Income Taxes (Tables)

9 Months Ended

Sep. 30, 2017

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   September 30,						Nine Months Ended   September 30,
millions except percentages	2017			2016			2017			2016
Current income tax expense (benefit)	$	430		$	64		$	670		$	212
Deferred income tax expense (benefit)	(855		)	(324		)	(1,036		)	(1,169		)
Total income tax expense (benefit)	$	(425	)	$	(260	)	$	(366	)	$	(957	)
Income (loss) before income taxes	(1,066		)	(1,007		)	(1,616		)	(3,313		)
Effective tax rate	40		%	26		%	23		%	29		%