Segment Information (Net Revenue By Geographic Area) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Revenue from External Customer [Line Items]
Net revenue	$ 1,185	$ 1,126	$ 990	$ 1,214	$ 1,123	$ 808	$ 695	$ 949	$ 4,515	$ 3,575	$ 3,797
North America [Member]
Revenue from External Customer [Line Items]
Net revenue from unaffiliated customers									1,956	1,510	1,701
International [Member]
Revenue from External Customer [Line Items]
Net revenue from unaffiliated customers									$ 2,559	$ 2,065	$ 2,096