Assets and Liabilities, at Fair Value Assets and Liabilities, at Fair Value - Available for Sale Securities - Fin Inst (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	$ 660.5	$ 1,305.7
Available-for-sale Securities, Gross Unrealized Gains	0.1	0.1
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Debt Securities	$ 660.6	$ 1,305.8

Amount of debt securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details