Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Schedule of Segment's Revenue [Table Text Block]

Below are the third-party customers that accounted for more than 10% of our segment’s revenues:

	2014		2013		2012
Oil and Natural Gas:
Valero Energy Corporation	24	%	25	%	26	%
Sunoco Partners Marketing	14	%	8	%	8	%
Drilling:
QEP Resources, Inc.	19	%	18	%	15	%
Whiting Petroleum Corp. (formerly Kodiak Oil and Gas Corp.)	9	%	10	%	10	%
Mid-Stream:
ONEOK Partners, L.P.	44	%	57	%	54	%
Tenaska Resources, LLC	22	%	16	%	7	%
Laclede Gas Company	10	%	2	%	—	%
Gavilon, LLC	—	%	—	%	10	%

Schedule Of Fair Values Of The Net Assets (Liabilities) [Table Text Block]

At December 31, 2014, the fair values of the net assets (liabilities) we had with each of the counterparties with respect to all of our commodity derivative transactions are listed in the table below:

	December 31, 2014
	(In millions)
Bank of Montreal	$	27.8
Scotiabank	3.3
Total assets	$	31.1