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	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Financial Assets
Cash and due from banks	$ 16,932	$ 21,453	$ 19,021	$ 19,505
Investment securities held-to-maturity	46,383	46,050
Loans	288,009	282,837
Financial Liabilities
Long-term debt	41,008	41,340
Carrying Amount [Member]
Financial Assets
Cash and due from banks	16,932	21,453
Federal funds sold and securities purchased under resale agreements	4,128	306
Investment securities held-to-maturity	46,383	46,050
Loans held for sale	56	21
Loans	288,009	282,837
Other	1,851	2,412
Financial Liabilities
Time deposits	45,106	44,554
Short-term borrowings	13,567	12,921
Long-term debt	41,008	41,340
Other	2,161	1,726
Fair Value [Member]
Financial Assets
Cash and due from banks	16,932	21,453
Federal funds sold and securities purchased under resale agreements	4,128	306
Investment securities held-to-maturity	46,350	44,964
Loans held for sale	56	21
Loans	292,516	284,790
Other	1,851	2,412
Financial Liabilities
Time deposits	45,075	44,140
Short-term borrowings	13,376	12,678
Long-term debt	41,712	41,003
Other	3,542	1,726
Fair Value [Member] \| Level 1 [Member]
Financial Assets
Cash and due from banks	16,932	21,453
Investment securities held-to-maturity	4,305	4,594
Fair Value [Member] \| Level 2 [Member]
Financial Assets
Federal funds sold and securities purchased under resale agreements	4,128	306
Investment securities held-to-maturity	42,036	40,359
Other	900	1,241
Financial Liabilities
Time deposits	45,075	44,140
Short-term borrowings	13,376	12,678
Long-term debt	41,712	41,003
Other	1,381
Fair Value [Member] \| Level 3 [Member]
Financial Assets
Investment securities held-to-maturity	9	11
Loans held for sale	56	21
Loans	292,516	284,790
Other	951	1,171
Financial Liabilities
Other	$ 2,161	$ 1,726