Revenue Revenue - Remaining Performance Obligation (Details) - Operating Segments [Member] - Automotive - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Jan. 01, 2017
Vehicles, parts, and accessories
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue Performance Obligation Satisfied In Prior Period	$ 33
Extended service contracts
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Contract With Customer Liability			$ 3,500
Contract With Customer Liability Revenue Recognized	256	$ 797
Revenue Remaining Performance Obligation	3,700	3,700
Deferrred cost	236	236
Amortization	17	$ 46
Minimum [Member] | Vehicles, parts, and accessories
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue Performance Obligation Payment Terms		30 days
Minimum [Member] | Extended service contracts
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		12 months
Minimum [Member] | Other revenue (a)
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		1 year
Maximum [Member] | Vehicles, parts, and accessories
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue Performance Obligation Payment Terms		120 days
Maximum [Member] | Extended service contracts
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		120 months
Maximum [Member] | Other revenue (a)
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		2 years
2017-01-01 [Member] | Extended service contracts
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		1 year
Revenue Remaining Performance Obligation	300	$ 300
2018-01-01 [Member] | Extended service contracts
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		1 year
Revenue Remaining Performance Obligation	1,000	$ 1,000
2019-01-01 [Member] | Extended service contracts
Revenue Remaining Performance Obligation Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation expected timing of satisfaction period		8 years
Revenue Remaining Performance Obligation	$ 2,400	$ 2,400