Amount paid for premium on extinguishment of debt.

No definition available.

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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

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-Name Accounting Standards Codification
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Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-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))
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Balance Type:	na
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
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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
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Balance Type:	debit
Period Type:	duration

- Definition

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

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Debt Obligations - Senior Unsecured Notes Issuances and Redemptions - Additional Information (Details) - USD ($) $ in Millions			1 Months Ended		6 Months Ended	12 Months Ended
	May 17, 2021	Feb. 22, 2021	Apr. 30, 2021	Feb. 28, 2021	Jun. 30, 2021	Dec. 31, 2020
Senior Unsecured 4¼% Notes due November 2023 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt	4.25%		4.25%
Gain (loss) due to debt extinguishments			$ (1.9)
Maturity date	Nov. 30, 2023		May 17, 2021
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt				5.125%
Gain (loss) due to debt extinguishments				$ (14.9)
Premium Paid				12.5
Write-off debt issuance cost				2.4
Senior Unsecured Notes [Member] \| Senior Unsecured of 4% Senior Notes due 2032 [Member]
Debt Instrument [Line Items]
Aggregate principal amount issued				$ 1,000.0
Interest rate on fixed rate debt				4.00%
Net proceeds from private placement of notes				$ 991.0
Senior Unsecured Notes [Member] \| Targa Pipeline Partners LP [Member] \| Senior Unsecured 5⅞% Notes due August 2023 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt					5.875%	5.875%
Maturity date					Aug. 31, 2023	Aug. 31, 2023
Senior Unsecured Notes [Member] \| Targa Resources Partners LP [Member] \| Senior Unsecured 4¼% Notes due November 2023 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt					4.25%	4.25%
Maturity date					Nov. 30, 2023	Nov. 30, 2023
Senior Unsecured Notes [Member] \| Targa Resources Partners LP [Member] \| Targa Pipeline Partners LP [Member]
Debt Instrument [Line Items]
Gain (loss) due to debt extinguishments		$ 0.2
Senior Unsecured Notes [Member] \| Targa Resources Partners LP [Member] \| Targa Pipeline Partners LP [Member] \| Senior Unsecured 4¾% Notes due November 2021 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt		4.75%
Senior Unsecured Notes [Member] \| Targa Resources Partners LP [Member] \| Targa Pipeline Partners LP [Member] \| Senior Unsecured 5⅞% Notes due August 2023 [Member]
Debt Instrument [Line Items]
Interest rate on fixed rate debt		5.875%