8. Investing Activities (Details 9) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012 Liability [Member]	Dec. 31, 2011 Liability [Member] As restated and amended [Member]	Sep. 30, 2012 Maximum Exposure of Loss [Member]	Dec. 31, 2011 Maximum Exposure of Loss [Member] As restated and amended [Member]	Sep. 30, 2012 Assets [Member]	Dec. 31, 2011 Assets [Member] As restated and amended [Member]
Debt securities, at fair value			$ 3.5	$ 0.2	$ 3.6	$ 0.3
Equity securities, at fair value			18.5	26.5	22.7	27.8
Cash and cash equivalents			9.5	3.3	9.7	3.5
Investment in partnership interests			15.4	14.6	15.4	14.6
Investment in single asset LLCs			4.1	1.0	5.0	1.7
Other assets			0.2		0.2	0.1
Total assets of consolidated VIEs			51.2	45.6	56.6	48.0
Other liabilities	0.1	0.1	0.1	0.1
Total liabilities of consolidated VIEs	$ 0.1	$ 0.1	$ 0.1	$ 0.1