CONDENSED CONSOLIDATED COMBINED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (unaudited) - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Parent Company Investment
Beginning balance at Mar. 31, 2017	$ 416						$ 416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effects of purchase accounting	2,434						2,434
Net income	32						32
Transfers to Parent, net	(77)						(77)
Ending balance at Jun. 30, 2017	2,805						2,805
Beginning balance at Mar. 31, 2017	416						416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	176
Ending balance at Dec. 31, 2017	2,843						2,843
Beginning balance at Jun. 30, 2017	2,805						2,805
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	40						40
Transfers to Parent, net	(108)						(108)
Ending balance at Sep. 30, 2017	2,737						2,737
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	104						104
Transfers to Parent, net	2						2
Ending balance at Dec. 31, 2017	2,843						2,843
Beginning balance (in shares) at Mar. 31, 2018		0
Beginning balance at Mar. 31, 2018	2,729	$ 0	$ 0	$ 0	$ 0	$ 0	2,729
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	49						49
Transfers to Parent, net	(145)						(145)
Dividend to DXC prior to May 31, 2018	(984)		(984)
Ending balance (in shares) at May. 31, 2018		0
Ending balance at May. 31, 2018	2,637	$ 0	0	0	0	0	2,637
Beginning balance (in shares) at Mar. 31, 2018		0
Beginning balance at Mar. 31, 2018	2,729	$ 0	0	0	0	0	2,729
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Spin-Off activity (in shares)		142,426,000
Spin-Off activity	0	$ 2	2,635				(2,637)
Mergers activity (in shares)		23,273,000
Mergers activity	578		578
Other comprehensive income (loss)	(1)				(1)
Dividends declared ($0.05 per share)	(8)		(8)
Ending balance (in shares) at Jun. 30, 2018		165,699,000
Ending balance at Jun. 30, 2018	2,202	$ 2	2,221	(20)	(1)	0	0
Beginning balance (in shares) at Mar. 31, 2018		0
Beginning balance at Mar. 31, 2018	2,729	$ 0	0	0	0	0	2,729
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	91
Stock-based compensation	$ 7
Repurchases of common stock (in shares)	(1,890,428)
Repurchases of common stock	$ (44)
Ending balance (in shares) at Dec. 31, 2018		163,902,000
Ending balance at Dec. 31, 2018	2,197	$ 2	2,224	29	(13)	(45)	0
Beginning balance (in shares) at May. 31, 2018		0
Beginning balance at May. 31, 2018	2,637	$ 0	0	0	0	0	2,637
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(20)			(20)
Ending balance (in shares) at Jun. 30, 2018		165,699,000
Ending balance at Jun. 30, 2018	2,202	$ 2	2,221	(20)	(1)	0	0
Beginning balance (in shares) at May. 31, 2018		0
Beginning balance at May. 31, 2018	2,637	$ 0	0	0	0	0	2,637
Ending balance (in shares) at Dec. 31, 2018		163,902,000
Ending balance at Dec. 31, 2018	2,197	$ 2	2,224	29	(13)	(45)	0
Beginning balance (in shares) at Jun. 30, 2018		165,699,000
Beginning balance at Jun. 30, 2018	2,202	$ 2	2,221	(20)	(1)	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24			24
Other comprehensive income (loss)	6				6
Stock-based compensation	1		1
Repurchases of common stock (in shares)		(923,000)
Repurchases of common stock	(23)					(23)
Stock option exercises and other common stock transactions (in shares)		43,000
Stock option exercises and other common stock transactions	1		1
Dividends declared ($0.05 per share)	(8)		(4)	(4)
Ending balance (in shares) at Sep. 30, 2018		164,819,000
Ending balance at Sep. 30, 2018	2,203	$ 2	2,219	0	5	(23)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	38			38
Other comprehensive income (loss)	(18)				(18)
Stock-based compensation	$ 4		4
Repurchases of common stock (in shares)	(967,240)	(967,000)
Repurchases of common stock	$ (21)					(21)
Stock option exercises and other common stock transactions (in shares)		50,000
Stock option exercises and other common stock transactions	0		1			(1)
Dividends declared ($0.05 per share)	(9)			(9)
Ending balance (in shares) at Dec. 31, 2018		163,902,000
Ending balance at Dec. 31, 2018	$ 2,197	$ 2	$ 2,224	$ 29	$ (13)	$ (45)	$ 0