Stock-Based Compensation (Narrative)(Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for stock option and incentive shares plans	$ 100	$ 121	$ 217
Income tax benefits recognized in income statement for compensation arrangements	28	32	65
Unrecognized compensation cost related to non-vested awards granted	122
Unrecognized compensation cost is expected to be recognized, weighted-average period, years	1 year 7 months
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options granted at the closing market price of common stock on the grant date	100.00%
Percentage of options granted at average of high and low prices of common stock on date of grant		100.00%
Amount of stock option vesting per year	one-third
Stock option expiration years from date of grant years	10 years
Share-based compensation arrangement by share-based payment award, number of shares available for grant	19,700,000
Weighted-average price of shares granted	$ 7.53	$ 11.00	$ 8.51
Cash received for stock options exercises	42	65	53
Options exercised, total intrinsic value	38	49	59
Actual tax benefit realized from tax deductions related to option exercises	11	16	4
Risk-free interest rate	1.30%	1.90%	3.00%
Expected dividend yield	3.70%	2.60%	3.20%
Expected volatility rate	27.00%	25.00%	25.00%
Expected life of option	7 years	7 years	7 years
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period		4,777,248
Common shares issued		2,841,534
Shares withheld for income tax		1,661,045
Paid in cash for share-based compensation		274,669
Award rights to receive common shares	5,273,566	5,367,146
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period	345,946
Common shares issued	209,168
Shares withheld for income tax	136,778
Unvested shares outstanding	1,525,000
Restricted Stock [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, minimum, in years	3 years
Restricted Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, minimum, in years	10 years
Incentive Shares Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	10,000,000
Shares vested in period	346,000
Unvested shares outstanding	6,799,000	7,101,000
Total fair value of shares vested	15	276	42
Cash paid primarily for tax withholdings	$ 6	$ 113	$ 15
Restricted Stock For Non Management Directors Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	290,813
Restricted stock awarded	22,921
Restricted stock units awarded	4,818

Amount Of Stock Option Vesting Per Year

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Employee service share-based compensation, cash paid primarily to taxing authorities from exercise of incentive shares

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Paid in cash for share-based compensation.

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Percentage of options granted at average of high and low prices of common stock on date of grant.

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No definition available.

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Percentage of options granted at the closing market price of common stock on the grant dat

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Restricted stock awarded

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Restricted stock units awarded.

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Share based compensation arrangement by share based payment award rights to receive common shares .

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Stock option expiration years from date of grants.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph 1

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Aggregate proceeds received by the entity during the annual period from exercises of stock or unit options and conversion of similar instruments granted under equity-based payment arrangements.

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As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The total fair value of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section D

-Subsection 2

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Number of share instruments newly issued under a share-based compensation plan.

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

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No definition available.

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