Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, income tax expense (benefit) of $22, ($2), $24 and $2	$ 22	$ (2)	$ 24	$ 2
Unrealized gains (losses) on cash flow hedges, income tax expense of nil, nil, nil and nil	0	0	0	0
Retirement-related benefit plans, income tax expense of $3, $2, $7 and $5	$ 3	$ 2	$ 7	$ 5