Business Segment Information (Details Textuals) (USD $)	3 Months Ended
	Mar. 31, 2012 Segment	Mar. 31, 2011
Business Segment Information [Abstract]
Number of segments	6
Operating revenues from U.S. Operations	$ 11,300,000,000	$ 10,900,000,000
Percent of Operating revenues from U.S. Operations representative of consolidated operating revenues	68.00%	70.00%
Segment Reporting Information [Line Items]
Prior period operating earnings reclassifications to conform with current period presentation		23,000,000
Prior period adjustment to operating earnings tax expense		14,000,000
Latin America [Member]
Segment Reporting Information [Line Items]
Prior period operating earnings reclassifications to conform with current period presentation		(4,000,000)
Prior period adjustment to operating earnings tax expense		(2,000,000)
Corporate & Other [Member]
Segment Reporting Information [Line Items]
Prior period operating earnings reclassifications to conform with current period presentation		27,000,000
Prior period adjustment to operating earnings tax expense		$ 16,000,000