Income Taxes	3 Months Ended
Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	5. INCOME TAXES Income tax provisions for interim (quarterly) periods are based on an estimated annual effective income tax rate calculated separately from the effect of significant, infrequent or unusual items. Income tax expense was $13 million and $2 million for the three months ended March 31, 2016 and 2015, respectively. The increase in income tax expense was driven by a reduction in discrete benefits in the three months ended March 31, 2016 and by an unfavorable mix in earnings.

Income Taxes

3 Months Ended

Mar. 31, 2016

5. INCOME TAXES

Income tax provisions for interim (quarterly) periods are based on an estimated annual effective income tax rate calculated separately from the effect of significant, infrequent or unusual items. Income tax expense was $13 million and $2 million for the three months ended March 31, 2016 and 2015, respectively. The increase in income tax expense was driven by a reduction in discrete benefits in the three months ended March 31, 2016 and by an unfavorable mix in earnings.