Provision (Benefit) for Income Taxes Reconciliation of Unrecognized Tax Benefits Table (Details) - USD ($) $ in Millions |
12 Months Ended | |
---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | ||
Balance at beginning of period | $ 55 | $ 89 |
Additions for tax positions of prior years | 0 | 2 |
Reductions for tax positions of prior years | (4) | 0 |
Changes due to currency translation | (1) | (36) |
Balance at end of period | $ 50 | $ 55 |