Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance at Mar. 31, 2014	$ 5,570	$ 59	$ 3,610	$ 5,818	$ (171)	$ (3,746)
Net income	846			846
Other comprehensive (loss) income	(247)				(247)
Comprehensive income	599
Share-based compensation	87		87
Dividends declared	(444)			(444)
Release of restricted stock, exercise of common stock options, ESPP and other items	28		(66)	1		93
Treasury stock purchased	(215)					(215)
Ending balance at Mar. 31, 2015	5,625	59	3,631	6,221	(418)	(3,868)
Net income	783			783
Other comprehensive (loss) income	2				2
Comprehensive income	785
Share-based compensation	97		97
Dividends declared	(429)			(429)
Release of restricted stock, exercise of common stock options, ESPP and other items	7		(64)			71
Treasury stock purchased	(707)					(707)
Ending balance at Mar. 31, 2016	5,378	59	3,664	6,575	(416)	(4,504)
Net income	775			775
Other comprehensive (loss) income	(67)				(67)
Comprehensive income	708
Share-based compensation	108		108
Dividends declared	(428)			(428)
Release of restricted stock, exercise of common stock options, ESPP and other items	23		(70)	1		92
Treasury stock purchased	(100)					(100)
Ending balance at Mar. 31, 2017	$ 5,689	$ 59	$ 3,702	$ 6,923	$ (483)	$ (4,512)