Pension Plans, Postretirement and Other Employee Benefits - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Pension
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Employer contributions, remainder of fiscal year	$ 10
Other Pension Plan
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Employer contributions	10
Non-cash contribution expense	6
Postretirement
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Employer contributions	8
Employer contributions, remainder of fiscal year	2
US | Pension
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Employer contributions	12
Foreign | Pension
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Employer contributions	$ 10