Goodwill and Intangibles Assets (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	16 years 4 months
Gross Carrying Amount	$ 1,071	$ 1,006
Accumulated Amortization	(431)	(357)
Net Carrying Amount	640	649
Impairment charges	24	4	46
Tradenames [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	20 years
Gross Carrying Amount	142	138
Accumulated Amortization	(49)	(41)
Net Carrying Amount	93	97
Technology and Software [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	12 years
Gross Carrying Amount	335	284
Accumulated Amortization	(129)	(102)
Net Carrying Amount	206	182
Impairment charges	5
Customer-related Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	20 years
Gross Carrying Amount	470	460
Accumulated Amortization	(160)	(134)
Net Carrying Amount	310	326
Favorable Energy Supply Contract [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	9 years 6 months
Gross Carrying Amount	124	124
Accumulated Amortization	(93)	(80)
Net Carrying Amount	$ 31	$ 44

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

+ Details

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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