Stock Plans 2 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2014
Unrecognized share-based compensation costs
Unrecognized share-based compensation costs	$ 92
Weighted average period expected to be recognized (in years)	1 year 10 months 24 days
Stock Option Awards [Member]
Unrecognized share-based compensation costs
Unrecognized share-based compensation costs	8
Weighted average period expected to be recognized (in years)	2 years 0 months 0 days
Restricted Stock Units [Member]
Unrecognized share-based compensation costs
Unrecognized share-based compensation costs	17
Weighted average period expected to be recognized (in years)	1 year 10 months 24 days
Restricted Stock Awards [Member]
Unrecognized share-based compensation costs
Unrecognized share-based compensation costs	51
Weighted average period expected to be recognized (in years)	1 year 9 months 18 days
Performance Share Units [Member]
Unrecognized share-based compensation costs
Unrecognized share-based compensation costs	$ 16
Weighted average period expected to be recognized (in years)	2 years 3 months 18 days