The Following Are Excerpts from the 2016 Form 10-K of Valero

The following are excerpts from the 2016 Form 10-K of Valero Energy. Use the information to answer the requirements.
Components of income tax expense related to continuing operations were as follows (in millions):
The tax effects of significant temporary differences representing deferred income tax assets and liabilities were as follows (in millions):
December 31,

a. What income tax expense does Valero Energy report in its 2016 income statement? How much of this expense is currently payable?
b. If Valero Energy had reported deferred tax liabilities related to "Property, plant and equipment," describe how these liabilities would have arisen. How likely is it that these liabilities would have been paid? Specifically, describe a scenario that would (i) defer these taxes indefinitely, and (ii) would result in these liabilities requiring payment within the near future.
c. Valero Energy reports a deferred tax asset relating to "Compensation and employee benefit liabilities." When a company has a pension plan it records an expense and related liability each year while the employee works for the company. Pension payments are not made to employees until they retire. Explain why pension plans create a deferred tax asset.
d. Valero Energy reports deferred tax assets from net loss carry forwards. Explain how these arise and how they will result in a future benefit.
e. Valero Energy reports a valuation allowance of $374 million in 2016 and of $435 million in 2015, which is deducted from the deferred tax assets. Why? How did the change in the allowance from 2015 to 2016 affect net income in 2016? How can a company use this allowance to meet its income targets in a particular year?