CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income (loss) attributable to Targa Resources Corp.	$ (187.3)	$ 58.3	$ 102.3
Interest rate swaps:
Change in fair value, pre-tax	0.0	0.0	0.0
Change in fair value, related income tax	0.0	0.0	0.0
Change in fair value, after tax	0.0	0.0	0.0
Settlements reclassified to interest expense, net, pre-tax	0.0	0.0	0.3
Settlements reclassified to interest expense, net, related income tax	0.0	0.0	(0.1)
Settlements reclassified to interest expense, net, after tax	0.0	0.0	0.2
Other comprehensive income (loss) attributable to Targa Resources Corp., pre-tax	(161.1)	1.5	8.4
Other comprehensive income (loss) attributable to Targa Resources Corp., related income tax	61.3	(0.6)	(3.1)
Other comprehensive income (loss) attributable to Targa Resources Corp., after tax	(99.8)	0.9	5.3
Comprehensive income (loss) attributable to Targa Resources Corp.	(287.1)	59.2	107.6
Net income (loss) attributable to noncontrolling interests	28.2	(209.7)	320.7
Interest rate swaps:
Change in fair value, pre-tax	0.0	0.0	0.0
Change in fair value, related income tax	0.0	0.0	0.0
Change in fair value, after tax	0.0	0.0	0.0
Settlements reclassified to interest expense, net, pre-tax	0.0	0.0	2.1
Settlements reclassified to interest expense, net, related income tax	0.0	0.0	0.0
Settlements reclassified to interest expense, net, after tax	0.0	0.0	2.1
Other comprehensive income (loss) attributable to noncontrolling interests, pre-tax	12.5	24.9	57.9
Other comprehensive income (loss) attributable to noncontrolling interests, related income tax	0.0	0.0	0.0
Other comprehensive income (loss) attributable to noncontrolling interests, after tax	12.5	24.9	57.9
Comprehensive income (loss) attributable to noncontrolling interests	40.7	(184.8)	378.6
Total
Net income (loss)	(159.1)	(151.4)	423.0
Interest rate swaps:
Change in fair value, pre-tax	0.0	0.0	0.0
Change in fair value, related income tax	0.0	0.0	0.0
Change in fair value, after tax	0.0	0.0	0.0
Settlements reclassified to interest expense, net, pre-tax	0.0	0.0	2.4
Settlements reclassified to interest expense, net, related income tax	0.0	0.0	(0.1)
Settlements reclassified to interest expense, net, after tax	0.0	0.0	2.3
Other comprehensive income (loss) attributable to Targa Resources Corp., pre-tax	(148.6)	26.4	66.3
Other comprehensive income (loss) attributable to Targa Resources Corp., related income tax	61.3	(0.6)	(3.1)
Other comprehensive income (loss) attributable to Targa Resources Corp., after tax	(87.3)	25.8	63.2
Total comprehensive income (loss)	(246.4)	(125.6)	486.2
Commodity Contracts [Member]
Commodity hedging contracts:
Change in fair value, pre-tax	(127.3)	11.0	7.5
Change in fair value, related income tax	48.5	(4.2)	(2.9)
Change in fair value, after tax	(78.8)	6.8	4.6
Settlements reclassified to revenues, pre-tax	(33.8)	(9.5)	0.6
Settlements reclassified to revenues, related income tax	12.8	3.6	(0.1)
Settlements reclassified to revenues, after tax	(21.0)	(5.9)	0.5
Commodity hedging contracts:
Change in fair value, pre-tax	23.7	101.7	52.2
Change in fair value, related income tax	0.0	0.0	0.0
Change in fair value, after tax	23.7	101.7	52.2
Settlements reclassified to revenues, pre-tax	(11.2)	(76.8)	3.6
Settlements reclassified to revenues, related income tax	0.0	0.0	0.0
Settlements reclassified to revenues, after tax	(11.2)	(76.8)	3.6
Commodity hedging contracts:
Change in fair value, pre-tax	(103.6)	112.7	59.7
Change in fair value, related income tax	48.5	(4.2)	(2.9)
Change in fair value, after tax	(55.1)	108.5	56.8
Settlements reclassified to revenues, pre-tax	(45.0)	(86.3)	4.2
Settlements reclassified to revenues, related income tax	12.8	3.6	(0.1)
Settlements reclassified to revenues, after tax	$ (32.2)	$ (82.7)	$ 4.1