Debt Obligations - Range of Interest Rates and Weighted Average Interest Rate Incurred on Variable Rate Debt Obligations (Details)	Mar. 31, 2019
TRC Revolver [Member]
Debt Instrument [Line Items]
Weighted average interest rate incurred	4.30%
TRP Revolver [Member]
Debt Instrument [Line Items]
Weighted average interest rate incurred	4.10%
Targa Resources Partners LP [Member] | Accounts Receivable Securitization Facility [Member]
Debt Instrument [Line Items]
Range of interest rates incurred	3.40%
Weighted average interest rate incurred	3.40%
Minimum [Member] | TRC Revolver [Member]
Debt Instrument [Line Items]
Range of interest rates incurred	4.20%
Minimum [Member] | TRP Revolver [Member]
Debt Instrument [Line Items]
Range of interest rates incurred	3.80%
Maximum [Member] | TRC Revolver [Member]
Debt Instrument [Line Items]
Range of interest rates incurred	4.30%
Maximum [Member] | TRP Revolver [Member]
Debt Instrument [Line Items]
Range of interest rates incurred	4.30%