CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Other Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury	Noncontrolling Interests
Beginning balance (shares) at Mar. 31, 2018		275
Beginning balance (shares) at Mar. 31, 2018							(73)
Beginning balance at Mar. 31, 2018	$ 10,057	$ 3	$ 6,188	$ (1)	$ 12,986	$ (1,717)	$ (7,655)	$ 253
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans	27		38				$ (11)
Share-based compensation	49		49
Payments to noncontrolling interests	(106)							(106)
Other comprehensive income (loss)	(45)					(45)
Net income (loss)	450				361			89
Repurchase of common stock (shares)							(7)
Repurchase of common stock	(877)		135				$ (1,012)
Cash dividends declared	(147)				(147)
Other	(28)		1	(1)				(28)
Ending balance (shares) at Sep. 30, 2018		275
Ending balance (shares) at Sep. 30, 2018							(80)
Ending balance at Sep. 30, 2018	9,534	$ 3	6,411	(2)	13,354	(1,762)	$ (8,678)	208
Beginning balance (shares) at Jun. 30, 2018		275
Beginning balance (shares) at Jun. 30, 2018							(76)
Beginning balance at Jun. 30, 2018	9,647	$ 3	6,372	(1)	12,932	(1,801)	$ (8,098)	240
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans	16		16
Share-based compensation	24		24
Payments to noncontrolling interests	(42)							(42)
Other comprehensive income (loss)	39					39
Net income (loss)	542				499			43
Repurchase of common stock (shares)							(4)
Repurchase of common stock	(580)						$ (580)
Cash dividends declared	(78)				(78)
Other	(34)		(1)	(1)	1			(33)
Ending balance (shares) at Sep. 30, 2018		275
Ending balance (shares) at Sep. 30, 2018							(80)
Ending balance at Sep. 30, 2018	$ 9,534	$ 3	6,411	(2)	13,354	(1,762)	$ (8,678)	208
Beginning balance (shares) at Mar. 31, 2019		271
Beginning balance (shares) at Mar. 31, 2019	(81)						(81)
Beginning balance at Mar. 31, 2019	$ 8,287	$ 3	6,435	(2)	12,409	(1,849)	$ (8,902)	193
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans (shares)		1
Issuance of shares under employee plans	61		78				$ (17)
Share-based compensation	60		60
Payments to noncontrolling interests	(76)							(76)
Other comprehensive income (loss)	145					145
Net income (loss)	(222)				(307)			85
Repurchase of common stock (shares)							(11)
Repurchase of common stock	(1,434)						$ (1,434)
Cash dividends declared	(148)				(148)
Other	$ 8							8
Ending balance (shares) at Sep. 30, 2019		272
Ending balance (shares) at Sep. 30, 2019	(92)						(92)
Ending balance at Sep. 30, 2019	$ 6,692	$ 3	6,573	(2)	11,965	(1,704)	$ (10,353)	210
Beginning balance (shares) at Jun. 30, 2019		271
Beginning balance (shares) at Jun. 30, 2019							(86)
Beginning balance at Jun. 30, 2019	8,068	$ 3	6,483	(1)	12,770	(1,778)	$ (9,603)	194
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans (shares)		1
Issuance of shares under employee plans	56		56
Share-based compensation	34		34
Payments to noncontrolling interests	(37)							(37)
Other comprehensive income (loss)	74					74
Net income (loss)	(688)				(730)			42
Repurchase of common stock (shares)							(6)
Repurchase of common stock	(750)						$ (750)
Cash dividends declared	(75)				(75)
Other	$ 10			(1)				11
Ending balance (shares) at Sep. 30, 2019		272
Ending balance (shares) at Sep. 30, 2019	(92)						(92)
Ending balance at Sep. 30, 2019	$ 6,692	$ 3	$ 6,573	$ (2)	$ 11,965	$ (1,704)	$ (10,353)	$ 210