Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 914	$ 955	$ 951
Other comprehensive loss:
Foreign currency translation adjustments	(16)	(47)	(43)
Total other comprehensive loss	(16)	(47)	(43)
Comprehensive income	$ 898	$ 908	$ 908