Derivative Financial Instruments Gross Notional Amounts and Fair Values for Currency Derivatives (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Mar. 31, 2014
Foreign currency contracts to purchase | Foreign exchange forward contracts
Derivative
Fair value of foreign currency contracts outstanding, Assets	$ 0	$ 0
Fair value of foreign currency contracts outstanding, Liabilities	5	3
Foreign currency contracts to purchase | Designated as Hedging Instrument [Member] | Foreign exchange forward contracts
Derivative
Derivative, Notional amount	121	179
Foreign currency contracts to sell | Foreign exchange forward contracts
Derivative
Fair value of foreign currency contracts outstanding, Assets	11	0
Fair value of foreign currency contracts outstanding, Liabilities	0	2
Foreign currency contracts to sell | Designated as Hedging Instrument [Member] | Foreign exchange forward contracts
Derivative
Derivative, Notional amount	246	363
Foreign currency contracts to purchase | United States Dollar [Member] | Not Designated as Hedging Instrument [Member]
Derivative
Derivative, Notional amount	77	140
Foreign currency contracts to purchase | Balance Sheet Hedging [Member] | Not Designated as Hedging Instrument [Member]
Derivative
Derivative Asset, Current	0	0
Derivative Liability, Current	1	1
Foreign currency contracts to sell | United States Dollar [Member] | Not Designated as Hedging Instrument [Member]
Derivative
Derivative, Notional amount	444	232
Foreign currency contracts to sell | Balance Sheet Hedging [Member] | Not Designated as Hedging Instrument [Member]
Derivative
Derivative Asset, Current	1	0
Derivative Liability, Current	$ 0	$ 0