Recent Accounting Pronouncements (Details) - USD ($) shares in Thousands, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense (benefit)		$ 290	$ 334	$ 905	$ 1,009
Common stock equivalents		4,235	4,449	4,326	4,451
Other, net (operating)	[1]			$ 25	$ (4)
Net cash provided by operating activities	[1]			3,074	1,797
Other, net (financing)	[1]			(87)	(83)
Net cash provided by financing activities	[1]			(255)	(503)
Accounting Standards Update 2016-09 [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax expense (benefit)				$ (25)
Common stock equivalents				1,000
Other, net (operating)				$ 69	78
Net cash provided by operating activities				69	78
Other, net (financing)				(69)	(78)
Net cash provided by financing activities				$ (69)	$ (78)

[1] As required by the adoption of ASU 2016-09, the Company retrospectively reclassified $78 million of cash payments from operating to financing activities for the nine months ended September 30, 2015. These payments were related to employee tax obligations associated with stock compensation. The comparable amount reported in financing activities for the nine months ended September 30, 2016 was $69 million. See Note 2 for further discussion.