CONSOLIDATED COMBINED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions		2 Months Ended	3 Months Ended								5 Months Ended		10 Months Ended	12 Months Ended
	May 31, 2018	May 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017		Mar. 31, 2019	Mar. 31, 2019		Mar. 31, 2018		Oct. 31, 2016
Income Statement [Abstract]
Revenue			$ 1,094	$ 1,075	$ 1,068	$ 793	$ 715	$ 722	$ 706	$ 676	$ 1,073			$ 4,030		$ 2,819		$ 2,732
Costs of services			817	816	813	597	523	550	557	525	820			3,043		2,155		2,086
Selling, general and administrative			74	76	89	61	50	51	35	46	77			300		182		207
Depreciation and amortization			116	76	74	64	51	46	33	37	73			330		167		225
Restructuring costs			7	1	2	0	4	3	4	3	0			10		14		20
Separation and integration-related costs			22	19	21	44	46	27	6	11	34			106		90		34
Interest expense, net			37	37	37	10	5	0	5	2	10			121		12		31
Other expense, net			34	2	(4)	(24)					0			8		0		0
Total costs and expenses			1,107	1,027	1,032	752	679	677	640	624	1,014			3,918		2,620		2,603
Income before taxes			(13)	48	36	41	36	45	66	52	59			112		199		129
Income tax expense (benefit)			6	10	12	12	4	(59)	26	20	23			40		(9)		49
Net income		$ 49	$ (19)	$ 38	$ 24	$ 29	$ 32	$ 104	$ 40	$ 32	$ 36		$ 23	$ 72		$ 208		$ 80
Earnings per common share
Basic EPS (in dollars per share)			$ (0.12)	$ 0.23	$ 0.15	$ 0.18	$ 0.22	$ 0.73	$ 0.28	$ 0.22	$ 0.25	[1]		$ 0.44	[1]	$ 1.46	[1]	$ 0.56	[1]
Diluted EPS (in dollars per share)			$ (0.12)	$ 0.23	$ 0.14	$ 0.17	$ 0.22	$ 0.73	$ 0.28	$ 0.22	$ 0.25	[1]		$ 0.44	[1]	$ 1.46	[1]	$ 0.56	[1]
Number of shares from distribution in a spinoff (in shares)	165,700										142,430			164,560		142,430		142,430

[1] (1) Earnings per common share information for the fiscal year ended March 31, 2018, the five months ended March 31, 2017, and the fiscal year ended October 31, 2016 is computed using the 142.43 million shares of Perspecta common stock resulting from the Distribution as Perspecta did not operate as a stand-alone entity during the period, and therefore, no Perspecta common stock, stock options or other equity awards were outstanding and no dividends were declared or paid by Perspecta.