Accounting Changes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2016	Dec. 31, 2014
Accounting Changes
Operating lease commitments	$ 6,400
Sales-type lease revenue recognized based on use of residual value guarantee insurance	608
Deferred tax assets	4,822	$ 4,289
Other accrued expenses and liabilities	4,353	5,346
Other liabilities	8,099	8,138
Debt issuance costs	74	86
Accounting Standards Update 2015-17, Balance Sheet Classification of Deferred Taxes | Standards Implemented | Reclassification from current to noncurrent
Accounting Changes
Current deferred tax assets			$ (2,000)
Deferred tax assets			2,000
Other accrued expenses and liabilities			(19)
Other liabilities			19
Accounting Standards Update 2015-17, Balance Sheet Classification of Deferred Taxes | Standards Implemented | Reclassification from assets to liabilities
Accounting Changes
Deferred tax assets			(178)
Other liabilities			$ (178)
Accounting Standards Update 2015-03, Interest-Imputation of Interest
Accounting Changes
Debt issuance costs	$ 74	$ 86