Short-Term Financing (Details) (USD $)	12 Months Ended	1 Months Ended	12 Months Ended
	Jun. 30, 2011	Aug. 31, 2011 Issuance Of Debt [Member]	Jun. 30, 2011 Issuance Of Debt [Member]	Jun. 30, 2011 Short-Term Commercial Paper Program [Member]	Jun. 30, 2010 Short-Term Commercial Paper Program [Member]	Jun. 30, 2011 Three Hundred And Sixty Four Day Credit Facility [Member]	Jun. 30, 2010 Three Hundred And Sixty Four Day Credit Facility [Member]	Jun. 30, 2011 Credit Facility Expiring In June 2015 [Member]	Jun. 30, 2011 Credit Facility Expiring In June 2011 [Member]	Jun. 30, 2011 Credit Facility Expiring In June 2013 [Member]	Jun. 30, 2011 Reverse Repurchase Agreements [Member]	Jun. 30, 2010 Reverse Repurchase Agreements [Member]
Maximum borrowing capacity under credit facilities						$ 2,000,000,000	$ 2,500,000,000	$ 3,250,000,000	$ 2,250,000,000	$ 1,500,000,000	$ 2,000,000,000
Expiration date of credit facilities								June 2015	June 2011	June 2013
Additional borrowing capacity under credit facilities								500,000,000	500,000,000
Aggregate amount of commercial paper issuable under the short-term commercial paper program		6,750,000,000	6,250,000,000
Average outstanding borrowings				1,600,000,000	1,600,000,000						505,200,000	425,000,000
Weighted average interest rate				0.20%	0.20%						0.40%	0.20%
Outstanding borrowings				$ 0	$ 0						$ 0	$ 0
Weighted average maturity of borrowings under the short-term commercial paper program				less than two days	less than two days
Maturities of commercial paper range	overnight to up to 364 days