Commitments and Contingencies (Schedule of Reconciliation of the Beginning and Ending Liability Balances in Connection with Probable Contingencies) (Details) - Pending Litigation [Member] - Other Probable Contingencies [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Loss Contingency Accrual [Roll Forward]
Beginning Balance	$ 14	$ 14
Expense	7	14
Reserve for insured claim	4
Cash payments	(6)	(14)
Ending Balance	$ 19	$ 14