Segment Information (Net Revenue By Geographic Area) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Revenue from External Customer [Line Items]
Total net revenue	$ 1,070	$ 1,126	$ 3,088	$ 3,330
North America
Revenue from External Customer [Line Items]
Net revenue from unaffiliated customers	448	473	1,335	1,428
International
Revenue from External Customer [Line Items]
Net revenue from unaffiliated customers	$ 622	$ 653	$ 1,753	$ 1,902