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 (shares)		1
Issuance of shares under employee plans	35		46				$ (11)
Share-based compensation	71		71
Payments to noncontrolling interests	(143)							(143)
Other comprehensive income (loss)	(109)					(109)
Net income (loss)	965				830			135
Repurchase of common stock (shares)							(10)
Repurchase of common stock	(1,377)		85				$ (1,462)
Retirement of common stock (shares)		(5)					4
Retirement of common stock	(1)		(70)		(472)		$ 541
Cash dividends declared	(222)				(222)
Other	(41)		1	(1)				(41)
Ending balance (shares) at Dec. 31, 2018		271
Ending balance (shares) at Dec. 31, 2018							(79)
Ending balance at Dec. 31, 2018	9,389	$ 3	6,321	(2)	13,276	(1,826)	$ (8,587)	204
Beginning balance (shares) at Sep. 30, 2018		275
Beginning balance (shares) at Sep. 30, 2018							(80)
Beginning balance at Sep. 30, 2018	9,534	$ 3	6,411	(2)	13,354	(1,762)	$ (8,678)	208
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans (shares)		1
Issuance of shares under employee plans	8		8				$ 0
Share-based compensation	22		22
Payments to noncontrolling interests	(37)							(37)
Other comprehensive income (loss)	(64)					(64)
Net income (loss)	515				469			46
Repurchase of common stock (shares)							(3)
Repurchase of common stock	(500)		(50)				$ (450)
Retirement of common stock (shares)		(5)					4
Retirement of common stock	(1)		(70)		(472)		$ 541
Cash dividends declared	(75)				(75)
Other	(13)							(13)
Ending balance (shares) at Dec. 31, 2018		271
Ending balance (shares) at Dec. 31, 2018							(79)
Ending balance at Dec. 31, 2018	$ 9,389	$ 3	6,321	(2)	13,276	(1,826)	$ (8,587)	204
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	72		89				$ (17)
Share-based compensation	90		90
Payments to noncontrolling interests	(115)							(115)
Other comprehensive income (loss)	186					186
Net income (loss)	9				(121)			130
Repurchase of common stock (shares)							(14)
Repurchase of common stock	(1,934)						$ (1,934)
Cash dividends declared	(221)				(221)
Other	$ 0				(3)			3
Ending balance (shares) at Dec. 31, 2019		272
Ending balance (shares) at Dec. 31, 2019	(95)						(95)
Ending balance at Dec. 31, 2019	$ 6,385	$ 3	6,614	(2)	12,075	(1,663)	$ (10,853)	211
Beginning balance (shares) at Sep. 30, 2019		272
Beginning balance (shares) at Sep. 30, 2019							(92)
Beginning balance at Sep. 30, 2019	6,692	$ 3	6,573	(2)	11,965	(1,704)	$ (10,353)	210
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans	11		11
Share-based compensation	30		30
Payments to noncontrolling interests	(39)							(39)
Other comprehensive income (loss)	41					41
Net income (loss)	231				186			45
Repurchase of common stock (shares)							(3)
Repurchase of common stock	(500)						$ (500)
Cash dividends declared	(73)				(73)
Other	$ (8)				(3)			(5)
Ending balance (shares) at Dec. 31, 2019		272
Ending balance (shares) at Dec. 31, 2019	(95)						(95)
Ending balance at Dec. 31, 2019	$ 6,385	$ 3	$ 6,614	$ (2)	$ 12,075	$ (1,663)	$ (10,853)	$ 211