Employee Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Benefits
Net Periodic Benefit Cost
Net Periodic Other Benefit Costs	$ 216	$ 229
Pension Benefits | United States
Net Periodic Benefit Cost
Service cost	101	120
Interest cost	99	92
Expected return on plan assets	(141)	(159)
Amortization of prior service costs (credits)	0	1
Amortization of actuarial losses (gains)	60	76
Settlement losses	60	66
Net Periodic Other Benefit Costs	179	196
Pension Benefits | International
Net Periodic Benefit Cost
Service cost	35	40
Interest cost	51	46
Expected return on plan assets	(58)	(66)
Amortization of prior service costs (credits)	3	2
Amortization of actuarial losses (gains)	5	11
Settlement losses	1	0
Net Periodic Other Benefit Costs	37	33
Other Benefits
Net Periodic Benefit Cost
Service cost	9	13
Interest cost	24	21
Amortization of prior service costs (credits)	(7)	(7)
Amortization of actuarial losses (gains)	(1)	4
Net Periodic Other Benefit Costs	$ 25	$ 31