Income Taxes (Tables)

9 Months Ended

Sep. 30, 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						Nine Months Ended
	September 30,						September 30,
millions except percentages	2018			2017			2018			2017
Current income tax expense (benefit)	$	146		$	430		$	383		$	670
Deferred income tax expense (benefit)	110			(855		)	124			(1,036		)
Total income tax expense (benefit)	$	256		$	(425	)	$	507		$	(366	)
Income (loss) before income taxes	683			(1,066		)	1,125			(1,616		)
Effective tax rate	37		%	40		%	45		%	23		%