Airgas Transaction (Details) (USD $) Share data in Millions, except Per Share data	0 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended				0 Months Ended
	Feb. 16, 2011	Feb. 03, 2011	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Sep. 30, 2010	Dec. 31, 2010	Dec. 09, 2010	Feb. 28, 2010	Feb. 03, 2011 Amended Credit Facility [Member]
Cash price per share of tender offer to purchase outstanding common stock of Airgas, Inc., including the associated preferred stock purchase rights									$ 70.00	$ 60.00
Total value of transaction									$ 7,800,000,000
Equity component of transaction									6,100,000,000
Debt component of transaction									1,700,000,000
Credit facility								6,700,000,000			6,700,000,000
Line of credit facility, expiration date											4 June 2011
Underwriting fees incurred		0
Early termination penalties incurred	0
Number of shares purchased prior to tender offer							1.5
Airgas stock purchased prior to tender offer						69,600,000	69,600,000
Number of shares sold prior to tender offer	1.5
Proceeds from sale of Airgas stock	94,700,000				94,700,000
Recognized gain on sale of stock	25,100,000
Recognized gain on sale of stock, after tax	15,900,000
Recognized gain on sale of stock, per share	$ 0.07
Transaction costs incurred during period							96,000,000
Payment of acquisition related costs					156,200,000	8,800,000
Net loss on Airgas transaction				37,900,000	48,500,000	61,300,000
Transaction costs incurred during period, after tax					31,600,000
Transaction costs incurred during period, after tax							$ 60,100,000
Transaction costs incurred during period, after tax, per share					$ 0.14
Transaction costs incurred during period, after tax, per share							$ 0.28