Employee Benefits (Details Textual) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Pre-Medicare company contribution for retiree medical coverage, maximum percent	4.00%
Contribution to other post retirement plans	$ 125
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, contributions by employer to employee pension plan	941
Defined benefit plan, estimated future employer contributions in next fiscal year beginning after the date of the latest statement of financial position	1,050
Pension Benefits | United States
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, contributions by employer to employee pension plan	788
Defined benefit plan, estimated future employer contributions in next fiscal year beginning after the date of the latest statement of financial position	800
Pension Benefits | International
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, estimated future employer contributions in next fiscal year beginning after the date of the latest statement of financial position	250
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions during the remaining of fiscal year	$ 50