Stock Plans 7 (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Restricted Stock Units [Member]
Summarizes Activity of RSA's and RSU's Under Plans
Beginning Balance, Shares	1.0	0.9	0.6
Weighted Average Grant Date Fair Value, Beginning of Period	$ 20.03	$ 20.51	$ 24.99
Shares of RSAs and RSUs granted	0.7	0.6	0.6
RSAs/RSUs granted, Weighted Average Grant Date Fair Value	$ 24.06	$ 21.30	$ 17.52
RSAs/RSUs released	(0.3)	(0.4)	(0.2)
RSAs/RSUs released, Weighted Average Grant Date Fair Value	$ 20.70	$ 23.47	$ 23.13
RSAs/RSUs forfeitures	(0.2)	(0.1)	(0.1)
RSAs/RSUs forfeitures, Weighted Average Grant Date Fair Value	$ 21.61	$ 19.05	$ 20.95
Ending Balance, Shares	1.2	1.0	0.9
Weighted Average Grant Date Fair Value, End of Period	$ 21.91	$ 20.03	$ 20.51
Restricted Stock Awards [Member]
Summarizes Activity of RSA's and RSU's Under Plans
Beginning Balance, Shares	5.8	5.3	4.6
Weighted Average Grant Date Fair Value, Beginning of Period	$ 20.56	$ 20.73	$ 24.73
Shares of RSAs and RSUs granted	3.8	4.7	4.3
RSAs/RSUs granted, Weighted Average Grant Date Fair Value	$ 24.54	$ 21.41	$ 18.45
RSAs/RSUs released	(3.0)	(3.3)	(3.3)
RSAs/RSUs released, Weighted Average Grant Date Fair Value	$ 21.57	$ 22.00	$ 23.11
RSAs/RSUs forfeitures	(0.9)	(0.9)	(0.3)
RSAs/RSUs forfeitures, Weighted Average Grant Date Fair Value	$ 22.33	$ 20.72	$ 22.23
Ending Balance, Shares	5.7	5.8	5.3
Weighted Average Grant Date Fair Value, End of Period	$ 22.41	$ 20.56	$ 20.73