Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation, net of income taxes of $2 million and $1 million at September 29, 2017 and June 30, 2017, respectively	$ (88)		$ (113)
Net unrealized loss on hedging derivatives, net of income taxes of $11 million at September 29, 2017 and June 30, 2017	(16)		(17)
Unrecognized postretirement obligations, net of income taxes of $89 million at September 29, 2017 and June 30, 2017	(146)		(146)
Accumulated other comprehensive loss	(250)		(276)
Tax effect on foreign currency translation	2	$ 1
Tax effect on unrealized loss on hedging derivatives	11	11
Tax effect on unrecognized post-retirement obligations	$ 89	$ 89
Accumulated Foreign Currency Adjustment Attributable to Parent | Discontinued Operations, Disposed of by Sale | IT Services and CapRock
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated foreign currency translation loss reclassified to earnings, net of tax			52
Accumulated foreign currency translation loss reclassified to earnings, tax			$ (14)