Unaudited Quarterly Operating Results

12 Months Ended

Dec. 31, 2012

Unaudited Quarterly Operating Results [Abstract]

Quarterly Financial Information [Text Block]

(20) Unaudited Quarterly Operating Results (in millions)



	Three-Month Periods Ended
	March 31,		June 30,		September 30,		December 31,
	2012		2012		2012		2012

Operating revenue	$	1,191	$	1,153	$	1,327	$	1,211
Operating income	278		251		378		114
Net income	151		130		212		44



	Three-Month Periods Ended
	March 31,		June 30,		September 30,		December 31,
	2011		2011		2011		2011

Operating revenue	$	1,119	$	1,091	$	1,198	$	1,178
Operating income	267		263		316		238
Net income	127		129		169		130

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

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