Hedging Activities - Narrative (Details) - Foreign Exchange Contract - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2015
Derivatives Designated for Hedge Accounting
Derivative [Line Items]
Notional values designated for hedge accounting	$ 399		$ 399		$ 399
Derivatives not Designated for Hedge Accounting
Derivative [Line Items]
Notional values designated for hedge accounting	1,878		1,878		$ 1,755
Net losses from changes in fair value not designated for hedge accounting	$ 24	$ 24	$ 2	$ 74