Goodwill And Intangible Assets, Net (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Goodwill And Intangible Assets, Net [Abstract]
Amortization expense of intangible assets	$ 191	$ 132	$ 121
Annual amortization expense, 2013	200
Annual amortization expense, 2014	186
Annual amortization expense, 2015	166
Annual amortization expense, 2016	142
Annual amortization expense, 2017	122
Annual amortization expense, after 2017	$ 934