Equity and Distributions, Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Abstract]
Commodity derivative instruments	$ 10.1	[1]	$ (21.4)	[1]
Interest rate derivative instruments	(383)	[1]	(329)	[1]
Foreign currency translation adjustment	1.7	[2]	1.7	[2]
Pension and postretirement benefit plans	0.8		(1.7)
Other	0		(1)
Total	$ (370.4)		$ (351.4)

[1] See Note 6 for additional information regarding our derivative instruments.

[2] Relates to transactions of a Canadian subsidiary.