Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 Swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets from commodity derivative contracts (1)	$ 3.9	[1]
Liabilities from commodity derivative contracts (1)	13.5	[1]
Badlands contingent consideration liability	0
Cash and cash equivalents	94.9
TRC Senior secured revolving credit facility	72.0
Partnership's Senior secured revolving credit facility	355.0
Partnership's Senior unsecured notes	2,284.0
Partnership's accounts receivable securitization facility	233.5
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative fair value commodity price increases 10 percent, net liability	33.1
Derivative fair value commodity price decreases 10 percent, net asset	13.8
Number of natural gas basis swaps categorized as Level 3	14
Commodity Derivative Contracts [Member]
Fair Value, Liabilities/Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, December 31, 2013	0.7
Settlements included in Revenue	(0.9)
Balance, March 31, 2014	(0.2)
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets from commodity derivative contracts (1)	0	[1]
Liabilities from commodity derivative contracts (1)	0	[1]
Badlands contingent consideration liability	0
Cash and cash equivalents	0
TRC Senior secured revolving credit facility	0
Partnership's Senior secured revolving credit facility	0
Partnership's Senior unsecured notes	0
Partnership's accounts receivable securitization facility	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets from commodity derivative contracts (1)	2.6	[1]
Liabilities from commodity derivative contracts (1)	12.0	[1]
Badlands contingent consideration liability	0
Cash and cash equivalents	0
TRC Senior secured revolving credit facility	72.0
Partnership's Senior secured revolving credit facility	355.0
Partnership's Senior unsecured notes	2,284.0
Partnership's accounts receivable securitization facility	233.5
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets from commodity derivative contracts (1)	1.3	[1]
Liabilities from commodity derivative contracts (1)	1.5	[1]
Badlands contingent consideration liability	0
Cash and cash equivalents	0
TRC Senior secured revolving credit facility	0
Partnership's Senior secured revolving credit facility	0
Partnership's Senior unsecured notes	0
Partnership's accounts receivable securitization facility	0
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets from commodity derivative contracts (1)	3.9	[1]
Liabilities from commodity derivative contracts (1)	13.5	[1]
Badlands contingent consideration liability	0
Cash and cash equivalents	94.9
TRC Senior secured revolving credit facility	72.0
Partnership's Senior secured revolving credit facility	355.0
Partnership's Senior unsecured notes	2,231.2
Partnership's accounts receivable securitization facility	$ 233.5

[1] The fair value of the derivative contracts in this table is presented on a different basis than the balance sheet presentation as disclosed in Note 13. The above fair values reflect the total value of each derivative contract taken as a whole, whereas the balance sheet presentation is based on the individual maturity dates of estimated future settlements. As such, an individual contract could have both an asset and liability position when segregated into its current and long-term portions for balance sheet classification purposes.