Derivative Financial Instruments Gross Notional Amounts and Fair Values for Currency Derivatives (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013
Derivative
Fair value of foreign currency contracts outstanding	$ 5	$ 6
Foreign Exchange Option [Member]
Derivative
Fair value of foreign currency contracts outstanding	5	6
Designated as Hedging Instrument [Member]
Derivative
Notional value of foreign currency purchase contracts	48	84
Notional value of foreign currency sale contracts	231	149
Designated as Hedging Instrument [Member] | Foreign Exchange Option [Member]
Derivative
Notional value of foreign currency purchase contracts	40	84
Notional value of foreign currency sale contracts	184	149
Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Derivative
Notional value of foreign currency purchase contracts	8
Notional value of foreign currency sale contracts	$ 47