Debt (Subsidiary Non-Recourse Debt in Default or Accelerated) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Debt Details [Line Items]
Debt default amount	$ 128
Kavarna (Bulgaria) | Covenant Violation
Debt Details [Line Items]
Net assets	78
Debt Default, Short-term Debt, Amount	123
Sogrinsk [Member] | Covenant Violation
Debt Details [Line Items]
Net assets	9
Debt Default, Short-term Debt, Amount	$ 5