Description Of Business And Basis Of Presentation Description of Business and Basis of Presentation (Impact of Recently Adopted Accounting Standards) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Mar. 31, 2014
Change in Accounting Estimate [Line Items]
Deferred Income Taxes and Other Tax Liabilities, Noncurrent	$ 96	$ 96
Deferred Income Taxes and Other Assets, Current	18	18
Deferred Tax Assets, Net, Noncurrent	11	11
Deferred Tax Liabilities, Net, Noncurrent	$ 67	$ 67
Sales Revenue, Net
Change in Accounting Estimate [Line Items]
Change in Accounting Estimate, Financial Effect	181	286	474
Diluted Earnings Per Share
Change in Accounting Estimate [Line Items]
Change in Accounting Estimate, Financial Effect	.56	.89	1.50