Income Taxes (Tables)

3 Months Ended

Mar. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Income Taxes and Effective Tax Rate

The following summarizes income tax expense (benefit) and effective tax rates:

	Three Months Ended   March 31,
millions except percentages	2018			2017
Current income tax expense (benefit)	$	90		$	762
Deferred income tax expense (benefit)	36			(665		)
Total income tax expense (benefit)	$	126		$	97
Income (loss) before income taxes	300			(178		)
Effective tax rate	42		%	(54		)%