Stock-Based Compensation (Details Textuals) (USD $)	12 Months Ended
Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2009
Stock Based Compensation (Textuals) [Abstract]
The total intrinsic value of options and SSARs Rights exercised	$ 25,000,000	$ 18,000,000	$ 17,000,000
Period after which stock options and SSARs granted under the Plan become exercisable	3 years
Vesting Period for Which Stock options and SSARs granted under the Plan become expire after Grant date	7 years
Grant-date fair value per award	12.66	9.42	11.24
Special Cash Dividend Per Share On Class A and Class B Common Stock		$ 1
Stock-based incentive awards on a pre-tax	9,000,000	8,000,000	7,000,000
Compensation expense partially offset by deferred income tax benefits	4,000,000	3,000,000	3,000,000
Total unrecognized compensation cost related to non-vested stock-based compensation	9,000,000
Cost recognized over weighted-average period (in years)	2.0
Omnibus Compensation Plan 2004 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under 2004 Omnibus Compensation Plan	7,433,000
Shares issued under 2004 Omnibus Compensation Plan	4,265,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding under Restricted stock units	82,000	176,000
Weighted-average remaining restriction period (in years)	1.8
Total fair value of Restricted stock units and restricted stock vested	$ 9,000,000	$ 2,000,000	$ 3,000,000

Share based compensation arrangement by award options and stock settled appreciation rights award expiration period.

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- Definition

Share based compensation arrangement by award options and stock settled appreciation rights award vesting period.

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- Definition

Share Based Compensation Arrangement By Award Options And Stock Settled Appreciation Rights Exercises In Period Intrinsic Value.

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- Definition

Share Based Compensation Arrangement By AwardOptions And Stock Settled Appreciation Rights Grants In Period Weighted Average Grant Date Fair Value.

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- Definition

Share Based Compensation Arrangement By Other Than Options weighted average remaining restriction period.

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- Definition

Special Cash Dividend.

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- Definition

Stock Based Compensation.

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- Definition

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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- Definition

The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years.

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- Definition

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

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- Definition

The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28
-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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(2)(a)
-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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(2)(b)
-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.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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

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.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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