Income Taxes (Components Of Provision For Income Taxes Related To Continuing Operations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Income Tax Disclosure [Abstract]
Federal	$ (85)	$ 271	$ 283
State and local	14	52	40
Foreign	46	28	54
Total current	(25)	351	377
Federal	542	129	121
State and local	80	29	1
Foreign	(16)	7	6
Total deferred	606	165	128
Income tax provision	$ 581	$ 516	$ 505