Share-Based Compensation (Details 4) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Mar. 31, 2012 Y
Range of Exercise Prices - Range 1 [Member]
Outstanding Options
Exercise price - lower limit	$ 0.00
Exercise price - upper limit	$ 17.40
Outstanding Options, Shares	0.9
Outstanding Options, Weighted-Average Exercise Price	$ 16
Outstanding Options, Weighted-Average Remaining Contractual Life	2
Exercisable Options, Shares	0.9
Exercisable Options, Weighted-Average Exercise Price	$ 16
Range of Exercise Prices - Range 2 [Member]
Outstanding Options
Exercise price - lower limit	$ 17.41
Exercise price - upper limit	$ 19.93
Outstanding Options, Shares	0.5
Outstanding Options, Weighted-Average Exercise Price	$ 19
Outstanding Options, Weighted-Average Remaining Contractual Life	3
Exercisable Options, Shares	0.5
Exercisable Options, Weighted-Average Exercise Price	$ 19
Range of Exercise Prices - Range 3 [Member]
Outstanding Options
Exercise price - lower limit	$ 19.94
Exercise price - upper limit	$ 25.41
Outstanding Options, Shares	0.2
Outstanding Options, Weighted-Average Exercise Price	$ 22
Outstanding Options, Weighted-Average Remaining Contractual Life	2
Exercisable Options, Shares	0.2
Exercisable Options, Weighted-Average Exercise Price	$ 22
Range of Exercise Prices - Range 4 [Member]
Outstanding Options
Exercise price - lower limit	$ 25.42
Exercise price - upper limit	$ 31.69
Outstanding Options, Shares	0.5
Outstanding Options, Weighted-Average Exercise Price	$ 28
Outstanding Options, Weighted-Average Remaining Contractual Life	4
Exercisable Options, Shares	0.4
Exercisable Options, Weighted-Average Exercise Price	$ 28
Range of Exercise Prices - Range 5 [Member]
Outstanding Options
Exercise price - lower limit	$ 31.70
Exercise price - upper limit	$ 32.15
Outstanding Options, Shares	1.1
Outstanding Options, Weighted-Average Exercise Price	$ 32
Outstanding Options, Weighted-Average Remaining Contractual Life	1
Exercisable Options, Shares	1.1
Exercisable Options, Weighted-Average Exercise Price	$ 32
Range of Exercise Prices - Range 6 [Member]
Outstanding Options
Exercise price - lower limit	$ 32.16
Exercise price - upper limit	$ 36.84
Outstanding Options, Shares	0.4
Outstanding Options, Weighted-Average Exercise Price	$ 36
Outstanding Options, Weighted-Average Remaining Contractual Life	2
Exercisable Options, Shares	0.4
Exercisable Options, Weighted-Average Exercise Price	$ 36
Range of Exercise Prices - Range 7 [Member]
Outstanding Options
Exercise price - lower limit	$ 36.85
Exercise price - upper limit	$ 39.30
Outstanding Options, Shares	1.9
Outstanding Options, Weighted-Average Exercise Price	$ 39
Outstanding Options, Weighted-Average Remaining Contractual Life	2
Exercisable Options, Shares	1.8
Exercisable Options, Weighted-Average Exercise Price	$ 39

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-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 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

-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 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, 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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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- Definition

The weighted-average period remaining as of the balance sheet date until option expiration pertaining to the outstanding stock options for all option plans in the customized range of exercise prices, which may be expressed in a variety of ways (for example, years, months).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

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