Pension and Postretirement Benefit Plans - Components of net periodic benefit cost and other information 10Q (Details) - Funded - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Qualified and Non-qualified Pension Benefits | United States
Net periodic benefit cost (benefit)
Service cost	$ 67	$ 64	$ 201	$ 194
Interest cost	141	144	425	431
Expected return on plan assets	(259)	(261)	(777)	(782)
Amortization of prior service cost (benefit)	(5)	(6)	(17)	(18)
Amortization of net actuarial (gain) loss	97	89	291	265
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	41	30	123	90
Qualified and Non-qualified Pension Benefits | International
Net periodic benefit cost (benefit)
Service cost	33	35	100	102
Interest cost	38	45	112	131
Expected return on plan assets	(69)	(78)	(208)	(234)
Amortization of transition (asset) obligation				(1)
Amortization of prior service cost (benefit)	(3)	(3)	(9)	(10)
Amortization of net actuarial (gain) loss	29	21	89	66
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	28	20	84	54
Postretirement Benefits
Net periodic benefit cost (benefit)
Service cost	13	13	38	40
Interest cost	20	20	59	59
Expected return on plan assets	(21)	(23)	(63)	(68)
Amortization of prior service cost (benefit)	(13)	(13)	(39)	(41)
Amortization of net actuarial (gain) loss	14	15	42	46
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	$ 13	$ 12	$ 37	$ 36