v3.25.2
Investments in Unconsolidated Affiliates - Activity Related to Partnership's Investments in Unconsolidated Affiliates (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     $ 193.3  
Equity earnings (loss) $ 5.1 $ 2.9 10.6 $ 5.6
Balance at end of period 268.6   268.6  
Targa Resources Partners LP [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     193.3  
Equity earnings (loss)     10.6  
Cash Distributions     (11.1)  
Contributions [1]     75.8  
Balance at end of period 268.6   268.6  
Targa Resources Partners LP [Member] | Little Missouri 4 [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     84.3  
Equity earnings (loss)     7.6  
Cash Distributions     (9.7)  
Contributions [1]     5.1  
Balance at end of period 87.3   87.3  
Targa Resources Partners LP [Member] | Gulf Coast Fractionators LP [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     66.4  
Equity earnings (loss)     0.2  
Contributions [1]     0.9  
Balance at end of period 67.5   67.5  
Targa Resources Partners LP [Member] | Cayenne Joint Venture [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     12.3  
Equity earnings (loss)     3.0  
Cash Distributions     (1.4)  
Balance at end of period 13.9   13.9  
Targa Resources Partners LP [Member] | Blackcomb [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     30.3  
Equity earnings (loss)     (0.2)  
Contributions [1]     69.8  
Balance at end of period $ 99.9   $ 99.9  
[1] Includes capitalized interest of $1.9 million related to our contributions to Blackcomb.