Stockholder's Equity (Stock Repurchase Program) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended	4 Months Ended	6 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2015		May. 28, 2015
Treasury Stock Transactions, Excluding Value of Shares Reissued [Abstract]
Stock repurchase program, authorized amount					$ 500
Purchase of treasury stock	2,800	3,800	3,764	[1]
Treasury stock acquired, average cost per share	$ 97.98	$ 99.54
Stock repurchase program, remaining authorized repurchase amount	$ 125	$ 125	$ 125

[1] Refer to “Stock Repurchase Program” section below for details.