Fair Value Measurements Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2013	Mar. 31, 2008
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 39
Auction frequency, min	30 days
Auction frequency, max	35 days
Available For Sale Securities Unrealized Loss	11
Auction Rate Securities, Lower Remaining Maturity Range (in years)	5 years
Auction Rate Securities, Higher Remaining Maturity Range (in years)	34 years
Auction Rate Securities at Failed Auctions		463
Auction Rate Securities Sold At Par After Failed Auctions	$ 413