Income Tax Provision (Narratives) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Operating Loss Carryforwards [Line Items]
Income Taxes Receivable	$ 13	$ 23
Deferred Tax Assets, Tax Credit Carryforwards, Federal and State	58	50
Valuation Allowance	16	4
Net Taxes Paid	21	(112)	35
Net Income Tax Refunds		112
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	1	2	2
Interest on Income Taxes Accrued, Maximum	1	1	1
Income Tax Examination Refund		105
Unremitted earnings in foreign subsidiary	171
Federal [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	552	1,043
Expiration Dates	fiscal 2029 through fiscal 2031 fiscal 2029 through fiscal 2032
State [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	55	61
Expiration Dates	fiscal 2014 through fiscal 2032 fiscal 2013 through fiscal 2031
Income Taxes Receivable	$ 7	$ 6