Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Commodity Derivative Contracts [Member]	Mar. 31, 2013 Contingent Liability[Member]	Mar. 31, 2013 Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member]	Mar. 31, 2013 Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member]	Mar. 31, 2013 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member]	Mar. 31, 2013 Carrying (Reported) Amount, Fair Value Disclosure [Member]	Dec. 31, 2012 Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets from commodity derivative contracts	$ 21.4	$ 34.3			$ 0	$ 0	$ 21.4	$ 34.3	$ 0	$ 0	$ 21.4	$ 34.3
Liability from commodity derivative contracts	13.2	12.1			0	0	12.2	11.5	1.0	0.6	13.2	12.1
Badlands contingent consideration liability (see Note 4)	15.6	15.3			0	0	0	0	15.6	15.3	15.6	15.3
Cash and cash equivalents	112.7	76.3									112.7	76.3
TRC Senior secured revolving credit facility	72.0	82.0			0	0	72.0	82.0	0	0	72.0	82.0
Partnership's Senior secured revolving credit facility	565.0	620.0			0	0	565.0	620.0	0	0	565.0	620.0
Partnership's Senior unsecured notes	1,949.8	1,945.2			0	0	1,949.8	1,945.2	0	0	1,774.0	1,773.3
Partnership's accounts receivable securitization facility	111.4				0		111.4		0		111.4
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments, fair value, net	8.2
Derivative fair value commodity price increases 10 percent, net asset	18.7
Derivative fair value commodity price decreases 10 percent, net asset	35.1
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period			0.6	15.3
Loss included in Revenue			0.4	0
Loss included in Other expense			0	0.3
Balance at end of period			$ 1.0	$ 15.6