Marketable and Other Securities - Fair Value of Cash Equivalents and Marketable Debt Securities (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	$ 9,403
Total cash and cash equivalents	22,381	$ 19,872
Cash and cash equivalents	370	294
Total restricted cash	3,418	3,092
Due in one year or less	4,216
Due between one and five years	5,188
Total available-for-sale debt securities with contractual maturities	9,403
Cash and cash equivalents
Summary of Investment Holdings [Line Items]
Cash and time deposits	12,547	12,471
Total available-for-sale debt securities with contractual maturities	3,068	2,351
Total available-for-sale debt securities with contractual maturities	3,068	2,351
Cash and cash equivalents \| Level 2 \| U.S. government and agencies
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	498	26
Total available-for-sale debt securities with contractual maturities	498	26
Cash and cash equivalents \| Level 2 \| Corporate debt
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	2,193	1,541
Total available-for-sale debt securities with contractual maturities	2,193	1,541
Cash and cash equivalents \| Level 2 \| Sovereign debt
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	378	785
Total available-for-sale debt securities with contractual maturities	378	785
Cash and cash equivalents \| Level 1
Summary of Investment Holdings [Line Items]
Money market funds	6,766	5,050
Marketable debt securities
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	6,958	7,265
Total available-for-sale debt securities with contractual maturities	6,958	7,265
Marketable debt securities \| Level 2 \| U.S. government and agencies
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	2,610	3,082
Total available-for-sale debt securities with contractual maturities	2,610	3,082
Marketable debt securities \| Level 2 \| Mortgage and asset-backed
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	509	591
Total available-for-sale debt securities with contractual maturities	509	591
Marketable debt securities \| Level 2 \| Corporate debt and other
Summary of Investment Holdings [Line Items]
Total available-for-sale debt securities with contractual maturities	3,840	3,592
Total available-for-sale debt securities with contractual maturities	3,840	3,592
Other Current Assets \| Level 1
Summary of Investment Holdings [Line Items]
Money market funds	$ 3,048	$ 2,798

General Motors Co 10-Q