Income Taxes Deferred Tax Assets, Balance Sheet Location (Details) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Deferred Tax Asset, Balance Sheet Location [Line Items] | ||
| Deferred Tax Assets, Net | $ 233 | |
| Deferred Tax Liabilities, Net | $ (14) | |
| Current Assets | ||
| Deferred Tax Asset, Balance Sheet Location [Line Items] | ||
| Deferred Tax Assets, Net | 0 | 171 |
| Current Liabilities | ||
| Deferred Tax Asset, Balance Sheet Location [Line Items] | ||
| Deferred Tax Assets, Net | 0 | |
| Deferred Tax Liabilities, Net | (8) | |
| Noncurrent Assets | ||
| Deferred Tax Asset, Balance Sheet Location [Line Items] | ||
| Deferred Tax Assets, Net | 238 | 232 |
| Noncurrent Liabilities | ||
| Deferred Tax Asset, Balance Sheet Location [Line Items] | ||
| Deferred Tax Liabilities, Net | $ (252) | $ (162) |