Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 29, 2019	Mar. 30, 2018	Mar. 29, 2019	Mar. 30, 2018
Pension
Net periodic benefit income
Service cost	$ 9	$ 10	$ 27	$ 29
Interest cost	52	49	157	146
Expected return on plan assets	(95)	(92)	(286)	(276)
Amortization of net actuarial gain	0	0	0	0
Total net periodic benefit income	(34)	(33)	(102)	(101)
Other Benefits
Net periodic benefit income
Service cost	1	0	1	1
Interest cost	2	1	6	5
Expected return on plan assets	(4)	(4)	(12)	(12)
Amortization of net actuarial gain	(2)	0	(5)	(1)
Total net periodic benefit income	$ (3)	$ (3)	$ (10)	$ (7)