Equity and Noncontrolling Interests - Changes in Redeemable Noncontrolling Interests (Detail) (USD $) In Millions, unless otherwise specified				3 Months Ended	6 Months Ended
Mar. 31, 2013	Sep. 30, 2012	Mar. 31, 2012	Mar. 31, 2013 Redeemable Noncontrolling Interests	Mar. 31, 2012 Redeemable Noncontrolling Interests	Mar. 31, 2013 Redeemable Noncontrolling Interests	Mar. 31, 2012 Redeemable Noncontrolling Interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance	$ 205	$ 253	$ 318	$ 270	$ 282	$ 253	$ 260
Net income				13	25	32	45
Foreign currency translation adjustments				0	1
Dividends				(6)	(1)	(6)	(9)
Redemption value adjustment				(61)	(6)	(63)	(1)
Change in noncontrolling interest share				(11)	17	(11)	23
Ending balance	$ 205	$ 253	$ 318	$ 205	$ 318	$ 205	$ 318

- Definition

The aggregate amount to be paid by the entity upon redemption of the security that is classified as temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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