$ (16.6)	$ 45.6
Debt repurchased, gain								(49.6)	$ (16.6)	45.6
Gain (loss) due to debt extinguishments					$ (14.9)
Senior Unsecured 6.750% Notes due March 2024 [Member]
Debt Instrument [Line Items]
Face amount of notes redeemed	$ 318.0												$ 262.1
Gain (loss) due to debt extinguishments	$ (13.7)
Senior Unsecured 5.250% Notes due May 2023 [Member]
Debt Instrument [Line Items]
Face amount of notes redeemed						$ 559.6
Gain (loss) due to debt extinguishments			$ 0.8			$ (1.8)
Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Gain (loss) due to debt extinguishments								$ 33.8
Maturity date			Mar. 31, 2022
TRGP Revolver [Member]
Debt Instrument [Line Items]
Gain (loss) due to debt extinguishments			$ 15.0
Senior Unsecured 4.250% Notes due November 2023 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt				4.25%
Gain (loss) due to debt extinguishments				$ (1.9)
Maturity date				May 31, 2021
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt					5.125%							4.20%
Senior Unsecured Notes [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Net proceeds from private placement of notes		$ 1,700.0
Senior Unsecured Notes [Member] \| Senior Unsecured 6.750% Notes due March 2024 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt	6.75%												6.75%
Senior Unsecured Notes [Member] \| Senior Unsecured 5.250% Notes due May 2023 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt						5.25%
Senior Unsecured Notes [Member] \| Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt											5.20%
Senior Unsecured Notes [Member] \| Senior Unsecured Notes Due February2033 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt								4.20%	4.20%			4.20%
Maturity date								Feb. 28, 2033	Feb. 28, 2033
Aggregate principal amount issued												$ 750.0
Senior Unsecured Notes [Member] \| Senior Unsecured 6.500% Notes due 2053 [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt		6.50%
Aggregate principal amount issued		$ 850.0
Targa Resources Partners LP [Member] \| Targa Pipeline Partners L P
Debt Instrument [Line Items]
Gain (loss) due to debt extinguishments					$ 0.2
Targa Resources Partners LP [Member] \| Senior Notes due 2027 [Member] \| Targa Pipeline Partners L P
Debt Instrument [Line Items]
Interest rate on fixed rate debt			5.375%
Targa Resources Partners LP [Member] \| Senior Unsecured 4.200% Notes due 2027 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt			4.20%
Targa Resources Partners LP [Member] \| Senior Unsecured 4.950% Notes due 2027 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt			4.95%
Targa Resources Partners LP [Member] \| Senior Unsecured 5.875% Notes due 2027 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt			5.875%
Targa Resources Partners LP [Member] \| Senior Unsecured 5.875% Notes due August 2023 [Member] \| Targa Pipeline Partners L P
Debt Instrument [Line Items]
Interest rate on fixed rate debt					5.875%
Targa Resources Partners LP [Member] \| Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Write-off debt issuance cost								$ 0.0	$ 0.0	$ 1.8