Consolidated Statement of Shareholder's Equity (Parenthetical) (Accumulated Other Comprehensive Income (Loss) (AOCI), USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) (AOCI)
Tax on currency translation adjustment	$ 0	$ 0	$ 0
Tax on change in fair value of cash flow hedges	1	(3)	0
Tax on change in pension and other benefits	$ 71	$ 47	$ 15