Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the declared dividend will be paid, in YYYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-3

+ Details

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

- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

+ References

+ Details

Name:	us-gaap_DividendsCommonStockCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_DividendsPayableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of paid and unpaid cash, stock, and paid-in-kind dividends declared for award under share-based payment arrangement.

+ References

No definition available.

+ Details

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

- Definition

Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

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

- Details

Name:	us-gaap_DividendsAxis=trgp_O2025Q1DividendsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=trgp_O2024Q4DividendsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=trgp_O2025Q2DividendsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Common Stock and Related Matters - Dividends Declared And Or Paid (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Dividends Payable [Line Items]
Dividends Declared per Share of Common Stock	$ 1			$ 0.75	$ 1.75	$ 1.25
Quarterly Cash Dividend Q1 2025 [Member]
Dividends Payable [Line Items]
Date Paid or To Be Paid		May 15, 2025
Total Common Dividends Declared		$ 219.0
Amount of Common Dividends Paid or To Be Paid		216.9
Dividends on Share-Based Awards		$ 2.1
Dividends Declared per Share of Common Stock		$ 1
Quarterly Cash Dividend Q4 2024 [Member]
Dividends Payable [Line Items]
Date Paid or To Be Paid			Feb. 14, 2025
Total Common Dividends Declared			$ 165.2
Amount of Common Dividends Paid or To Be Paid			163.6
Dividends on Share-Based Awards			$ 1.6
Dividends Declared per Share of Common Stock			$ 0.75
Quarterly Cash Dividend Q2 2025 [Member]
Dividends Payable [Line Items]
Date Paid or To Be Paid	Aug. 15, 2025
Total Common Dividends Declared	$ 217.1
Amount of Common Dividends Paid or To Be Paid	215.2
Dividends on Share-Based Awards	$ 1.9
Dividends Declared per Share of Common Stock	$ 1