Fair Values of Assets and Liabilities - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Financial Assets
Cash and due from banks	$ 76,985	$ 61,192
Investment securities held-to-maturity	71,149	74,088
Financial Liabilities
Long-term debt	52,693	51,480
Carrying Amount
Financial Assets
Cash and due from banks	76,985	61,192
Federal funds sold and securities purchased under resale agreements	3,788	2,543
Investment securities held-to-maturity	82,948	84,045
Loans held for sale	195	190
Loans	367,074	366,456
Other	2,140	2,377
Financial Liabilities
Time deposits	51,395	49,455
Short-term borrowings	14,843	12,976
Long-term debt	52,693	51,480
Other	5,176	5,432
Fair Value
Financial Assets
Cash and due from banks	76,985	61,192
Federal funds sold and securities purchased under resale agreements	3,788	2,543
Investment securities held-to-maturity	71,149	74,088
Loans held for sale	195	190
Loans	358,357	362,849
Other	2,140	2,377
Financial Liabilities
Time deposits	51,568	49,607
Short-term borrowings	14,549	12,729
Long-term debt	50,805	49,697
Other	5,176	5,432
Fair Value \| Level 1
Financial Assets
Cash and due from banks	76,985	61,192
Federal funds sold and securities purchased under resale agreements	0	0
Investment securities held-to-maturity	1,303	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	3,788	2,543
Investment securities held-to-maturity	69,846	72,778
Loans held for sale	0	0
Loans	0	0
Other	1,588	1,863
Financial Liabilities
Time deposits	51,568	49,607
Short-term borrowings	14,549	12,729
Long-term debt	50,805	49,697
Other	1,341	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	195	190
Loans	358,357	362,849
Other	552	514
Financial Liabilities
Time deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Other	$ 3,835	$ 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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