Postretirement Benefit Plans - Components of Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 30, 2018	Mar. 31, 2017	Mar. 30, 2018	Mar. 31, 2017
Net periodic benefit income
Service cost	$ 10	$ 16	$ 30	$ 45
Interest cost	50	48	151	144
Expected return on plan assets	(96)	(90)	(288)	(268)
Amortization of net actuarial gain	0		(1)
Total net periodic benefit income	(36)	(26)	(108)	(79)
Discontinued operations, net of income taxes
Net periodic benefit income
Total net periodic benefit income		1		2
Pension
Net periodic benefit income
Service cost	10	15	29	44
Interest cost	49	46	146	138
Expected return on plan assets	(92)	(85)	(276)	(255)
Amortization of net actuarial gain	0		0
Total net periodic benefit income	(33)	(24)	(101)	(73)
Other Benefits
Net periodic benefit income
Service cost	0	1	1	1
Interest cost	1	2	5	6
Expected return on plan assets	(4)	(5)	(12)	(13)
Amortization of net actuarial gain	0		(1)
Total net periodic benefit income	$ (3)	$ (2)	$ (7)	$ (6)