Financial Services Finance Receivables - Credit Quality (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	$ 101,961	$ 96,674	$ 95,736
Consumer [Member]
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	$ 68,153	65,338	62,185
Consumer [Member] | Minimum [Member] | Special Mention [Member]
Credit quality [Line Items]
Finance Receivables Credit Quality Ratings Term Range	61 days
Consumer [Member] | Minimum [Member] | Substandard [Member]
Credit quality [Line Items]
Finance Receivables Credit Quality Ratings Term Range	120 days
Consumer [Member] | Maximum [Member] | Pass [Member]
Credit quality [Line Items]
Finance Receivables Credit Quality Ratings Term Range	60 days
Consumer [Member] | Maximum [Member] | Special Mention [Member]
Credit quality [Line Items]
Finance Receivables Credit Quality Ratings Term Range	120 days
Non-consumer [Member]
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	$ 33,808	31,336	$ 33,551
Non-consumer [Member] | Dealer financing [Member]
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	33,808	31,336
Non-consumer [Member] | Dealer financing [Member] | Group I
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	26,688	24,315
Non-consumer [Member] | Dealer financing [Member] | Group II
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	5,589	5,552
Non-consumer [Member] | Dealer financing [Member] | Group III
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	1,364	1,376
Non-consumer [Member] | Dealer financing [Member] | Group IV
Credit quality [Line Items]
Financing Receivable By Credit Quality Indicator	$ 167	$ 93