Shareowners' Equity (Summary Noncontrolling Interests) (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2015		Dec. 31, 2014		Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	[1]
Summary To Noncontrolling Interest [Line Items]
Synchrony Financial	$ 2,790		$ 2,531
Other noncontrolling interests	370		368
Noncontrolling interests	$ 3,160	[1],[2]	$ 2,899	[1],[2]	$ 3,083	$ 2,804	$ 350	$ 432

[1] (c) Included AOCI attributable to noncontrolling interests of $ (178) million and $ (154) million at September 30, 2015 and December 31, 2014 , respectively.

[2] Amounts may not add due to rounding.