Derivative Instruments and Hedging Activities - Notional Volumes Of The Partnership's Commodity Derivative Contracts (Details) - Targa Resources Partners LP [Member]	9 Months Ended
	Sep. 30, 2018 MMBTU bbl
Year 2018 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	4,990
Year 2018 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	210,109
Year 2018 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	19,820
Year 2018 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	158,478
Year 2018 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	33,620
Year 2018 [Member] | Options [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	590
Year 2018 [Member] | Options [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	1,310
Year 2019 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	3,413
Year 2019 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	158,246
Year 2019 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	16,269
Year 2019 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	109,281
Year 2019 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	2,890
Year 2019 [Member] | Options [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	590
Year 2019 [Member] | Options [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	410
Year 2020 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	1,170
Year 2020 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	31,630
Year 2020 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	11,607
Year 2020 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	70,417
Year 2020 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	3,115
Year 2020 [Member] | Options [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2020 [Member] | Options [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2021 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	388
Year 2021 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	11,821
Year 2021 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	2,434
Year 2021 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	56,658
Year 2021 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2021 [Member] | Options [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2021 [Member] | Options [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2022 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2022 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	0
Year 2022 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2022 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	40,000
Year 2022 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2022 [Member] | Options [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2022 [Member] | Options [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2023 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2023 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	0
Year 2023 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2023 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	20,000
Year 2023 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2023 [Member] | Options [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2023 [Member] | Options [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0