Income Taxes (Tables)

9 Months Ended

Sep. 30, 2015

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	2015			2014			2015			2014
Income tax expense (benefit)	$	(917	)	$	627		$	(2,232	)	$	1,719
Income (loss) before income taxes	(3,077		)	1,774			(7,520		)	506
Effective tax rate	30		%	35		%	30		%	340		%