Fair Values of Assets and Liabilities - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Financial Assets
Cash and due from banks	$ 73,562	$ 61,192
Investment securities held-to-maturity	71,415	74,088
Financial Liabilities
Long-term debt	54,839	51,480
Carrying Amount
Financial Assets
Cash and due from banks	73,562	61,192
Federal funds sold and securities purchased under resale agreements	6,426	2,543
Investment securities held-to-maturity	80,025	84,045
Loans held for sale	324	190
Loans	366,604	366,456
Other	2,436	2,377
Financial Liabilities
Time deposits	51,686	49,455
Short-term borrowings	21,302	12,976
Long-term debt	54,794	51,480
Other	4,800	5,432
Fair Value
Financial Assets
Cash and due from banks	73,562	61,192
Federal funds sold and securities purchased under resale agreements	6,426	2,543
Investment securities held-to-maturity	71,415	74,088
Loans held for sale	324	190
Loans	363,988	362,849
Other	2,436	2,377
Financial Liabilities
Time deposits	51,918	49,607
Short-term borrowings	21,174	12,729
Long-term debt	54,468	49,697
Other	4,800	5,432
Fair Value \| Level 1
Financial Assets
Cash and due from banks	73,562	61,192
Federal funds sold and securities purchased under resale agreements	0	0
Investment securities held-to-maturity	1,280	1,310
Loans held for sale	0	0
Loans	0	0
Other	0	0
Financial Liabilities
Time deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Other	0	0
Fair Value \| Level 2
Financial Assets
Cash and due from banks	0	0
Federal funds sold and securities purchased under resale agreements	6,426	2,543
Investment securities held-to-maturity	70,135	72,778
Loans held for sale	0	0
Loans	0	0
Other	1,910	1,863
Financial Liabilities
Time deposits	51,918	49,607
Short-term borrowings	21,174	12,729
Long-term debt	54,468	49,697
Other	1,327	1,406
Fair Value \| Level 3
Financial Assets
Cash and due from banks	0	0
Federal funds sold and securities purchased under resale agreements	0	0
Investment securities held-to-maturity	0	0
Loans held for sale	324	190
Loans	363,988	362,849
Other	526	514
Financial Liabilities
Time deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Other	$ 3,473	$ 4,026

For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Includes: (1) the amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements (Federal Funds Sold) and (2) the dollar amount outstanding of funds lent in the form of security resale agreements regardless of maturity, if the agreement requires the bank to resell the identical security purchased or a security that meets the definition of substantially the same in the case of a dollar roll. Also include purchases of participations in pools of securities, regardless of maturity (Securities Purchased Under Agreements to Re-sell).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount of long-term debt and lease obligation, including portion classified as current.

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Amount of time deposit liabilities, including certificates of deposit.

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Other financial assets.

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