Commitments and Contingent Liabilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Loss Contingencies [Line Items]
Loss contingency	$ 0	$ 18	$ 0	$ 68
Average Wholesale Price Litigation [Member]
Loss Contingencies [Line Items]
Litigation reserve	5		5		5
Distribution Solutions [Member] | Average Wholesale Price Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency	$ 0	$ 18	$ 0	$ 68