Nature of Operations and Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2021
Nature of Operations and Basis of Presentation [Abstract]
Basis of Accounting	The condensed consolidated financial statements have been prepared in conformity with U.S. GAAP pursuant to the rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. The condensed consolidated financial statements include all adjustments, which consist of normal recurring adjustments and transactions or events discretely impacting the interim periods, considered necessary by management to fairly state our results of operations, financial position and cash flows. The operating results for interim periods are not necessarily indicative of results that may be expected for any other interim period or for the full year. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our 2020 Form 10-K. Except for per share amounts or as otherwise specified, amounts presented within tables are stated in millions.
Principles of Consolidation	Principles of Consolidation We consolidate entities that we control due to ownership of a majority voting interest and we consolidate variable interest entities (VIEs) when we are the primary beneficiary. All intercompany balances and transactions have been eliminated in consolidation. Our share of earnings or losses of nonconsolidated affiliates is included in our consolidated operating results using the equity method of accounting when we are able to exercise significant influence over the operating and financial decisions of the affiliate.
GM Financial	GM Financial The amounts presented for GM Financial have been adjusted to reflect the impact on GM Financial's deferred tax positions and provision for income taxes resulting from the inclusion of GM Financial in our consolidated tax return and to eliminate the effect of transactions between GM Financial and the other members of the consolidated group. Accordingly, the amounts presented will differ from those presented by GM Financial on a stand-alone basis.

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109239629&loc=d3e5614-111684

Name:	us-gaap_ConsolidationPolicyTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration