Debt (Pledged Assets Related to Secured Borrowings and Repurchase Agreement) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	$ 42,658	$ 39,265
Secured debt	11,286	10,124
Amortized cost	34,272	34,863
Short-term borrowings	1,455	2,399
Asset Pledged as Collateral
Pledged Assets related to secured borrowings [Line Items]
Amortized cost	5,008	4,288
Pledged assets for Federal Home Loan Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	28,400	27,000
Pledged assets for Federal Reserve Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	2,300	2,400
Investment securities
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	4,241	3,525
Consumer \| Consumer mortgage
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	19,499	19,771
Consumer \| Automotive
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	13,505	11,759
Commercial
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	$ 5,413	$ 4,210

Amount of assets pledged to secure a debt instrument.

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Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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