Accounting Policies - Accounting Pronouncements (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets	$ 30,939	$ 29,158
Total assets	94,156	92,437
Deferred tax liabilities - noncurrent	4,254	4,217
Total liabilities and shareholders’ equity	$ 94,156	92,437
Adjustments for New Accounting Principle, Early Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets - current		0
Total current assets		29,158
Total assets		92,437
Deferred tax liabilities - noncurrent		4,217
Total liabilities and shareholders’ equity		92,437
Adjustments for New Accounting Principle, Early Adoption | Scenario, Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets - current		1,220
Total current assets		30,378
Total assets		93,657
Deferred tax liabilities - noncurrent		5,437
Total liabilities and shareholders’ equity		93,657
Adjustments for New Accounting Principle, Early Adoption | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets - current		(1,220)
Total current assets		(1,220)
Total assets		(1,220)
Deferred tax liabilities - noncurrent		(1,220)
Total liabilities and shareholders’ equity		$ (1,220)