Commitments And Contingent Liabilities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Loss Contingencies [Line Items]
Charges incurred	$ 44		$ 118	$ 60	$ 118
Payments Made				(438)	(6)
Average Wholesale Price Litigation [Member]
Loss Contingencies [Line Items]
AWP Litigation Reserve, Beginning Balance		453		453	330
Charges incurred	44	16	118	60	118
Payments Made	(155)			(438)	(6)
AWP Litigation Reserve, Ending Balance	$ 75		$ 442	$ 75	$ 442