Derivative Instruments and Hedging Activities - Notional Volumes Of The Partnership's Commodity Derivative Contracts (Details) - Targa Resources Partners LP [Member]	3 Months Ended
	Mar. 31, 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	170,739
Year 2018 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	22,779
Year 2018 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	138,009
Year 2018 [Member] | OptionMember | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	590
Year 2018 [Member] | OptionMember | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	5,096
Year 2018 [Member] | OptionMember | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	1,310
Year 2018 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	8,923
Year 2019 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	2,653
Year 2019 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	131,506
Year 2019 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	13,449
Year 2019 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	78,062
Year 2019 [Member] | OptionMember | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	590
Year 2019 [Member] | OptionMember | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	0
Year 2019 [Member] | OptionMember | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	410
Year 2019 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	1,383
Year 2020 [Member] | Swaps [Member] | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2020 [Member] | Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	0
Year 2020 [Member] | Swaps [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	4,567
Year 2020 [Member] | Basis Swaps [Member] | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	10,417
Year 2020 [Member] | OptionMember | Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2020 [Member] | OptionMember | Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in MMBtu per day) | MMBTU	0
Year 2020 [Member] | OptionMember | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0
Year 2020 [Member] | Future [Member] | NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (in Bbl per day)	0