Income Taxes And Tax-Related Items Income Taxes And Tax-Related Items (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 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 | 10 | 10 |
| Net deferred tax assets | 165 | 141 |
| Increase in net deferred tax assets | 24 | |
| 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 |