Income Taxes And Tax-Related Items Income Taxes And Tax-Related Items (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Unrecognized tax benefits	$ 10	$ 10
Reasonably possible decrease in unrecognized tax benefits in next 12 months	1
Tax-related interest and penalties payable	11	10
Net deferred tax assets	153	141
Increase in net deferred tax assets	12
State net operating loss carryforwards	4	4
Valuation allowance for deferred tax assets	$ 3	$ 3
Minimum
Years state net operating loss carryforwards expire	Dec. 31, 2018
Maximum
Years state net operating loss carryforwards expire	Dec. 31, 2027