Commitments and Contingencies (Schedule of Reconciliation of the Beginning and Ending Liability Balances in Connection with Probable Contingencies) (Details) - Pending Litigation [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
CVR Related Liability at Fair Value [Member]
Loss Contingency Accrual [Roll Forward]
Beginning Balance	$ 252	$ 261
(Income) expense	4	(8)
Cash payments		(1)
Ending Balance	256	252
Other Probable Contingencies [Member]
Loss Contingency Accrual [Roll Forward]
Beginning Balance	14	10
(Income) expense	14	14
Reserve for insured claim		1
Cash payments	(14)	(11)
Ending Balance	$ 14	$ 14