Commitments and Contingencies Loss Contingencies (Details) CAD in Millions, $ in Millions, ₩ in Billions	1 Months Ended		6 Months Ended
	Oct. 31, 2012	Feb. 28, 2010	Jun. 30, 2015 USD ($) employee	Jun. 30, 2015 CAD employee	Jul. 20, 2015	Jun. 30, 2015 KRW (₩)
BRAZIL
Loss Contingencies [Line Items]
Increase in Excise Tax Rate	30.00%
Minimum [Member]
Loss Contingencies [Line Items]
Indirect Tax-Related Escrow Deposit			$ 400
Maximum [Member]
Loss Contingencies [Line Items]
Indirect Tax-Related Escrow Deposit			$ 600
Ignition Switch Recall Litigations [Member]
Loss Contingencies [Line Items]
State Attorneys General, Number			50	50
GMCL Dealer Litigation [Member]
Loss Contingencies [Line Items]
Number of Plaintiffs		200	181	181
Damages Sought, Value | CAD				CAD 750
UAW Lawsuit [Member]
Loss Contingencies [Line Items]
Damages Sought, Value			$ 450
Korea Wage Litigation - Hourly [Member]
Loss Contingencies [Line Items]
Number of Plaintiffs | employee			10,000	10,000
Number Of Group Actions			8	8
Number of Employees in the Case | employee			5	5
Range of Possible Loss, Portion Not Accrued			$ 515			₩ 574
Korea Wage Litigation - Salaried [Member]
Loss Contingencies [Line Items]
Range of Possible Loss, Portion Not Accrued			$ 155			₩ 173
Subsequent Event [Member] | Ignition Switch Recall Litigations - Economic Damage [Member] | U.S.
Loss Contingencies [Line Items]
Number of Pending Claims					100
Subsequent Event [Member] | Ignition Switch Recall Litigations - Economic Damage [Member] | CANADA
Loss Contingencies [Line Items]
Number of Pending Claims					21
Subsequent Event [Member] | Ignition Switch Recall Litigations - Injury or Death [Member] | U.S.
Loss Contingencies [Line Items]
Number of Pending Claims					172
Subsequent Event [Member] | Ignition Switch Recall Litigations - Injury or Death [Member] | CANADA
Loss Contingencies [Line Items]
Number of Pending Claims					9
Consolidated Litigation [Member] | Ignition Switch Recall Litigations - Shareholder Derivative Action [Member] | Eastern District of Michigan [Member]
Loss Contingencies [Line Items]
Number of Pending Claims			2			2
Consolidated Litigation [Member] | Ignition Switch Recall Litigations - Shareholder Derivative Action [Member] | DELAWARE
Loss Contingencies [Line Items]
Number of Pending Claims			4			4
Consolidated Litigation [Member] | Ignition Switch Recall Litigations - Shareholder Derivative Action [Member] | Wayne County, Michigan
Loss Contingencies [Line Items]
Number of Pending Claims			2			2
Consolidated Litigation [Member] | Subsequent Event [Member] | Ignition Switch Recall Litigations [Member] | NEW YORK
Loss Contingencies [Line Items]
Number of Claims Transferred					204