CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (unaudited) - USD ($) $ in Millions		Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Loss	Treasury Stock		Total DXC Equity	Non- Controlling Interest
Balance (in shares) at Mar. 31, 2017			141,299,000
Balance at Mar. 31, 2017		$ 2,166	$ 1	$ 2,219	$ (170)	$ (162)	$ 0		$ 1,888	$ 278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Business acquired in purchase, net of issuance costs (in shares)	[1]		141,741,000
Business acquired in purchase, net of issuance costs	[1]	9,905	$ 2	9,848					9,850	55
Net income		1,217			1,191				1,191	26
Other comprehensive income (loss)		52				44			44	8
Share-based compensation expense		74		74					74
Acquisition of treasury stock		(83)					(83)		(83)
Share repurchase program (in shares)			(842,000)
Share repurchase program		(66)		(36)	(30)				(66)
Stock option exercises and other common stock transactions (in shares)			4,356,000
Stock option exercises and other common stock transactions		96		96					96
Dividends declared		(157)			(157)				(157)
Non-controlling interest distributions and other		(2)								(2)
Balance (in shares) at Dec. 31, 2017			286,554,000
Balance at Dec. 31, 2017		$ 13,202	$ 3	12,201	834	(118)	(83)		12,837	365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared (in dollars per share)		$ 0.54
Balance (in shares) at Sep. 30, 2017			285,943,000
Balance at Sep. 30, 2017		$ 12,507	$ 3	12,158	110	(70)	(61)		12,140	367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Business acquired in purchase, net of issuance costs	[1]	(6)								(6)
Net income		779			776				776	3
Other comprehensive income (loss)		(45)				(48)			(48)	3
Share-based compensation expense		17		17					17
Acquisition of treasury stock		(22)					(22)		(22)
Stock option exercises and other common stock transactions (in shares)			611,000
Stock option exercises and other common stock transactions		26		26					26
Dividends declared		(52)			(52)				(52)
Non-controlling interest distributions and other		(2)								(2)
Balance (in shares) at Dec. 31, 2017			286,554,000
Balance at Dec. 31, 2017		$ 13,202	$ 3	12,201	834	(118)	(83)		12,837	365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared (in dollars per share)		$ 0.18
Cumulative effect of adopting the new revenue standard		$ 114			114				114
Treasury shares		1,016,947
Balance (in shares) at Mar. 31, 2018			286,393,000
Balance at Mar. 31, 2018		$ 13,837	$ 3	12,210	1,301	58	(85)	[2]	13,487	350
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		991			983				983	8
Other comprehensive income (loss)		(522)				(522)			(522)
Share-based compensation expense		57		57					57
Acquisition of treasury stock		(49)					(49)	[2]	(49)
Share repurchase program (in shares)			(17,680,000)
Share repurchase program		(1,248)		(776)	(472)				(1,248)
Stock option exercises and other common stock transactions (in shares)			2,919,000
Stock option exercises and other common stock transactions		29		29					29
Dividends declared		(161)			(161)				(161)
Non-controlling interest distributions and other		(24)							0	(24)
Divestiture of USPS		(1,668)		(177)	(1,491)				(1,668)
Balance (in shares) at Dec. 31, 2018			271,632,000
Balance at Dec. 31, 2018		$ 11,356	$ 3	11,343	274	(464)	(134)	[2]	11,022	334
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared (in dollars per share)		$ 0.57
Balance (in shares) at Sep. 30, 2018			282,519,000
Balance at Sep. 30, 2018		$ 11,837	$ 3	11,848	136	(382)	(105)	[2]	11,500	337
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		466			462				462	4
Other comprehensive income (loss)		(77)				(82)			(82)	5
Share-based compensation expense		17		17					17
Acquisition of treasury stock		(29)					(29)	[2]	(29)
Share repurchase program (in shares)			(12,452,000)
Share repurchase program		(797)		(525)	(272)				(797)
Stock option exercises and other common stock transactions (in shares)			1,565,000
Stock option exercises and other common stock transactions		3		3					3
Dividends declared		(52)			(52)				(52)
Non-controlling interest distributions and other		(12)							0	(12)
Balance (in shares) at Dec. 31, 2018			271,632,000
Balance at Dec. 31, 2018		$ 11,356	$ 3	$ 11,343	$ 274	$ (464)	$ (134)	[2]	$ 11,022	$ 334
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared (in dollars per share)		$ 0.19
Treasury shares		1,754,722

[1] See Note 3 - "Acquisitions"

[2] 1,754,722 treasury shares as of December 31, 2018