Short-Term Financing (Details) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Short-term Debt [Line Items]
Long-term Line of Credit	$ 0		$ 0
Commercial Paper	0		$ 0		$ 0
Maturities of commercial paper range			overnight to up to 364 days
Commercial Paper Weight Average Maturity			2 days
Maturities of short-term funding agreements			overnight to up to five business days
Obligations under reverse repurchase agreements	$ 0		$ 0		$ 0
Short Term Commercial Paper Program [Member]
Short-term Debt [Line Items]
Commercial Paper Weight Average Maturity	2 days		2 days
364-Day Credit Agreement [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	$ 2,750,000,000		$ 2,750,000,000
Term of credit			364 days
Expiration date of credit facilities			Jun. 16, 2016
Credit Facility Expiring In June Two Thousand Nineteen [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	3,250,000,000		$ 3,250,000,000
Term of credit			5 years
Expiration date of credit facilities			Jun. 18, 2019
Line of credit facility potentially available increase in maximum borrowing capacity			$ 500,000,000
Credit Facility Expiring In June Two Thousand Twenty [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	2,250,000,000		$ 2,250,000,000
Term of credit			5 years
Expiration date of credit facilities			Jun. 17, 2020
Line of credit facility potentially available increase in maximum borrowing capacity			$ 500,000,000
Commercial Paper [Member]
Short-term Debt [Line Items]
Aggregate amount of commercial paper issuable under the short-term commercial paper program	8,250,000,000.0
Short-term Debt, Average Outstanding Amount	$ 3,300,000,000	$ 3,000,000,000	$ 3,400,000,000	$ 3,100,000,000
Debt Instrument, Interest Rate During Period	0.20%	0.10%	0.20%	0.10%
Reverse Repurchase Agreements [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	$ 3,250,000,000		$ 3,250,000,000
Short-term Debt, Average Outstanding Amount	$ 334,900,000	$ 598,600,000	$ 410,200,000	$ 584,700,000
Debt Instrument, Interest Rate During Period	0.30%	0.50%	0.40%	0.50%