Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended				12 Months Ended				12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2013 Permanently Invested Foreign Earnings [Member]	Mar. 31, 2013 Internal Revenue Service (IRS) [Member]	Mar. 31, 2013 Foreign Country [Member]	Mar. 31, 2013 State [Member]	Mar. 31, 2012 State [Member]	Jan. 19, 2012 Canada Revenue Agency [Member]
Income Tax Disclosure [Line Items]
Undistributed earnings of foreign subsidiaries				$ 1,381
Valuation allowance decrease	23
Net operating loss ("NOL") carry forwards					588		799
Net operating loss attributable to various acquired companies					221			137
Operating loss carryforwards, expiration dates					2029		2016
Tax credit carry forwards					119	26	113
Tax credit carryforward, expiration dates						Jan. 01, 2017
Gross unrecognized tax benefits	297	274	273
Cash deposits to offset uncertain tax liabilities	46	43
Unrecognized tax benefits, income tax penalties and interest expense	2
Amount of unrecognized tax benefits that would affect the effective tax rate	106	98
The total amount of unrecognized tax benefits that, if recognized, would result in adjustments to deferred tax assets with corresponding	177	163
Combined amount of accrued interest and penalties related to uncertain tax positions	23	21
Amount of unrecognized tax benefits for which it is reasonably possible that there will be a reduction within the next 12 months	80
Incremental tax liability asserted by jurisdiction									$ 44