Summary Of Significant Accounting Policies Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]
Business Combinations Policy [Policy Text Block]	Acquisition of Ally Financial International Operations We acquired Ally Financial Inc.'s ("Ally Financial") auto finance and financial services operations in Germany, the United Kingdom (the "U.K."), Italy, Sweden, Switzerland, Austria, Belgium, the Netherlands, Greece, Spain, Chile, Colombia and Mexico on April 1, 2013. We acquired Ally Financial's auto finance and financial services operations in France and Portugal on June 1, 2013, and we acquired Ally Financial's auto finance and financial services operations in Brazil on October 1, 2013. Additionally, we have agreed to acquire Ally Financial's non-controlling 40% equity interest in GMAC-SAIC Automotive Finance Company Limited ("GMAC-SAIC"), a joint venture, which conducts auto finance operations in China. This agreement is subject to certain regulatory and other approvals. We consider it probable that our acquisition of Ally Financial's interest in GMAC-SAIC will occur in late 2014 or as soon as practicable thereafter. The results of operations of the acquired entities since the applicable acquisition dates are included in our financial statements for the three and nine months ended September 30, 2014 and 2013.
Segment Reporting, Policy [Policy Text Block]	Segment Information We evaluate our business in two operating segments: North America ("the North America Segment") and international ("the International Segment"). The North America Segment includes our operations in the U.S. and Canada. The International Segment includes our operations in all other countries. For additional financial information regarding our business segments, see Note 12 - "Segment Reporting."
Business Presentation, Policy	Basis of Presentation The condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including certain special-purpose financing entities utilized in secured financing transactions, which are considered variable interest entities ("VIEs"). All intercompany transactions and balances have been eliminated in consolidation. The interim period consolidated financial statements, including the notes thereto, are condensed and do not include all disclosures required by generally accepted accounting principles ("GAAP") in the United States of America. These interim period condensed consolidated financial statements should be read in conjunction with the consolidated financial statements that are included in our Annual Report on Form 10-K filed on February 6, 2014 ("Form 10-K"). Certain prior periods amounts were reclassified to conform to our current year presentation. The condensed consolidated financial statements at September 30, 2014, and for the three and nine months ended September 30, 2014 and 2013, are unaudited and, in management’s opinion, include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the results for such interim periods. The results for interim periods are not necessarily indicative of results for a full year. The preparation of financial statements in conformity with GAAP in the United States of America requires management to make estimates and assumptions which affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements and the amount of revenue and costs and expenses during the reporting periods. Actual results could differ from those estimates and those differences may be material. These estimates include, among other things, the determination of the allowance for loan losses on finance receivables, estimated recovery value on leased vehicles, goodwill, income taxes and the expected cash flows on the pre-acquisition consumer finance receivables.
Related Party Transaction [Policy Text Block]	Related Party Transactions We are the wholly-owned captive finance subsidiary of our parent, General Motors Company ("GM"). We offer loan and lease finance products through GM-franchised dealers to consumers purchasing new and certain used vehicles manufactured by GM and make commercial loans directly to GM-franchised dealers. Under subvention programs, GM makes cash payments to us for offering incentivized rates and structures on consumer loan and lease finance products. In addition, GM makes payments to us to cover certain interest payments on commercial loans. At September 30, 2014 and December 31, 2013, we had related party receivables from GM in the amount of $195 million and $129 million under these programs. At September 30, 2014 and December 31, 2013 we had $116 million and $62 million in loans outstanding to dealers that are consolidated by GM, in connection with our commercial lending program. Our international operations also provide financing to certain GM subsidiaries through factoring and other wholesale financing arrangements. At September 30, 2014 and December 31, 2013, $342 million and $588 million were outstanding under such arrangements, and are included in commercial finance receivables. At September 30, 2014 and December 31, 2013, we had $603 million and $368 million of related party payables due to GM, primarily for commercial finance receivables originated but not yet funded. These payables typically settle within 30 days. We have a tax sharing agreement with GM for our U.S. operations, and we