Property, Plant and Equipment and Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 4,919.6	$ 4,708.0
Accumulated depreciation	(1,227.2)	(1,170.0)
Property, plant and equipment, net	3,692.4	3,538.0
Estimated amortization expense for intangible assets [Abstract]
2013	27.1
2014	61.4
2015	80.1
2016	88.3
2017	81.5
Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives (in years)	20
Natural Gas Gathering Systems [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum (in years)	5
Estimated useful life, maximum (in years)	20
Processing and Fractionation Facilities [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum (in years)	5
Estimated useful life, maximum (in years)	25
Terminaling and Storage Facilities [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum (in years)	5
Estimated useful life, maximum (in years)	25
Transportation Assets [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum (in years)	10
Estimated useful life, maximum (in years)	25
Other Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum (in years)	3
Estimated useful life, maximum (in years)	25
Targa Resources Partners LP [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	4,912.8	4,701.2
Accumulated depreciation	(1,225.1)	(1,168.0)
Property, plant and equipment, net	3,687.7	3,533.2
Intangible assets	680.8	680.8
Accumulated amortization	(6.7)	0
Intangible assets, net	674.1	680.8
Targa Resources Partners LP [Member] | Natural Gas Gathering Systems [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	2,048.0	1,975.3
Targa Resources Partners LP [Member] | Processing and Fractionation Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	1,262.1	1,251.6
Targa Resources Partners LP [Member] | Terminaling and Storage Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	502.6	462.0
Targa Resources Partners LP [Member] | Transportation Assets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	292.6	292.5
Targa Resources Partners LP [Member] | Other Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	86.7	84.6
Targa Resources Partners LP [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	87.1	87.1
Targa Resources Partners LP [Member] | Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	633.7	548.1
Parent Company excluding Partnership [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	4,919.6	4,708.0
Accumulated depreciation	(1,227.2)	(1,170.0)
Property, plant and equipment, net	3,692.4	3,538.0
Intangible assets	680.8	680.8
Accumulated amortization	(6.7)	0
Intangible assets, net	674.1	680.8
Parent Company excluding Partnership [Member] | Natural Gas Gathering Systems [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	2,048.0	1,975.3
Parent Company excluding Partnership [Member] | Processing and Fractionation Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	1,268.7	1,258.2
Parent Company excluding Partnership [Member] | Terminaling and Storage Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	502.6	462.0
Parent Company excluding Partnership [Member] | Transportation Assets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	292.6	292.5
Parent Company excluding Partnership [Member] | Other Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	86.9	84.8
Parent Company excluding Partnership [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	87.1	87.1
Parent Company excluding Partnership [Member] | Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	633.7	548.1
TRC Non Partnership [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	6.8	6.8
Accumulated depreciation	(2.1)	(2.0)
Property, plant and equipment, net	4.7	4.8
Intangible assets	0	0
Accumulated amortization	0	0
Intangible assets, net	0	0
TRC Non Partnership [Member] | Natural Gas Gathering Systems [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	0	0
TRC Non Partnership [Member] | Processing and Fractionation Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	6.6	6.6
TRC Non Partnership [Member] | Terminaling and Storage Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	0	0
TRC Non Partnership [Member] | Transportation Assets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	0	0
TRC Non Partnership [Member] | Other Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	0.2	0.2
TRC Non Partnership [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	0	0
TRC Non Partnership [Member] | Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 0	$ 0