Regulatory Capital and Other Regulatory Matters (Depository Institutions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total assets	$ 191,826	$ 182,114	$ 182,165
Dividends from bank subsidiary	3,200	3,500
Statutory accounting practices, statutory amount available for dividend payments	101
Ally Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total assets	$ 181,900	$ 172,800