Recent Accounting Pronouncements (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 19,240	$ 18,778	$ 16,945
Net cash provided by (used in) financing activities	151	(8,429)	(6,020)
Share Based Compensation New Accounting Pronouncement [Member] \| As Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	19,240	18,778	16,945
Net cash provided by (used in) financing activities	151	(8,429)	(6,020)
Share Based Compensation New Accounting Pronouncement [Member] \| Effect of Adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in income tax expense	$ 233
Decrease in effective income tax rate	1.60%
Increase in diluted earnings per share (in dollars per share)	$ 0.08
Net cash provided by operating activities	$ 585	708	652
Net cash provided by (used in) financing activities	(585)	(708)	(652)
Share Based Compensation New Accounting Pronouncement [Member] \| Upon Adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	19,825	19,486	17,597
Net cash provided by (used in) financing activities	$ (434)	$ (9,137)	$ (6,672)

Impact on income tax expense if new accounting pronouncement was adopted.

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- Definition

Impact on effective tax rate if new accounting pronouncement was adopted.

+ References

No definition available.

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- Definition

Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

+ References

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- Definition

Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3521-108585

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Amount of the effect of a change in accounting principle on diluted earnings per share.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Retrospective Application
-URI http://asc.fasb.org/extlink&oid=6523989

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Direct Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=66092750

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accounting Change
-URI http://asc.fasb.org/extlink&oid=6503790

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22580-107794

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6507316

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
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-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794

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-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Indirect Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6515603

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-Name Accounting Standards Codification
-Topic 260
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-URI http://asc.fasb.org/extlink&oid=64863997&loc=d3e1278-109256

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