Pension and Postretirement Benefit Plans - Components of net periodic benefit cost and other information 10Q (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
United States Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	$ 67	$ 65
Interest cost	142	143
Expected return on plan assets	(259)	(260)
Amortization of prior service cost (benefit)	(6)	(6)
Amortization of net actuarial (gain) loss	97	88
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	41	30
International Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	33	33
Interest cost	37	43
Expected return on plan assets	(69)	(78)
Amortization of prior service cost (benefit)	(3)	(3)
Amortization of net actuarial (gain) loss	30	22
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	28	17
Postretirement Benefits
Net periodic benefit cost (benefit)
Service cost	13	13
Interest cost	19	20
Expected return on plan assets	(21)	(23)
Amortization of prior service cost (benefit)	(13)	(14)
Amortization of net actuarial (gain) loss	14	16
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	$ 12	$ 12