are obligated to pay GM for our share of the consolidated U.S. federal and certain state tax liabilities for taxable income recognized by us in any period beginning on or after October 1, 2010. Payments for the tax years 2010 through 2014 are deferred for four years from their original due date, and the total deferral amount is to not exceed $1.0 billion. The tax sharing agreement may be modified at any time by GM in its sole discretion. At September 30, 2014 and December 31, 2013, we had related party taxes payable to GM in the amount of $877 million and $643 million. In September 2014, we and GM entered into a Support Agreement (the “Support Agreement”). Pursuant to the Support Agreement, if our earning assets leverage at the end of any calendar quarter is higher than thresholds set in the Support Agreement, We may require GM to provide funding sufficient to bring our earning assets leverage to within the appropriate threshold. In determining our earning assets leverage (net earning assets divided by adjusted equity) under the Support Agreement, net earning assets means our finance receivables, net, plus leased vehicles, net, and adjusted equity means our equity, net of goodwill and inclusive of outstanding junior subordinated debt. At September 30, 2014, our earning assets leverage ratio was 7.0, which is below the current applicable ratio of 8.0. Additionally, the Support Agreement provides that GM will own all of our outstanding voting shares as long as we have any unsecured debt securities outstanding and that GM will use its commercially reasonable efforts to ensure that we will continue to be designated as a subsidiary borrower on $4.0 billion under GM’s corporate revolving credit facilities. GM also agreed to certain provisions intended to ensure that we maintain adequate access to liquidity. Pursuant to these provisions, GM provided us with a $1.0 billion unsecured intercompany revolving credit facility (the “Junior Subordinated Revolving Credit Facility”), which replaced an existing $600 million intercompany credit facility with GM. There were no advances outstanding under the Junior Subordinated Revolving Credit Facility at September 30, 2014. In October 2014, GM amended its two primary unsecured revolving credit facilities increasing GM's aggregate borrowing capacity from $11.0 billion to $12.5 billion. These facilities consist of a three-year, $5.0 billion facility and a five-year, $7.5 billion facility. We have the ability to borrow up to $2.0 billion against each of GM's unsecured revolving credit facilities, subject to available capacity. Our borrowings under GM's facilities are limited by GM's ability to borrow the entire amount available under the facilities. Therefore, we may be able to borrow up to $4.0 billion in total or may be unable to borrow depending on GM's borrowing activity. If we do borrow under these facilities, we expect such borrowings would be short-term in nature and, except in extraordinary circumstances, would not be used to fund our operating activities in the ordinary course of business. Neither we, nor any of our subsidiaries, guarantee any obligations under these facilities and none of our or our subsidiaries' assets secure these facilities.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Principles On January 1, 2014 we adopted Accounting Standards Update ("ASU") 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” which was issued to eliminate diversity in practice. This ASU requires that companies net their unrecognized tax benefits against all same-jurisdiction net operating losses or tax credit carryforwards that would be used to settle the position with a tax authority. The adoption of this ASU did not have a material effect on our consolidated financial statements. Accounting Standards Not Yet Adopted In May 2014 the Financial Accounting Standards Board issued ASU 2014-09, “Revenue Recognition - Revenue from Contracts with Customers” ("ASU 2014-09") that requires companies to recognize revenue when a customer obtains control rather than when companies have transferred substantially all risks and rewards of a good or service. This update is effective for annual reporting periods beginning on or after December 15, 2016 and interim periods therein and requires expanded disclosures. We are currently assessing the impact the adoption of ASU 2014-09 will have on our condensed consolidated financial statements.

Disclosure of accounting policy for completed business combinations (purchase method, acquisition method or combination of entities under common control). This accounting policy may include a general discussion of the purchase method or acquisition method of accounting (including for example, the treatment accorded contingent consideration, the identification of assets and liabilities, the purchase price allocation process, how the fair values of acquired assets and liabilities are determined) and the entity's specific application thereof. An entity that acquires another entity in a leveraged buyout transaction generally discloses the accounting policy followed by the acquiring entity in determining the basis used to value its interest in the acquired entity, and the rationale for that accounting policy.

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