Amount borrowed under the credit facility as of the balance sheet date.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects when the credit facility terminates, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects when the credit facility first became available, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Liquidity Facilities and Letters of Credit (Details) (USD $) In Billions, unless otherwise specified	3 Months Ended	12 Months Ended					1 Months Ended			1 Months Ended			1 Months Ended			1 Months Ended			12 Months Ended			12 Months Ended
	Sep. 30, 2012	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2012	Feb. 29, 2012 364 Day Credit Agreement [Member]	Sep. 30, 2012 364 Day Credit Agreement [Member]	Mar. 31, 2012 364 Day Credit Agreement [Member]	Mar. 31, 2011 Three Year Agreement [Member]	Sep. 30, 2012 Three Year Agreement [Member]	Mar. 31, 2012 Three Year Agreement [Member]	Mar. 31, 2011 Five Year Agreement [Member]	Sep. 30, 2012 Five Year Agreement [Member]	Mar. 31, 2012 Five Year Agreement [Member]	Jan. 31, 2012 Committed Revolving Asset-backed Commercial Paper Facility [Member]	Sep. 30, 2012 Committed Revolving Asset-backed Commercial Paper Facility [Member]	Mar. 31, 2012 Committed Revolving Asset-backed Commercial Paper Facility [Member]	Mar. 31, 2013 Other Credit Agreements [Member] 2013 [Member] Committed Bank Credit [Member]	Sep. 30, 2012 Other Credit Agreements [Member] 2013 [Member] Committed Bank Credit [Member]	Mar. 31, 2012 Other Credit Agreements [Member] 2013 [Member] Committed Bank Credit [Member]	Mar. 31, 2014 Other Credit Agreements [Member] 2013 [Member] Uncommitted Bank Credit [Member]	Mar. 31, 2014 Other Credit Agreements [Member] 2014 [Member] Committed Bank Credit [Member]	Sep. 30, 2012 Other Credit Agreements [Member] 2014 [Member] Committed Bank Credit [Member]	Mar. 31, 2012 Other Credit Agreements [Member] 2014 [Member] Committed Bank Credit [Member]	Sep. 30, 2012 Other Credit Agreements [Member] 2014 [Member] Uncommitted Bank Credit [Member]	Mar. 31, 2012 Other Credit Agreements [Member] 2014 [Member] Uncommitted Bank Credit [Member]	Sep. 30, 2012 Other Credit Agreements [Member] 2015 [Member] Committed Bank Credit [Member]
Line of Credit Facility [Line Items]
Initiation Date							February 2012			March 2011			March 2011			January 2012
Maximum Borrowing Capacity							$ 5.0			$ 5.0		$ 4.3	$ 3.0		$ 2.6	$ 3.0				$ 0.7				$ 1.2		$ 0.5		$ 0.5
Expiration Date	FY2013	FY2017	FY2016	FY2015 FY2015	FY2014														FY2013			FY2014	FY2014
Credit facilities amount outstanding	$ 0					$ 0		$ 0	$ 0		$ 0	$ 0		$ 0	$ 0		$ 2.1	$ 2.4		$ 0	$ 0			$ 0	$ 0	$ 0	$ 0