Segments (Revenue by segments) (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenue
Revenue	$ 19,590	$ 22,236	[1]
Total Segments
Revenue
Revenue	19,523	22,128	[1],[2]
Total reportable segments | Total Segments
Revenue
Revenue	21,491	24,228	[1],[2]
Eliminations of internal transactions
Revenue
Revenue	(1,968)	(2,099)	[1],[2]
Other revenue adjustments
Revenue
Revenue	$ 67	$ 107	[1]

[1] Reclassified to reflect discontinued operation presentation.

[2] Reclassified to conform with 2015 presentation and to reflect discontinued operations presentation.