Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income Tax Contingency [Line Items] | |||
| Interest on income taxes expense (less than) | $ 1 | $ 1 | $ 1 |
| Income tax penalties expense | 1 | 1 | 1 |
| Increase (decrease) in uncertain income tax positions | 1 | 1 | 1 |
| Federal | |||
| Income Tax Contingency [Line Items] | |||
| Unrecognized tax benefits | $ 1 | $ 1 | $ 1 |