Restructuring and Transaction Costs and Other Expenses (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Restructuring Cost And Reserve [Line Items]
Restructuring and transaction costs	$ 94	$ 94
Foreign currency realized loss	(244)
Foreign currency unrealized losses	(254)
Reduction of workforce [Member]
Restructuring Cost And Reserve [Line Items]
Expense associated with accelerated awards	26
Reduction of workforce [Member] | Employee Related Costs [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring and transaction costs	94
Reduction of workforce [Member] | Estimated Defined Benefit Settlements [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring and transaction costs	$ 15