General Accounting Matters (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Income Tax Expense (Benefit) [Abstract]
Benefit from (provision for) income taxes	$ (2.4)		$ (11.6)		$ 23.5		$ (26.1)
Income tax benefit from the conversion of company structure					46.5
Other Nonoperating Income (Expense) [Abstract]
Gain on sales of available-for-sale equity securities of Energy Transfer Equity	0	[1]	0	[1]	68.8	[1]	0	[1]
Distribution income from Energy Transfer Equity	0		0		4.1		0
Other	1.2		(1.3)		(0.2)		(1.1)
Total	$ 1.2		$ (1.3)		$ 72.7		$ (1.1)

[1] See Note 7 for information regarding the liquidation of our investment in limited partnership units of Energy Transfer Equity.