Employee Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Net Periodic Benefit Cost
Net Periodic Other Benefit Costs	$ 362	$ 341	$ 912	$ 880
Pension Benefits | United States
Net Periodic Benefit Cost
Service cost	122	123	366	370
Interest cost	91	95	274	283
Expected return on plan assets	(149)	(181)	(447)	(542)
Amortization of prior service credits	(1)	(2)	(3)	(6)
Amortization of actuarial losses	85	84	255	251
Settlement losses	169	162	325	324
Net Periodic Other Benefit Costs	317	281	770	680
Pension Benefits | International
Net Periodic Benefit Cost
Service cost	38	37	114	120
Interest cost	54	68	164	198
Expected return on plan assets	(61)	(61)	(178)	(184)
Amortization of prior service credits	3	1	9	11
Amortization of actuarial losses	11	14	33	37
Settlement losses	0	1	0	18
Net Periodic Other Benefit Costs	45	60	142	200
Other Benefits
Net Periodic Benefit Cost
Service cost	8	15	24	45
Interest cost	23	32	71	96
Amortization of prior service credits	(7)	3	(21)	10
Amortization of actuarial losses	(1)	5	(4)	15
Net Periodic Other Benefit Costs	$ 23	$ 55	$ 70	$ 166