Revisions - Income Statement (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes	$ 912	$ 1,089	$ 933	$ 3,026	$ 2,820
Net income from continuing operations	3,979	3,515	2,924	11,425	9,912
Net income	$ 3,979	$ 3,515	$ 2,739	$ 11,425	$ 9,461
Continuing operations - basic (in dollars per share)		$ 5.16	$ 4.32		$ 14.69
Net income per share - basic (in dollars per share)		5.16	4.05		14.02
Continuing operations - diluted (in dollars per share)		5.10	4.25		14.44
Net income per share - diluted (in dollars per share)		$ 5.10	$ 3.98		$ 13.78
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes		$ 1,018	$ 859		$ 2,594
Net income from continuing operations		3,586	2,998		10,138
Net income		$ 3,586	$ 2,813		$ 9,687
Continuing operations - basic (in dollars per share)		$ 5.27	$ 4.42		$ 15.02
Net income per share - basic (in dollars per share)		5.27	4.15		14.35
Continuing operations - diluted (in dollars per share)		5.20	4.36		14.77
Net income per share - diluted (in dollars per share)		$ 5.20	$ 4.09		$ 14.11
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes		$ 71	$ 74		$ 226
Net income from continuing operations		(71)	(74)		(226)
Net income		$ (71)	$ (74)		$ (226)
Continuing operations - basic (in dollars per share)		$ (0.11)	$ (0.10)		$ (0.33)
Net income per share - basic (in dollars per share)		(0.11)	(0.10)		(0.33)
Continuing operations - diluted (in dollars per share)		(0.10)	(0.11)		(0.33)
Net income per share - diluted (in dollars per share)		$ (0.10)	$ (0.11)		$ (0.33)