Employee Benefits - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 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	$ 120
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, contributions by employer to employee pension plan	895
Pension Benefits | United States
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, contributions by employer to employee pension plan	726
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions during the remaining of fiscal year	$ 54