Capital Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Jan. 11, 2013 SLFI	Jul. 11, 2012 SLFI	Jan. 10, 2012 SLFI
Capital Stock
Number of classes of authorized capital stock	2
Par value and shares authorized
Special shares authorized	25,000,000
Par Value (in dollars per share)	$ 0.50
Shares Authorized	25,000,000
Shares issued and outstanding
Common shares, shares issued	10,160,016	10,160,014	1	1	1
Common shares, shares outstanding	10,160,016	10,160,014
Capital contributions received to satisfy hybrid debt semi-annual interest payments			$ 10.5	$ 10.5	$ 10.5