Marketable and Other Securities - Fair Value of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	$ 21,299
Total cash and cash equivalents	38,506	$ 19,069
Cash and cash equivalents	239	292
Total restricted cash	2,660	3,874
Due in one year or less	18,605
Due between one and five years	2,694
Total available-for-sale debt securities with contractual maturities	21,299
Cruise [Member]
Marketable Securities [Line Items]
Total cash and cash equivalents	1,500	2,300
GM Korea [Member]
Marketable Securities [Line Items]
Cash and time deposits		248
Cash and cash equivalents [Member]
Marketable Securities [Line Items]
Cash and time deposits	11,965	6,828
Total available-for-sale debt securities with contractual maturities	14,346	9,470
Total available-for-sale debt securities with contractual maturities	14,346	9,470
Cash and cash equivalents [Member] \| Level 1 [Member]
Marketable Securities [Line Items]
Money market funds	12,195	2,771
Marketable debt securities [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	7,620	4,174
Total available-for-sale debt securities with contractual maturities	7,620	4,174
Marketable debt securities [Member] \| Cruise [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	877	266
Total available-for-sale debt securities with contractual maturities	877	266
Other current assets [Member] \| Level 1 [Member]
Marketable Securities [Line Items]
Money market funds	2,421	3,582
U.S. government and agencies [Member] \| Cash and cash equivalents [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	5,011	1,484
Total available-for-sale debt securities with contractual maturities	5,011	1,484
U.S. government and agencies [Member] \| Marketable debt securities [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	1,810	226
Total available-for-sale debt securities with contractual maturities	1,810	226
Corporate debt [Member] \| Cash and cash equivalents [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	7,660	5,863
Total available-for-sale debt securities with contractual maturities	7,660	5,863
Corporate debt [Member] \| Marketable debt securities [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	3,104	2,932
Total available-for-sale debt securities with contractual maturities	3,104	2,932
Mortgage and asset-backed [Member] \| Marketable debt securities [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	667	681
Total available-for-sale debt securities with contractual maturities	667	681
Sovereign debt [Member] \| Cash and cash equivalents [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	1,675	2,123
Total available-for-sale debt securities with contractual maturities	1,675	2,123
Sovereign debt [Member] \| Marketable debt securities [Member] \| Level 2 [Member]
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	2,039	335
Total available-for-sale debt securities with contractual maturities	$ 2,039	$ 335

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