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Non-Recurring Fair Value Measurements (Detail) (Non-Recurring investments, USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value on a non-recurring basis of financial investments	$ 2
Private equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value on a non-recurring basis of financial investments	2
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value on a non-recurring basis of financial investments	2
Significant Unobservable Inputs (Level 3) | Private equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value on a non-recurring basis of financial investments	2
Gains (Losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value on a non-recurring basis of financial investments	(2)
Gains (Losses) | Private equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value on a non-recurring basis of financial investments	$ (2)

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- Definition

Fair Value Measured on nonrecurring basis investments.

+ References

No definition available.

+ Details

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- Details

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