Debt Obligations - Debt Repurchases Summary (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended	12 Months Ended
	Feb. 28, 2021	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Write-off of debt issuance costs	$ (2.4)	$ (2.4)
Gain (loss) from financing activities		$ 63.5	$ (16.6)	$ 45.6	$ (1.4)
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 5⅛% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption				4.4
Premium over face value paid upon redemption			(12.5)		0.0
Write-off of debt issuance costs			(2.4)	(0.1)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 6¾% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Premium over face value paid upon redemption			0.0	(11.1)	0.0
Write-off of debt issuance costs			0.0	(2.6)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 5⅞% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			0.0	7.1	0.0
Write-off of debt issuance costs				(0.2)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 5⅜% Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			0.0	5.3	0.0
Write-off of debt issuance costs			0.0	(0.2)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 5% Senior Notes due 2028 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			0.0	11.7	0.0
Write-off of debt issuance costs			0.0	(0.4)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 6½% Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			0.0	9.3	0.0
Write-off of debt issuance costs			0.0	(0.4)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 6⅞% Senior Notes due 2029 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			0.0	15.5	0.0
Write-off of debt issuance costs			0.0	(0.6)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 5½% Senior Notes due 2030 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			0.0	10.2	0.0
Write-off of debt issuance costs			0.0	(0.5)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 4¼% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Write-off of debt issuance costs			(1.9)	0.0	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 5¼% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Write-off of debt issuance costs			0.0	(1.8)	0.0
Targa Resources Partners LP [Member] | Senior Unsecured Notes [Member] | Partnership 4⅛% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Write-off of debt issuance costs			0.0	0.0	(1.4)
Targa Resources Partners LP [Member] | Targa Pipeline Partners L P | Senior Unsecured Notes [Member] | TPL Notes Due 2021 and 2023 [Member]
Debt Instrument [Line Items]
Discount over face value paid upon redemption			$ 0.2	$ 0.0	$ 0.0