Income Taxes (Narrative) (Details) (USD $) In Millions	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Income Taxes [Abstract]
Unrecognized tax benefits that would impact effective tax rate	$ 126
Unrecognized tax benefits, income tax penalties and interest expense	(3)	(1)	6
Unrecognized tax benefits, income tax penalties and interest accrued	36	37
Net current deferred tax assets	400	374
Net noncurrent deferred tax liabilities	668	634
Income taxes paid	1,030	890	780
Net operating losses and tax credits	$ 242	$ 281

For entities that net deferred tax assets and tax liabilities, represents the net amount of deferred tax assets (after reduction for valuation allowance) and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities that are classified as current in the financial statements, or that are expected to reverse in the next twelve months (or normal operating cycle, if longer). A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods. In a classified statement of financial position, an enterprise separates deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets are classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, are classified according to the expected reversal date of the temporary difference.

For entities that net deferred tax assets and tax liabilities, represents the net amount of deferred tax assets (after reduction for valuation allowance) and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities that are classified as noncurrent in the financial statements, or that are expected to reverse after the next twelve months (or beyond the normal operating cycle, if longer). A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods. In a classified statement of financial position, an enterprise separates deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets are classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, are classified according to the expected reversal date of the temporary difference.

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