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, 2013	$ 5,450	$ 59	$ 3,593	$ 5,357	$ (155)	$ (3,404)
Net income	914			914
Other comprehensive income (loss)	(16)				(16)
Comprehensive income	898
Share-based compensation	82		82
Dividends declared	(453)			(453)
Release of restricted stock, exercise of common stock options, ESPP and other items	98		(65)			163
Treasury stock purchased	(505)					(505)
Ending balance at Mar. 31, 2014	5,570	59	3,610	5,818	(171)	(3,746)
Net income	846			846
Other comprehensive income (loss)	(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 income (loss)	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)