Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Common Share [Line Items]
Net income (loss) attributable to Targa Resources Corp.		$ 193.1	$ 182.2	$ 877.5	$ 384.8
Less: Premium on repurchase of noncontrolling interests, net of tax				53.1
Net income (loss) attributable to common shareholders		$ 193.1	$ 160.4	$ 578.9	$ 319.3
Weighted average shares outstanding - basic		226.6	228.8	227.6	228.6
Dilutive effect of unvested stock awards		3.7	3.3	3.9	3.0
Weighted average shares outstanding - diluted (in shares)		230.3	276.4	231.5	231.6
Net income (loss) per common share - basic		$ 0.85	$ 0.70	$ 2.54	$ 1.40
Net income (loss) per common share - diluted		$ 0.84	$ 0.66	$ 2.50	$ 1.38
Series A Preferred Stock
Earnings Per Common Share [Line Items]
Preferred Stock Dividends Income Statement Impact	[1]		$ 21.8	$ 30.0	$ 65.5
Redeemable Preferred Stock Dividends	[1]			$ 215.5
Dilutive effect of Series A Preferred	[1]		44.3

[1] The Series A Preferred had no mandatory redemption date, but was redeemable at our election for a 5% premium to the liquidation preference subsequent to March 16, 2022. In May 2022, we redeemed all of our issued and outstanding Series A Preferred at a redemption price of $1,050.00 per share, plus $8.87 per share, which is the amount of accrued and unpaid dividends from April 1, 2022 up to, but not including, the redemption date of May 3, 2022. See Note 9 – Preferred Stock for further discussion.