Contingencies (Schedule of Reconciliation of the Beginning and Ending Liability Balances in Connection with Probable Contingencies) (Details) - Pending Litigation [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
CVR Related Liability at Fair Value [Member]
Loss Contingency Accrual [Roll Forward]
Beginning Balance	$ 256
Expense	3
Cash payments
Ending Balance	259
Other Probable Contingencies [Member]
Loss Contingency Accrual [Roll Forward]
Beginning Balance	14
Expense	5
Cash payments	(2)
Ending Balance	$ 17