Postretirement Benefit Plans - Components of Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Mar. 31, 2017	Jul. 01, 2016	Apr. 01, 2016	Mar. 31, 2017	Apr. 01, 2016
Net periodic benefit income
Service cost	$ 16		$ 19	$ 45	$ 60
Interest cost	48		66	144	196
Expected return on plan assets	(90)		(91)	(268)	(271)
Amortization of net actuarial loss			0		2
Amortization of prior service cost			0		(7)
Net periodic benefit income			(6)		(20)
Effect of curtailments or settlements			0		(121)
Total net periodic benefit income	(26)		(6)	(79)	(141)
Pension
Net periodic benefit income
Service cost	15		18	44	56
Interest cost	46		63	138	186
Expected return on plan assets	(85)		(87)	(255)	(258)
Amortization of net actuarial loss			0		0
Amortization of prior service cost			0		0
Net periodic benefit income			(6)		(16)
Effect of curtailments or settlements			0		0
Total net periodic benefit income	(24)		(6)	(73)	(16)
Other Benefits
Net periodic benefit income
Service cost	1		1	1	4
Interest cost	2		3	6	10
Expected return on plan assets	(5)		(4)	(13)	(13)
Amortization of net actuarial loss			0		2
Amortization of prior service cost			0		(7)
Net periodic benefit income			0		(4)
Effect of curtailments or settlements			0		(121)
Total net periodic benefit income	$ (2)		$ 0	$ (6)	$ (125)
Net liability reduction for certain post-employment benefit plans		$ (101)