Post-Employment Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plans
Defined benefit plan net periodic benefit cost
Service cost - benefits earned during the period	$ 68	$ 62	$ 150	$ 128
Interest cost on projected benefit obligations	77	75	156	152
Expected return on plan assets	(128)	(113)	(257)	(226)
Actuarial loss, net	42	24	89	49
Prior service cost (credit)				1
Total Cost	59	48	138	104
Net amortization of:
Company contributions			547	330
Defined Benefit Plans | Discontinued operations
Defined benefit plan net periodic benefit cost
Total Cost		4	1	8
Defined Benefit Plans | Continuing operations
Defined benefit plan net periodic benefit cost
Total Cost	59	44	137	96
Medical and Dental Plans
Defined benefit plan net periodic benefit cost
Service cost - benefits earned during the period	6	9	15	18
Interest cost on projected benefit obligations	11	16	25	32
Expected return on plan assets	(10)	(9)	(19)	(19)
Actuarial loss, net	1	4	10	9
Prior service cost (credit)	(12)	(9)	(24)	(18)
Total Cost	(4)	11	7	22
Net amortization of:
Company contributions			24	40
Medical and Dental Plans | Continuing operations
Defined benefit plan net periodic benefit cost
Total Cost	$ (4)	$ 11	$ 7	$ 22