Business Segments - Extinguishment of Debt (Details) $ in Millions	3 Months Ended
Dec. 31, 2010 USD ($)
Debt Instrument [Line Items]
Extinguishment of debt	$ 1,800
Senior Notes [Member]
Debt Instrument [Line Items]
Subordinated debt	$ 1,900

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration