Investments Equity Securities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Equity securities - adjusted cost	$ 341.4	$ 341.9
Available-for-sale Securities, Equity Securities	627.7	580.8
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity securities, OTTI adjustments	138.5	138.5
Equity securities - adjusted cost	341.4	341.9
Equity securities, gross unrealized gains	286.2	243.5
Equity securities, gross unrealized losses	0	4.6
Available-for-sale Securities, Equity Securities	$ 627.7	$ 580.8

For an unclassified balance sheet, this item represents equity securities categorized neither as held-to-maturity nor trading.

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