v3.26.1
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, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     $ 307.1  
Equity earnings (loss) $ 7.8 $ 5.1 16.4 $ 10.6
Balance at end of period 317.5   317.5  
Targa Resources Partners LP [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     307.1 193.3
Equity earnings (loss)     16.4 10.6
Cash Distributions     (11.9) (11.1)
Contributions     5.9 [1] 75.8 [2]
Balance at end of period 317.5 268.6 317.5 268.6
Targa Resources Partners LP [Member] | Little Missouri 4 [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     93.7 84.3
Equity earnings (loss)     8.3 7.6
Cash Distributions     (7.6) (9.7)
Contributions     0.3 [1] 5.1 [2]
Balance at end of period 94.7 87.3 94.7 87.3
Targa Resources Partners LP [Member] | Gulf Coast Fractionators LP [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     69.2 66.4
Equity earnings (loss)     (0.4) 0.2
Contributions     1.9 [1] 0.9 [2]
Balance at end of period 70.7 67.5 70.7 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 12.3
Equity earnings (loss)     4.3 3.0
Cash Distributions     (4.3) (1.4)
Balance at end of period 12.3 13.9 12.3 13.9
Targa Resources Partners LP [Member] | Blackcomb [Member]        
Schedule Of Equity Method Investments [Line Items]        
Balance at beginning of period     131.9 30.3
Equity earnings (loss)     4.2 (0.2)
Contributions     3.7 [1] 69.8 [2]
Balance at end of period $ 139.8 $ 99.9 $ 139.8 $ 99.9
[1] Includes capitalized interest of $3.7 million related to our contributions to Blackcomb.
[2] Includes capitalized interest of $1.9 million related to our contributions to Blackcomb.