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Investments in Unconsolidated Affiliates - Activity Related to Partnership's Investments in Unconsolidated Affiliates (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period $ 146.3    
Equity earnings (loss) 9.4 $ 9.0 $ 9.1
Balance at end of period 193.3 146.3  
Targa Resources Partners LP [Member]      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period 146.3 131.3 586.5
Equity earnings (loss) 9.4 9.0 9.1
Cash Distributions (25.3) (18.6) (29.0)
Disposition/ Consolidation     (436.8)
Contributions 62.9 24.6 1.5
Balance at end of period 193.3 146.3 131.3
Targa Resources Partners LP [Member] | GCX [Member]      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period     421.0
Equity earnings (loss)     5.7
Cash Distributions     (14.3)
Disposition/ Consolidation     (412.4)
Targa Resources Partners LP [Member] | Little Missouri 4 [Member]      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period 87.1 90.7 98.1
Equity earnings (loss) 14.4 7.7 5.5
Cash Distributions (17.2) (11.3) (12.9)
Balance at end of period 84.3 87.1 90.7
Targa Resources Partners LP [Member] | T2 Eagle Ford      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period [1]     21.9
Equity earnings (loss) [1]     (0.6)
Cash Distributions [1]     (0.8)
Disposition/ Consolidation [1]     (20.5)
Targa Resources Partners LP [Member] | T2 La Salle      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period [1]     4.2
Equity earnings (loss) [1]     (0.3)
Disposition/ Consolidation [1]     (3.9)
Targa Resources Partners LP [Member] | Gulf Coast Fractionators LP [Member]      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period [2] 45.6 27.1 28.8
Equity earnings (loss) [2] (11.8) (4.1) (3.2)
Cash Distributions [2]   (2.0)  
Contributions [2] 32.6 24.6 1.5
Balance at end of period [2] 66.4 45.6 27.1
Targa Resources Partners LP [Member] | Cayenne Joint Venture [Member]      
Schedule Of Equity Method Investments [Line Items]      
Balance at beginning of period 13.6 13.5 12.5
Equity earnings (loss) 6.8 5.4 2.0
Cash Distributions (8.1) (5.3) (1.0)
Balance at end of period 12.3 $ 13.6 $ 13.5
Targa Resources Partners LP [Member] | Blackcomb [Member]      
Schedule Of Equity Method Investments [Line Items]      
Contributions 30.3    
Balance at end of period $ 30.3    
[1] Following the closing of the South Texas Acquisition in April 2022, the T2 Joint Ventures are 100% owned and consolidated by Targa.
[2] In January 2021, the GCF facility was temporarily idled and Targa assumed operatorship in the first half of 2021. In January 2023, we reached an agreement with our partners to reactivate the GCF facility. We expect the reactivation of GCF to be complete and the facility to be operational in the first quarter of 2025.