Income Taxes (Tables)

3 Months Ended

Mar. 31, 2014

Table Text Block [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	2014			2013
Income tax expense (benefit)	$	664		$	456
Effective tax rate	(34		)%	49		%