Marketable and Other Securities - Fair Value of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Marketable Securities [Line Items]
Total cash and cash equivalents	$ 19,069	$ 20,844
Cash and cash equivalents	292	260
Total restricted cash	3,874	2,652
Due in one year or less	10,213
Due between one and five years	2,750
Total available-for-sale debt securities with contractual maturities	12,963
GM Korea
Marketable Securities [Line Items]
Cash and time deposits	248	616
Cruise
Marketable Securities [Line Items]
Total cash and cash equivalents	2,300	2,300
Cash And Cash Equivalents
Marketable Securities [Line Items]
Cash and time deposits	6,828	7,254
Total available-for-sale debt securities with contractual maturities	9,470	10,423
Cash And Cash Equivalents \| Level 2 \| U.S. government and agencies
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	1,484	4,656
Cash And Cash Equivalents \| Level 2 \| Corporate Debt
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	5,863	3,791
Cash And Cash Equivalents \| Level 2 \| Sovereign Debt
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	2,123	1,976
Cash And Cash Equivalents \| Level 1
Marketable Securities [Line Items]
Money market funds	2,771	3,167
Marketable Securities
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	4,174	5,966
Marketable Securities \| Cruise
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	266
Marketable Securities \| Level 2 \| U.S. government and agencies
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	226	1,230
Marketable Securities \| Level 2 \| Corporate Debt
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	2,932	3,478
Marketable Securities \| Level 2 \| Sovereign Debt
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	335	563
Marketable Securities \| Level 2 \| Mortgage and asset-backed
Marketable Securities [Line Items]
Total available-for-sale debt securities with contractual maturities	681	695
Restricted cash - cash equivalents \| Level 1
Marketable Securities [Line Items]
Money market funds	$ 3,582	$ 2,392

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