Postretirement Benefit Plans - Components of Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Dec. 29, 2017	Dec. 30, 2016
Net periodic benefit income
Service cost	$ 10	$ 14	$ 20	$ 29
Interest cost	51	48	101	96
Expected return on plan assets	(96)	(89)	(192)	(178)
Amortization of net actuarial loss	(1)		(1)
Total net periodic benefit income	(36)	(27)	(72)	(53)
Discontinued operations, net of income taxes
Net periodic benefit income
Total net periodic benefit income		1		1
Pension
Net periodic benefit income
Service cost	9	14	19	29
Interest cost	49	46	97	92
Expected return on plan assets	(92)	(85)	(184)	(170)
Amortization of net actuarial loss	0		0
Total net periodic benefit income	(34)	(25)	(68)	(49)
Other Benefits
Net periodic benefit income
Service cost	1	0	1	0
Interest cost	2	2	4	4
Expected return on plan assets	(4)	(4)	(8)	(8)
Amortization of net actuarial loss	(1)		(1)
Total net periodic benefit income	$ (2)	$ (2)	$ (4)	$ (4)