Pensions and Other Postretirement Benefits (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected future employer contributions, excluding settlment losses	$ 30		$ 30
Pension settlement charges, pre tax	0	$ 0	0	$ 22
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected future employer contributions, excluding settlment losses	40		40
Pension settlement charges, pre tax	0	0	0	22
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected future employer contributions, excluding settlment losses	10		10
U.S. Non-qualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash payment to retirees - U.S. Non-qualified Pension Plan				40
UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to defined benefit pension plans	0	0	25	29
Foreign Plan | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer mandatory contributions	10		10
Foreign Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer mandatory contributions	20		20
U.S. Non-qualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension settlement charges, pre tax				22
Noncash Pension Settlement Charge - after tax				14
Mandatory Contribution | Foreign Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to defined benefit pension plans	$ 5	$ 3	$ 10	$ 8