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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Fair Values of Assets and Liabilities - Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Financial Assets
Cash and due from banks	$ 15,272	$ 21,453	$ 20,082	$ 19,505
Investment securities held-to-maturity	46,481	46,050
Loans	290,631	282,837
Financial Liabilities
Long-term debt	41,274	41,340
Carrying Amount [Member]
Financial Assets
Cash and due from banks	15,272	21,453
Federal funds sold and securities purchased under resale agreements	3,907	306
Investment securities held-to-maturity	46,481	46,050
Loans held for sale	676	21
Loans	290,631	282,837
Other	1,873	2,412
Financial Liabilities
Time deposits	40,219	44,554
Short-term borrowings	12,975	12,921
Long-term debt	41,274	41,340
Other	3,636	1,726
Fair Value [Member]
Financial Assets
Cash and due from banks	15,272	21,453
Federal funds sold and securities purchased under resale agreements	3,907	306
Investment securities held-to-maturity	46,638	44,964
Loans held for sale	676	21
Loans	294,850	284,790
Other	1,873	2,412
Financial Liabilities
Time deposits	40,147	44,140
Short-term borrowings	12,813	12,678
Long-term debt	41,902	41,003
Other	3,636	1,726
Fair Value [Member] \| Level 1 [Member]
Financial Assets
Cash and due from banks	15,272	21,453
Investment securities held-to-maturity	4,106	4,594
Fair Value [Member] \| Level 2 [Member]
Financial Assets
Federal funds sold and securities purchased under resale agreements	3,907	306
Investment securities held-to-maturity	42,523	40,359
Other	941	1,241
Financial Liabilities
Time deposits	40,147	44,140
Short-term borrowings	12,813	12,678
Long-term debt	41,902	41,003
Other	1,344
Fair Value [Member] \| Level 3 [Member]
Financial Assets
Investment securities held-to-maturity	9	11
Loans held for sale	676	21
Loans	294,850	284,790
Other	932	1,171
Financial Liabilities
Other	$ 2,292	$ 1,726