7. Investing Activities (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011 As restated and amended [Member]	Dec. 31, 2010 As restated and amended [Member]
Balance, beginning of period	$ (21.3)	$ (19.9)	$ (15.0)
Add: Credit losses on securities not previously impaired	(1.4)	(1.0)	(1.9)
Add: Credit losses on securities previously impaired	(1.2)	(1.4)	(7.7)
Less: Credit losses on securities impaired due to intent to sell
Less: Credit losses on securities sold	6.1	1.0	1.9
Less: Credit losses upon adoption of new accounting guidance(2)			2.8
Less: Increases in cash flows expected on previously impaired securities
Balance, end of period	$ (17.8)	$ (21.3)	$ (19.9)